22 changed files with 258 additions and 3784 deletions
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -2,9 +2,6 @@ version: 2
 updates:
  - package-ecosystem: cargo
    directory: '/'
-    # Update only the lockfile. We shouldn't update Cargo.toml unless it's for
-    # a security issue, or if we need a new feature of the dependency.
-    versioning-strategy: lockfile-only
    schedule:
      interval: daily
      timezone: America/New_York
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -10,72 +10,70 @@ jobs:
  check:
    name: Check
    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - stable
    steps:
      - uses: actions/checkout@v4
        with:
          submodules: true
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
      - uses: actions-rs/cargo@v1
        with:
          command: check

-  # Test that "cargo package" works. This makes sure it's publishable,
+  # Test that "cargo package" works. This make sure it's publishable,
  # since we had issues where "cargo build" worked but "package" didn't.
  package:
    name: Package
    runs-on: ubuntu-latest
    strategy:
-      fail-fast: false
      matrix:
-        toolchain:
-          - rust-toolchain.toml
+        rust:
+          - stable
          - nightly
    steps:
      - uses: actions/checkout@v4
        with:
          submodules: true
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
      - uses: actions-rs/cargo@v1
-        if: matrix.toolchain == 'rust-toolchain.toml'
        with:
          command: package
-      - run: rustup install ${{ matrix.toolchain }}
-        if: matrix.toolchain != 'rust-toolchain.toml'
-      - uses: actions-rs/cargo@v1
-        if: matrix.toolchain != 'rust-toolchain.toml'
-        with:
-          command: package
-          toolchain: ${{ matrix.toolchain }}

  test-versions:
    name: Test Suite
    runs-on: ubuntu-latest
    strategy:
-      fail-fast: false
      matrix:
-        toolchain:
-          - rust-toolchain.toml
+        rust:
+          - stable
          - nightly
    steps:
      - uses: actions/checkout@v4
        with:
          submodules: true
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
      - uses: actions-rs/cargo@v1
-        if: matrix.toolchain == 'rust-toolchain.toml'
        with:
          command: test
-      - run: rustup install ${{ matrix.toolchain }}
-        if: matrix.toolchain != 'rust-toolchain.toml'
-      - uses: actions-rs/cargo@v1
-        if: matrix.toolchain != 'rust-toolchain.toml'
-        with:
-          command: test
-          toolchain: ${{ matrix.toolchain }}

  test-os:
    name: Test Suite
    runs-on: ${{ matrix.os }}
    strategy:
-      fail-fast: false
      matrix:
+        # "windows-latest" was removed; see https://github.com/ZcashFoundation/zcash_script/issues/38
        os: [ubuntu-latest, macOS-latest, windows-latest]
    steps:
      - uses: actions/checkout@v4
@ -87,8 +85,19 @@ jobs:
      # - name: install LLVM on Mac
      #   if: matrix.os == 'macOS-latest'
      #   run: brew install llvm
-      - run: rustup target add x86_64-pc-windows-msvc
+      - uses: actions-rs/toolchain@v1
        if: matrix.os == 'windows-latest'
+        with:
+          target: x86_64-pc-windows-msvc
+          toolchain: stable
+          profile: minimal
+          override: true
+      - uses: actions-rs/toolchain@v1
+        if: matrix.os != 'windows-latest'
+        with:
+          toolchain: stable
+          profile: minimal
+          override: true
      - uses: actions-rs/cargo@v1
        if: matrix.os == 'windows-latest'
        with:
@ -102,34 +111,10 @@ jobs:
  fmt:
    name: Rustfmt
    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-      - uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
-
-  clippy:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-      - uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: -- -D warnings
-
-  fuzz:
-    name: Fuzz
-    runs-on: ubuntu-latest
    strategy:
      matrix:
        rust:
-          - nightly
+          - stable
    steps:
      - uses: actions/checkout@v4
        with:
@ -138,8 +123,29 @@ jobs:
        with:
          toolchain: ${{ matrix.rust }}
          override: true
-      - run: cargo install cargo-fuzz
+      - run: rustup component add rustfmt
      - uses: actions-rs/cargo@v1
        with:
-          command: fuzz
-          args: run compare -- -max_len=20000 -max_total_time=100
+          command: fmt
+          args: --all -- --check
+
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - stable
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
+      - run: rustup component add clippy
+      - uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: -- -D warnings
--- a/.github/workflows/dependencies.yml
+++ b/.github/workflows/dependencies.yml
@ -43,7 +43,7 @@ jobs:
      # this check also runs with optional features off
      # so we expect some warnings about "skip tree root was not found"
      - name: Check ${{ matrix.checks }} with features ${{ matrix.features }}
-        uses: EmbarkStudios/cargo-deny-action@v2
+        uses: EmbarkStudios/cargo-deny-action@v1
        with:
          command: check ${{ matrix.checks }}
          arguments: --workspace ${{ matrix.features }}
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -8,29 +8,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

 ## [Unreleased] - ReleaseDate

-## [0.3.1](https://github.com/ZcashFoundation/zcash_script/compare/v0.3.0...v0.3.1) - 2025-05-17
-
-### Other
-
- Remove extra `&` from `SighashCalculator` ([#216](https://github.com/ZcashFoundation/zcash_script/pull/216))
-
-## [0.3.0](https://github.com/ZcashFoundation/zcash_script/compare/v0.2.0...v0.3.0) - 2025-05-13
-
- Another major API update. The previous C++ functions were moved to the `cxx`
-  module. A new Rust implementation has been added. In the root of the
-  crate there are now "Intepreters" which allow choosing which implementation
-  to use.
-
- Eliminate `ScriptNum` ([#208](https://github.com/ZcashFoundation/zcash_script/pull/208))
- Add various stepwise functionality ([#204](https://github.com/ZcashFoundation/zcash_script/pull/204))
- Addressing post-hoc PR feedback on #174 ([#197](https://github.com/ZcashFoundation/zcash_script/pull/197))
- Expose `ScriptError` on C++ side ([#195](https://github.com/ZcashFoundation/zcash_script/pull/195))
- Change type of `lock_time` parameter ([#190](https://github.com/ZcashFoundation/zcash_script/pull/190))
- Initial Rust implementation ([#174](https://github.com/ZcashFoundation/zcash_script/pull/174))
- Add a basic rust-toolchain.toml ([#176](https://github.com/ZcashFoundation/zcash_script/pull/176))
- Address Str4d’s comments on #171 ([#175](https://github.com/ZcashFoundation/zcash_script/pull/175))
- Provide a Rustier wrapper for zcash_script ([#171](https://github.com/ZcashFoundation/zcash_script/pull/171))
-
 ## [0.2.0] - 2024-06-10

 - Major API update. Most functions have been removed and a new callback-based
--- a/Cargo.lock
+++ b/Cargo.lock
@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 4
+version = 3

 [[package]]
 name = "aho-corasick"
@ -11,34 +11,18 @@ dependencies = [
 "memchr",
 ]

-[[package]]
-name = "arbitrary"
-version = "1.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d5a26814d8dcb93b0e5a0ff3c6d80a8843bafb21b39e8e18a6f05471870e110"
-
-[[package]]
-name = "arrayvec"
-version = "0.7.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
-
-[[package]]
-name = "autocfg"
-version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
-
 [[package]]
 name = "bindgen"
-version = "0.71.1"
+version = "0.69.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5f58bf3d7db68cfbac37cfc485a8d711e87e064c3d0fe0435b92f7a407f9d6b3"
+checksum = "a00dc851838a2120612785d195287475a3ac45514741da670b735818822129a0"
 dependencies = [
 "bitflags",
 "cexpr",
 "clang-sys",
 "itertools",
+ "lazy_static",
+ "lazycell",
 "log",
 "prettyplease",
 "proc-macro2",
@ -47,69 +31,24 @@ dependencies = [
 "rustc-hash",
 "shlex",
 "syn",
-]
-
-[[package]]
-name = "bit-set"
-version = "0.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08807e080ed7f9d5433fa9b275196cfc35414f66a0c79d864dc51a0d825231a3"
-dependencies = [
- "bit-vec",
-]
-
-[[package]]
-name = "bit-vec"
-version = "0.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
-
-[[package]]
-name = "bitcoin-io"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b47c4ab7a93edb0c7198c5535ed9b52b63095f4e9b45279c6736cec4b856baf"
-
-[[package]]
-name = "bitcoin_hashes"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb18c03d0db0247e147a21a6faafd5a7eb851c743db062de72018b6b7e8e4d16"
-dependencies = [
- "bitcoin-io",
- "hex-conservative",
+ "which",
 ]

 [[package]]
 name = "bitflags"
-version = "2.8.0"
+version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f68f53c83ab957f72c32642f3868eec03eb974d1fb82e453128456482613d36"
-
-[[package]]
-name = "block-buffer"
-version = "0.10.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
-dependencies = [
- "generic-array",
-]
-
-[[package]]
-name = "byteorder"
-version = "1.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+checksum = "b4682ae6287fcf752ecaabbfcc7b6f9b72aa33933dc23a554d853aea8eea8635"

 [[package]]
 name = "cc"
-version = "1.2.11"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e4730490333d58093109dc02c23174c3f4d490998c3fed3cc8e82d57afedb9cf"
+checksum = "d32a725bc159af97c3e629873bb9f88fb8cf8a4867175f76dc987815ea07c83b"
 dependencies = [
 "jobserver",
 "libc",
- "shlex",
+ "once_cell",
 ]

 [[package]]
@ -138,91 +77,31 @@ dependencies = [
 "libloading",
 ]

-[[package]]
-name = "cpufeatures"
-version = "0.2.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51e852e6dc9a5bed1fae92dd2375037bf2b768725bf3be87811edee3249d09ad"
-dependencies = [
- "libc",
-]
-
-[[package]]
-name = "crypto-common"
-version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
-dependencies = [
- "generic-array",
- "typenum",
-]
-
-[[package]]
-name = "digest"
-version = "0.10.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
-dependencies = [
- "block-buffer",
- "crypto-common",
-]
-
 [[package]]
 name = "either"
-version = "1.13.0"
+version = "1.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
-
-[[package]]
-name = "enum_primitive"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be4551092f4d519593039259a9ed8daedf0da12e5109c5280338073eaeb81180"
-dependencies = [
- "num-traits 0.1.43",
-]
+checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"

 [[package]]
 name = "errno"
-version = "0.3.10"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33d852cb9b869c2a9b3df2f71a3074817f01e1844f839a144f5fcef059a4eb5d"
+checksum = "136526188508e25c6fef639d7927dfb3e0e3084488bf202267829cf7fc23dbdd"
 dependencies = [
+ "errno-dragonfly",
 "libc",
 "windows-sys",
 ]

 [[package]]
-name = "fastrand"
-version = "2.3.0"
+name = "errno-dragonfly"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
-
-[[package]]
-name = "fnv"
-version = "1.0.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
-
-[[package]]
-name = "generic-array"
-version = "0.14.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+checksum = "aa68f1b12764fab894d2755d2518754e71b4fd80ecfb822714a1206c2aab39bf"
 dependencies = [
- "typenum",
- "version_check",
-]
-
-[[package]]
-name = "getrandom"
-version = "0.2.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4567c8db10ae91089c99af84c68c38da3ec2f087c3f82960bcdbf3656b6f4d7"
-dependencies = [
- "cfg-if",
+ "cc",
 "libc",
- "wasi",
 ]

 [[package]]
@ -238,12 +117,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"

 [[package]]
-name = "hex-conservative"
-version = "0.2.1"
+name = "home"
+version = "0.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5313b072ce3c597065a808dbf612c4c8e8590bdbf8b579508bf7a762c5eae6cd"
+checksum = "5444c27eef6923071f7ebcc33e3444508466a76f7a2b93da00ed6e19f30c1ddb"
 dependencies = [
- "arrayvec",
+ "windows-sys",
 ]

 [[package]]
@ -266,25 +145,21 @@ dependencies = [

 [[package]]
 name = "lazy_static"
-version = "1.5.0"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
+name = "lazycell"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"

 [[package]]
 name = "libc"
-version = "0.2.168"
+version = "0.2.148"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aaeb2981e0606ca11d79718f8bb01164f1d6ed75080182d3abf017e6d244b6d"
-
-[[package]]
-name = "libfuzzer-sys"
-version = "0.4.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf78f52d400cf2d84a3a973a78a592b4adc535739e0a5597a0da6f0c357adc75"
-dependencies = [
- "arbitrary",
- "cc",
-]
+checksum = "9cdc71e17332e86d2e1d38c1f99edcb6288ee11b815fb1a4b049eaa2114d369b"

 [[package]]
 name = "libloading"
@ -298,9 +173,9 @@ dependencies = [

 [[package]]
 name = "linux-raw-sys"
-version = "0.4.15"
+version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d26c52dbd32dccf2d10cac7725f8eae5296885fb5703b261f7d0a0739ec807ab"
+checksum = "1a9bad9f94746442c783ca431b22403b519cd7fbeed0533fdd6328b2f2212128"

 [[package]]
 name = "log"
@ -330,45 +205,12 @@ dependencies = [
 "minimal-lexical",
 ]

-[[package]]
-name = "num-traits"
-version = "0.1.43"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92e5113e9fd4cc14ded8e499429f396a20f98c772a47cc8622a736e1ec843c31"
-dependencies = [
- "num-traits 0.2.19",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.2.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "once_cell"
 version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"

-[[package]]
-name = "pin-project-lite"
-version = "0.2.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "915a1e146535de9163f3987b8944ed8cf49a18bb0056bcebcdcece385cece4ff"
-
-[[package]]
-name = "ppv-lite86"
-version = "0.2.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77957b295656769bb8ad2b6a6b09d897d94f05c41b069aede1fcdaa675eaea04"
-dependencies = [
- "zerocopy",
-]
-
 [[package]]
 name = "prettyplease"
 version = "0.2.15"
@ -381,39 +223,13 @@ dependencies = [

 [[package]]
 name = "proc-macro2"
-version = "1.0.93"
+version = "1.0.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60946a68e5f9d28b0dc1c21bb8a97ee7d018a8b322fa57838ba31cc878e22d99"
+checksum = "e835ff2298f5721608eb1a980ecaee1aef2c132bf95ecc026a11b7bf3c01c02e"
 dependencies = [
 "unicode-ident",
 ]

-[[package]]
-name = "proptest"
-version = "1.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "14cae93065090804185d3b75f0bf93b8eeda30c7a9b4a33d3bdb3988d6229e50"
-dependencies = [
- "bit-set",
- "bit-vec",
- "bitflags",
- "lazy_static",
- "num-traits 0.2.19",
- "rand",
- "rand_chacha",
- "rand_xorshift",
- "regex-syntax 0.8.5",
- "rusty-fork",
- "tempfile",
- "unarray",
-]
-
-[[package]]
-name = "quick-error"
-version = "1.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
-
 [[package]]
 name = "quote"
 version = "1.0.36"
@ -423,45 +239,6 @@ dependencies = [
 "proc-macro2",
 ]

-[[package]]
-name = "rand"
-version = "0.8.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
-dependencies = [
- "libc",
- "rand_chacha",
- "rand_core",
-]
-
-[[package]]
-name = "rand_chacha"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
-dependencies = [
- "ppv-lite86",
- "rand_core",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.6.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
-dependencies = [
- "getrandom",
-]
-
-[[package]]
-name = "rand_xorshift"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d25bf25ec5ae4a3f1b92f929810509a2f53d7dca2f50b794ff57e3face536c8f"
-dependencies = [
- "rand_core",
-]
-
 [[package]]
 name = "regex"
 version = "1.9.5"
@ -471,7 +248,7 @@ dependencies = [
 "aho-corasick",
 "memchr",
 "regex-automata",
- "regex-syntax 0.7.5",
+ "regex-syntax",
 ]

 [[package]]
@ -482,7 +259,7 @@ checksum = "c2f401f4955220693b56f8ec66ee9c78abffd8d1c4f23dc41a23839eb88f0795"
 dependencies = [
 "aho-corasick",
 "memchr",
- "regex-syntax 0.7.5",
+ "regex-syntax",
 ]

 [[package]]
@ -491,32 +268,17 @@ version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dbb5fb1acd8a1a18b3dd5be62d25485eb770e05afb408a9627d14d451bae12da"

-[[package]]
-name = "regex-syntax"
-version = "0.8.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
-
-[[package]]
-name = "ripemd"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd124222d17ad93a644ed9d011a40f4fb64aa54275c08cc216524a9ea82fb09f"
-dependencies = [
- "digest",
-]
-
 [[package]]
 name = "rustc-hash"
-version = "2.1.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7fb8039b3032c191086b10f11f319a6e99e1e82889c5cc6046f515c9db1d497"
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"

 [[package]]
 name = "rustix"
-version = "0.38.44"
+version = "0.38.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
+checksum = "d7db8590df6dfcd144d22afd1b83b36c21a18d7cbc1dc4bb5295a8712e9eb662"
 dependencies = [
 "bitflags",
 "errno",
@ -525,65 +287,11 @@ dependencies = [
 "windows-sys",
 ]

-[[package]]
-name = "rusty-fork"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cb3dcc6e454c328bb824492db107ab7c0ae8fcffe4ad210136ef014458c1bc4f"
-dependencies = [
- "fnv",
- "quick-error",
- "tempfile",
- "wait-timeout",
-]
-
-[[package]]
-name = "secp256k1"
-version = "0.30.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b50c5943d326858130af85e049f2661ba3c78b26589b8ab98e65e80ae44a1252"
-dependencies = [
- "bitcoin_hashes",
- "rand",
- "secp256k1-sys",
-]
-
-[[package]]
-name = "secp256k1-sys"
-version = "0.10.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1433bd67156263443f14d603720b082dd3121779323fce20cba2aa07b874bc1b"
-dependencies = [
- "cc",
-]
-
-[[package]]
-name = "sha-1"
-version = "0.10.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f5058ada175748e33390e40e872bd0fe59a19f265d0158daa551c5a88a76009c"
-dependencies = [
- "cfg-if",
- "cpufeatures",
- "digest",
-]
-
-[[package]]
-name = "sha2"
-version = "0.10.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "793db75ad2bcafc3ffa7c68b215fee268f537982cd901d132f89c6343f3a3dc8"
-dependencies = [
- "cfg-if",
- "cpufeatures",
- "digest",
-]
-
 [[package]]
 name = "shlex"
-version = "1.3.0"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+checksum = "a7cee0529a6d40f580e7a5e6c495c8fbfe21b7b52795ed4bb5e62cdf92bc6380"

 [[package]]
 name = "syn"
@ -596,62 +304,6 @@ dependencies = [
 "unicode-ident",
 ]

-[[package]]
-name = "tempfile"
-version = "3.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0f2c9fc62d0beef6951ccffd757e241266a2c833136efbe35af6cd2567dca5b"
-dependencies = [
- "cfg-if",
- "fastrand",
- "once_cell",
- "rustix",
- "windows-sys",
-]
-
-[[package]]
-name = "tracing"
-version = "0.1.41"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
-dependencies = [
- "pin-project-lite",
- "tracing-attributes",
- "tracing-core",
-]
-
-[[package]]
-name = "tracing-attributes"
-version = "0.1.28"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "395ae124c09f9e6918a2310af6038fba074bcf474ac352496d5910dd59a2226d"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "tracing-core"
-version = "0.1.33"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e672c95779cf947c5311f83787af4fa8fffd12fb27e4993211a84bdfd9610f9c"
-dependencies = [
- "once_cell",
-]
-
-[[package]]
-name = "typenum"
-version = "1.17.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
-
-[[package]]
-name = "unarray"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eaea85b334db583fe3274d12b4cd1880032beab409c0d774be044d4480ab9a94"
-
 [[package]]
 name = "unicode-ident"
 version = "1.0.12"
@ -659,26 +311,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"

 [[package]]
-name = "version_check"
-version = "0.9.5"
+name = "which"
+version = "4.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
-
-[[package]]
-name = "wait-timeout"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+checksum = "87ba24419a2078cd2b0f2ede2691b6c66d8e47836da3b6db8265ebad47afbfc7"
 dependencies = [
- "libc",
+ "either",
+ "home",
+ "once_cell",
+ "rustix",
 ]

-[[package]]
-name = "wasi"
-version = "0.11.0+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
-
 [[package]]
 name = "winapi"
 version = "0.3.9"
@ -703,23 +346,22 @@ checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

 [[package]]
 name = "windows-sys"
-version = "0.59.0"
+version = "0.48.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
 dependencies = [
 "windows-targets",
 ]

 [[package]]
 name = "windows-targets"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+checksum = "9a2fa6e2155d7247be68c096456083145c183cbbbc2764150dda45a87197940c"
 dependencies = [
 "windows_aarch64_gnullvm",
 "windows_aarch64_msvc",
 "windows_i686_gnu",
- "windows_i686_gnullvm",
 "windows_i686_msvc",
 "windows_x86_64_gnu",
 "windows_x86_64_gnullvm",
@ -728,88 +370,52 @@ dependencies = [

 [[package]]
 name = "windows_aarch64_gnullvm"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"

 [[package]]
 name = "windows_aarch64_msvc"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+checksum = "dc35310971f3b2dbbf3f0690a219f40e2d9afcf64f9ab7cc1be722937c26b4bc"

 [[package]]
 name = "windows_i686_gnu"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
-
-[[package]]
-name = "windows_i686_gnullvm"
-version = "0.52.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+checksum = "a75915e7def60c94dcef72200b9a8e58e5091744960da64ec734a6c6e9b3743e"

 [[package]]
 name = "windows_i686_msvc"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+checksum = "8f55c233f70c4b27f66c523580f78f1004e8b5a8b659e05a4eb49d4166cca406"

 [[package]]
 name = "windows_x86_64_gnu"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+checksum = "53d40abd2583d23e4718fddf1ebec84dbff8381c07cae67ff7768bbf19c6718e"

 [[package]]
 name = "windows_x86_64_gnullvm"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+checksum = "0b7b52767868a23d5bab768e390dc5f5c55825b6d30b86c844ff2dc7414044cc"

 [[package]]
 name = "windows_x86_64_msvc"
-version = "0.52.6"
+version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"

 [[package]]
 name = "zcash_script"
-version = "0.3.1"
+version = "0.2.0"
 dependencies = [
 "bindgen",
- "bitflags",
 "cc",
- "enum_primitive",
 "hex",
 "lazy_static",
- "libfuzzer-sys",
- "proptest",
- "ripemd",
- "secp256k1",
- "sha-1",
- "sha2",
- "tracing",
-]
-
-[[package]]
-name = "zerocopy"
-version = "0.7.35"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
-dependencies = [
- "byteorder",
- "zerocopy-derive",
-]
-
-[[package]]
-name = "zerocopy-derive"
-version = "0.7.35"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
 ]
--- a/Cargo.toml
+++ b/Cargo.toml
@ -1,12 +1,7 @@
 [package]
 name = "zcash_script"
-version = "0.3.1"
-authors = [
-    "Electric Coin Company <info@electriccoin.co>",
-    "Greg Pfeil <greg@technomadic.org>",
-    "Tamas Blummer <tamas.blummer@gmail.com>",
-    "Zcash Foundation <zebra@zfnd.org>",
-]
+version = "0.2.0"
+authors = ["Tamas Blummer <tamas.blummer@gmail.com>", "Zcash Foundation <zebra@zfnd.org>"]
 license = "Apache-2.0"
 readme = "README.md"
 build = "build.rs"
@ -20,7 +15,6 @@ include = [
    "/README.md",
    "build.rs",
    "src/*.rs",
-    "src/*/*.rs",
    "/depend/check_uint128_t.c",
    "/depend/zcash/src/amount.cpp",
    "/depend/zcash/src/amount.h",
@ -64,36 +58,28 @@ path = "src/lib.rs"

 [features]
 external-secp = []
-test-dependencies = []

 [dependencies]
-bitflags = "2.8"
-enum_primitive = "0.1"
-ripemd = "0.1"
-secp256k1 = "0.30"
-sha-1 = "0.10"
-sha2 = "0.10"
-tracing = "0.1"

 [build-dependencies]
-# We want zcash-script to be compatible with whatever version of `bindgen` that
-# is being indirectly used by Zebra via the `rocksdb` dependency. To avoid
-# having to update zcash-script every time Zebra updates its `rocksdb`
-# dependency, we allow any version of `bindgen`, even major version bumps, by
-# using the `>=` operator. There is some chance that this breaks the build if a
-# breaking API change affects us, but we can always fix it then.
-bindgen = ">= 0.69.5"
-# Same reasoning as above
-cc = { version = ">= 1.2.11", features = ["parallel"] }
+# The `bindgen` dependency should automatically upgrade to match the version used by zebra-state's `rocksdb` dependency in:
+# https://github.com/ZcashFoundation/zebra/blob/main/zebra-state/Cargo.toml
+#
+# Treat minor versions with a zero major version as compatible (cargo doesn't by default).
+bindgen = ">= 0.64.0"
+
+# These dependencies are shared with a lot of other Zebra dependencies,
+# so they are configured to automatically upgrade to match Zebra.
+# But we try to use the latest versions here, to catch any bugs in `zcash_script`'s CI.
+cc = { version = "1.0.94", features = ["parallel"] }

 [dev-dependencies]
-# Same reasoning as above
+# These dependencies are shared with a lot of other Zebra dependencies.
+# (See above.)
+#
+# Treat minor versions with a zero major version as compatible (cargo doesn't by default).
 hex = ">= 0.4.3"
-lazy_static = "1.5.0"
-proptest = "1.6"
-
-[target.'cfg(linux)'.dev-dependencies]
-libfuzzer-sys = "0.4"
+lazy_static = "1.4.0"

 [[package.metadata.release.pre-release-replacements]]
 file = "CHANGELOG.md"
--- a/build.rs
+++ b/build.rs
@ -23,10 +23,6 @@ impl fmt::Display for Error {

 impl std::error::Error for Error {}

-// `bindgen::RustTarget::Stable_*` is deprecated in bindgen >= 0.71.0, but we are constrained
-// downstream by the version supported by librocksdb-sys. However, one of our CI jobs still manages
-// to pull a newer version, so this silences the deprecation on that job.
-#[allow(deprecated)]
 fn bindgen_headers() -> Result<()> {
    println!("cargo:rerun-if-changed=depend/zcash/src/script/zcash_script.h");

@ -35,9 +31,6 @@ fn bindgen_headers() -> Result<()> {
        // Tell cargo to invalidate the built crate whenever any of the
        // included header files changed.
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
-        // This should not reference a version newer than rust-toolchain.toml. See
-        // rust-lang/rust-bindgen#3049 for a potential future solution.
-        .rust_target(bindgen::RustTarget::Stable_1_73)
        // Finish the builder and generate the bindings.
        .generate()
        .map_err(|_| Error::GenerateBindings)?;
@ -199,5 +192,5 @@ fn language_std(build: &mut cc::Build, std: &str) {
        "-std="
    };

-    build.flag([flag, std].concat());
+    build.flag(&[flag, std].concat());
 }
--- a/depend/zcash/src/script/script_error.h
+++ b/depend/zcash/src/script/script_error.h
@ -53,8 +53,6 @@ typedef enum ScriptError_t
    /* softfork safeness */
    SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS,

-    SCRIPT_ERR_VERIFY_SCRIPT,
-
    SCRIPT_ERR_ERROR_COUNT
 } ScriptError;

--- a/depend/zcash/src/script/zcash_script.cpp
+++ b/depend/zcash/src/script/zcash_script.cpp
@ -7,11 +7,10 @@
 #include "zcash_script.h"

 #include "script/interpreter.h"
-#include "script/script_error.h"
 #include "version.h"

 namespace {
-inline int set_error(ScriptError* ret, ScriptError serror)
+inline int set_error(zcash_script_error* ret, zcash_script_error serror)
 {
    if (ret)
        *ret = serror;
@ -43,10 +42,12 @@ int zcash_script_verify_callback(
    const unsigned char* scriptSig,
    unsigned int scriptSigLen,
    unsigned int flags,
-    ScriptError* script_err)
+    zcash_script_error* err)
 {
    try {
+        set_error(err, zcash_script_ERR_OK);
        CScriptNum nLockTimeNum = CScriptNum(nLockTime);
+        ScriptError script_err = SCRIPT_ERR_OK;
        return VerifyScript(
            CScript(scriptSig, scriptSig + scriptSigLen),
            CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen),
@ -55,8 +56,8 @@ int zcash_script_verify_callback(
            // consensusBranchId is not longer used with the callback API; the argument
            // was left there to minimize changes to interpreter.cpp
            0,
-            script_err);
+            &script_err);
    } catch (const std::exception&) {
-        return set_error(script_err, SCRIPT_ERR_VERIFY_SCRIPT);
+        return set_error(err, zcash_script_ERR_VERIFY_SCRIPT);
    }
 }
--- a/depend/zcash/src/script/zcash_script.h
+++ b/depend/zcash/src/script/zcash_script.h
@ -8,7 +8,6 @@
 #define ZCASH_SCRIPT_ZCASH_SCRIPT_H

 #include <stdint.h>
-#include "script_error.h"

 #if defined(BUILD_BITCOIN_INTERNAL) && defined(HAVE_CONFIG_H)
 #include "config/bitcoin-config.h"
@ -37,6 +36,19 @@ extern "C" {

 #define ZCASH_SCRIPT_API_VER 4

+typedef enum zcash_script_error_t
+{
+    zcash_script_ERR_OK = 0,
+    zcash_script_ERR_TX_INDEX,
+    zcash_script_ERR_TX_SIZE_MISMATCH,
+    zcash_script_ERR_TX_DESERIALIZE,
+    // Defined since API version 3.
+    zcash_script_ERR_TX_VERSION,
+    zcash_script_ERR_ALL_PREV_OUTPUTS_SIZE_MISMATCH,
+    zcash_script_ERR_ALL_PREV_OUTPUTS_DESERIALIZE,
+    zcash_script_ERR_VERIFY_SCRIPT,
+} zcash_script_error;
+
 /** Script verification flags */
 enum
 {
@ -81,7 +93,8 @@ EXPORT_SYMBOL unsigned int zcash_script_legacy_sigop_count_script(
 /// - flags: the script verification flags to use.
 /// - err: if not NULL, err will contain an error/success code for the operation.
 ///
-/// Note that script verification failure is indicated by a return value of 0.
+/// Note that script verification failure is indicated by err being set to
+/// zcash_script_ERR_OK and a return value of 0.
 EXPORT_SYMBOL int zcash_script_verify_callback(
    const void* ctx,
    void (*sighash)(unsigned char* sighash, unsigned int sighashLen, const void* ctx, const unsigned char* scriptCode, unsigned int scriptCodeLen, int hashType),
@ -92,7 +105,7 @@ EXPORT_SYMBOL int zcash_script_verify_callback(
    const unsigned char* scriptSig,
    unsigned int scriptSigLen,
    unsigned int flags,
-    ScriptError* err);
+    zcash_script_error* err);

 #ifdef __cplusplus
 } // extern "C"
--- a/fuzz/.gitignore
+++ b/fuzz/.gitignore
@ -1,4 +0,0 @@
-target
-corpus
-artifacts
-coverage
--- a/fuzz/Cargo.toml
+++ b/fuzz/Cargo.toml
@ -1,19 +0,0 @@
-[package]
-name = "zcash_script-fuzz"
-version = "0.0.0"
-publish = false
-edition = "2021"
-
-[package.metadata]
-cargo-fuzz = true
-
-[dependencies]
-libfuzzer-sys = "0.4"
-zcash_script = { path = "..", features = ["test-dependencies"] }
-
-[[bin]]
-name = "compare"
-path = "fuzz_targets/compare.rs"
-test = false
-doc = false
-bench = false
--- a/fuzz/fuzz_targets/compare.rs
+++ b/fuzz/fuzz_targets/compare.rs
@ -1,41 +0,0 @@
-#![no_main]
-
-use libfuzzer_sys::fuzz_target;
-extern crate zcash_script;
-
-use zcash_script::interpreter::CallbackTransactionSignatureChecker;
-use zcash_script::*;
-
-fn missing_sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
-    None
-}
-
-fuzz_target!(|tup: (u32, bool, &[u8], &[u8], u32)| {
-    // `fuzz_target!` doesn’t support pattern matching in the parameter list.
-    let (lock_time, is_final, pub_key, sig, flag_bits) = tup;
-    let flags = testing::repair_flags(VerificationFlags::from_bits_truncate(flag_bits));
-    let ret = check_verify_callback(
-        &CxxInterpreter {
-            sighash: &missing_sighash,
-            lock_time,
-            is_final,
-        },
-        &rust_interpreter(
-            flags,
-            CallbackTransactionSignatureChecker {
-                sighash: &missing_sighash,
-                lock_time: lock_time.into(),
-                is_final,
-            },
-        ),
-        pub_key,
-        sig,
-        flags,
-    );
-    assert_eq!(
-        ret.0,
-        ret.1.map_err(normalize_error),
-        "original Rust result: {:?}",
-        ret.1
-    );
-});
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@ -1,5 +0,0 @@
-[toolchain]
-# TODO: C++ linking on Linux broke in 1.82, but is fixed again in 1.85. This can be bumped once that
-#       is released.
-channel = "1.81"
-components = ["clippy", "rustfmt"]
--- a/src/cxx.rs
+++ b/src/cxx.rs
@ -1,114 +0,0 @@
-//! Rust bindings for Zcash transparent scripts.
-
-#![allow(missing_docs)]
-#![allow(clippy::needless_lifetimes)]
-#![allow(non_upper_case_globals)]
-#![allow(non_camel_case_types)]
-#![allow(non_snake_case)]
-#![allow(unsafe_code)]
-#![allow(unused_imports)]
-#![allow(clippy::unwrap_or_default)]
-
-// Use the generated C++ bindings
-include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
-#[cfg(test)]
-mod tests {
-    use std::ffi::{c_int, c_uint, c_void};
-
-    use hex::FromHex;
-
-    lazy_static::lazy_static! {
-        pub static ref SCRIPT_PUBKEY: Vec<u8> = <Vec<u8>>::from_hex("a914c117756dcbe144a12a7c33a77cfa81aa5aeeb38187").unwrap();
-        pub static ref SCRIPT_SIG: Vec<u8> = <Vec<u8>>::from_hex("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").expect("Block bytes are in valid hex representation");
-    }
-
-    extern "C" fn sighash(
-        sighash_out: *mut u8,
-        sighash_out_len: c_uint,
-        ctx: *const c_void,
-        _script_code: *const u8,
-        _script_code_len: c_uint,
-        _hash_type: c_int,
-    ) {
-        unsafe {
-            assert!(ctx.is_null());
-            let sighash =
-                hex::decode("e8c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-                    .unwrap();
-            assert!(sighash_out_len == sighash.len() as c_uint);
-            std::ptr::copy_nonoverlapping(sighash.as_ptr(), sighash_out, sighash.len());
-        }
-    }
-
-    extern "C" fn invalid_sighash(
-        sighash_out: *mut u8,
-        sighash_out_len: c_uint,
-        ctx: *const c_void,
-        _script_code: *const u8,
-        _script_code_len: c_uint,
-        _hash_type: c_int,
-    ) {
-        unsafe {
-            assert!(ctx.is_null());
-            let sighash =
-                hex::decode("08c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-                    .unwrap();
-            assert!(sighash_out_len == sighash.len() as c_uint);
-            std::ptr::copy_nonoverlapping(sighash.as_ptr(), sighash_out, sighash.len());
-        }
-    }
-
-    #[test]
-    fn it_works() {
-        let nLockTime: i64 = 2410374;
-        let isFinal: u8 = 1;
-        let script_pub_key = &*SCRIPT_PUBKEY;
-        let script_sig = &*SCRIPT_SIG;
-        let flags: c_uint = 513;
-        let mut err = 0;
-
-        let ret = unsafe {
-            super::zcash_script_verify_callback(
-                std::ptr::null(),
-                Some(sighash),
-                nLockTime,
-                isFinal,
-                script_pub_key.as_ptr(),
-                script_pub_key.len() as c_uint,
-                script_sig.as_ptr(),
-                script_sig.len() as c_uint,
-                flags,
-                &mut err,
-            )
-        };
-
-        assert!(ret == 1);
-    }
-
-    #[test]
-    fn it_fails_on_invalid_sighash() {
-        let nLockTime: i64 = 2410374;
-        let isFinal: u8 = 1;
-        let script_pub_key = &*SCRIPT_PUBKEY;
-        let script_sig = &*SCRIPT_SIG;
-        let flags: c_uint = 513;
-        let mut err = 0;
-
-        let ret = unsafe {
-            super::zcash_script_verify_callback(
-                std::ptr::null(),
-                Some(invalid_sighash),
-                nLockTime,
-                isFinal,
-                script_pub_key.as_ptr(),
-                script_pub_key.len() as c_uint,
-                script_sig.as_ptr(),
-                script_sig.len() as c_uint,
-                flags,
-                &mut err,
-            )
-        };
-
-        assert!(ret != 1);
-    }
-}
--- a/src/external/mod.rs
+++ b/src/external/mod.rs
@ -1,3 +0,0 @@
-//! Modules that parallel the C++ implementation, but which live outside the script directory.
-
-pub mod pubkey;
--- a/src/external/pubkey.rs
+++ b/src/external/pubkey.rs
@ -1,56 +0,0 @@
-use secp256k1::{ecdsa, Message, PublicKey, Secp256k1};
-
-/// FIXME: `PUBLIC_KEY_SIZE` is meant to be an upper bound, it seems. Maybe parameterize the type
-///        over the size.
-pub struct PubKey<'a>(pub &'a [u8]);
-
-impl PubKey<'_> {
-    pub const PUBLIC_KEY_SIZE: usize = 65;
-    pub const COMPRESSED_PUBLIC_KEY_SIZE: usize = 33;
-
-    /// Check syntactic correctness.
-    ///
-    /// Note that this is consensus critical as CheckSig() calls it!
-    pub fn is_valid(&self) -> bool {
-        !self.0.is_empty()
-    }
-
-    /// Verify a DER signature (~72 bytes).
-    /// If this public key is not fully valid, the return value will be false.
-    pub fn verify(&self, hash: &[u8; 32], vch_sig: &[u8]) -> bool {
-        if !self.is_valid() {
-            return false;
-        };
-
-        if let Ok(pubkey) = PublicKey::from_slice(self.0) {
-            // let sig: secp256k1_ecdsa_signature;
-            if vch_sig.is_empty() {
-                return false;
-            };
-            // Zcash, unlike Bitcoin, has always enforced strict DER signatures.
-            if let Ok(mut sig) = ecdsa::Signature::from_der(vch_sig) {
-                // libsecp256k1's ECDSA verification requires lower-S signatures, which have
-                // not historically been enforced in Bitcoin or Zcash, so normalize them first.
-                sig.normalize_s();
-                let secp = Secp256k1::verification_only();
-                secp.verify_ecdsa(&Message::from_digest(*hash), &sig, &pubkey)
-                    .is_ok()
-            } else {
-                false
-            }
-        } else {
-            false
-        }
-    }
-
-    pub fn check_low_s(vch_sig: &[u8]) -> bool {
-        /* Zcash, unlike Bitcoin, has always enforced strict DER signatures. */
-        if let Ok(sig) = ecdsa::Signature::from_der(vch_sig) {
-            let mut check = sig;
-            check.normalize_s();
-            sig == check
-        } else {
-            false
-        }
-    }
-}
--- a/src/interpreter.rs
+++ b/src/interpreter.rs
--- a/src/lib.rs
+++ b/src/lib.rs
@ -1,536 +1,117 @@
-//! Zcash transparent script implementations.
+//! Rust bindings for Zcash transparent scripts.

 #![doc(html_logo_url = "https://www.zfnd.org/images/zebra-icon.png")]
-#![doc(html_root_url = "https://docs.rs/zcash_script/0.3.0")]
+#![doc(html_root_url = "https://docs.rs/zcash_script/0.2.0")]
+#![allow(missing_docs)]
+#![allow(clippy::needless_lifetimes)]
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 #![allow(unsafe_code)]
-#[macro_use]
-extern crate enum_primitive;
-
-pub mod cxx;
-mod external;
-pub mod interpreter;
-mod script;
-pub mod script_error;
-mod zcash_script;
-
-use std::os::raw::{c_int, c_uint, c_void};
-
-use tracing::warn;
-
-pub use interpreter::{
-    CallbackTransactionSignatureChecker, DefaultStepEvaluator, HashType, SighashCalculator,
-    SignedOutputs, VerificationFlags,
-};
-use script_error::ScriptError;
-pub use zcash_script::*;
-
-pub struct CxxInterpreter<'a> {
-    pub sighash: SighashCalculator<'a>,
-    pub lock_time: u32,
-    pub is_final: bool,
-}
-
-impl From<cxx::ScriptError> for Error {
-    #[allow(non_upper_case_globals)]
-    fn from(err_code: cxx::ScriptError) -> Self {
-        match err_code {
-            cxx::ScriptError_t_SCRIPT_ERR_OK => Error::Ok(ScriptError::Ok),
-            cxx::ScriptError_t_SCRIPT_ERR_UNKNOWN_ERROR => Error::Ok(ScriptError::UnknownError),
-            cxx::ScriptError_t_SCRIPT_ERR_EVAL_FALSE => Error::Ok(ScriptError::EvalFalse),
-            cxx::ScriptError_t_SCRIPT_ERR_OP_RETURN => Error::Ok(ScriptError::OpReturn),
-
-            cxx::ScriptError_t_SCRIPT_ERR_SCRIPT_SIZE => Error::Ok(ScriptError::ScriptSize),
-            cxx::ScriptError_t_SCRIPT_ERR_PUSH_SIZE => Error::Ok(ScriptError::PushSize),
-            cxx::ScriptError_t_SCRIPT_ERR_OP_COUNT => Error::Ok(ScriptError::OpCount),
-            cxx::ScriptError_t_SCRIPT_ERR_STACK_SIZE => Error::Ok(ScriptError::StackSize),
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_COUNT => Error::Ok(ScriptError::SigCount),
-            cxx::ScriptError_t_SCRIPT_ERR_PUBKEY_COUNT => Error::Ok(ScriptError::PubKeyCount),
-
-            cxx::ScriptError_t_SCRIPT_ERR_VERIFY => Error::Ok(ScriptError::Verify),
-            cxx::ScriptError_t_SCRIPT_ERR_EQUALVERIFY => Error::Ok(ScriptError::EqualVerify),
-            cxx::ScriptError_t_SCRIPT_ERR_CHECKMULTISIGVERIFY => {
-                Error::Ok(ScriptError::CheckMultisigVerify)
-            }
-            cxx::ScriptError_t_SCRIPT_ERR_CHECKSIGVERIFY => Error::Ok(ScriptError::CheckSigVerify),
-            cxx::ScriptError_t_SCRIPT_ERR_NUMEQUALVERIFY => Error::Ok(ScriptError::NumEqualVerify),
-
-            cxx::ScriptError_t_SCRIPT_ERR_BAD_OPCODE => Error::Ok(ScriptError::BadOpcode),
-            cxx::ScriptError_t_SCRIPT_ERR_DISABLED_OPCODE => Error::Ok(ScriptError::DisabledOpcode),
-            cxx::ScriptError_t_SCRIPT_ERR_INVALID_STACK_OPERATION => {
-                Error::Ok(ScriptError::InvalidStackOperation)
-            }
-            cxx::ScriptError_t_SCRIPT_ERR_INVALID_ALTSTACK_OPERATION => {
-                Error::Ok(ScriptError::InvalidAltstackOperation)
-            }
-            cxx::ScriptError_t_SCRIPT_ERR_UNBALANCED_CONDITIONAL => {
-                Error::Ok(ScriptError::UnbalancedConditional)
-            }
-
-            cxx::ScriptError_t_SCRIPT_ERR_NEGATIVE_LOCKTIME => {
-                Error::Ok(ScriptError::NegativeLockTime)
-            }
-            cxx::ScriptError_t_SCRIPT_ERR_UNSATISFIED_LOCKTIME => {
-                Error::Ok(ScriptError::UnsatisfiedLockTime)
-            }
-
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_HASHTYPE => Error::Ok(ScriptError::SigHashType),
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_DER => Error::Ok(ScriptError::SigDER),
-            cxx::ScriptError_t_SCRIPT_ERR_MINIMALDATA => Error::Ok(ScriptError::MinimalData),
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_PUSHONLY => Error::Ok(ScriptError::SigPushOnly),
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_HIGH_S => Error::Ok(ScriptError::SigHighS),
-            cxx::ScriptError_t_SCRIPT_ERR_SIG_NULLDUMMY => Error::Ok(ScriptError::SigNullDummy),
-            cxx::ScriptError_t_SCRIPT_ERR_PUBKEYTYPE => Error::Ok(ScriptError::PubKeyType),
-            cxx::ScriptError_t_SCRIPT_ERR_CLEANSTACK => Error::Ok(ScriptError::CleanStack),
-
-            cxx::ScriptError_t_SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS => {
-                Error::Ok(ScriptError::DiscourageUpgradableNOPs)
-            }
-
-            cxx::ScriptError_t_SCRIPT_ERR_VERIFY_SCRIPT => Error::VerifyScript,
-            unknown => Error::Unknown(unknown.into()),
-        }
-    }
-}
-
-/// The sighash callback to use with zcash_script.
-extern "C" fn sighash_callback(
-    sighash_out: *mut u8,
-    sighash_out_len: c_uint,
-    ctx: *const c_void,
-    script_code: *const u8,
-    script_code_len: c_uint,
-    hash_type: c_int,
-) {
-    let checked_script_code_len = usize::try_from(script_code_len)
-        .expect("This was converted from a `usize` in the first place");
-    // SAFETY: `script_code` is created from a Rust slice in `verify_callback`, passed through the
-    // C++ code, eventually to `CallbackTransactionSignatureChecker::CheckSig`, which calls this
-    // function.
-    let script_code_vec =
-        unsafe { std::slice::from_raw_parts(script_code, checked_script_code_len) };
-    // SAFETY: `ctx` is a valid `SighashCalculator` constructed in `verify_callback`
-    // which forwards it to the `CallbackTransactionSignatureChecker`.
-    let callback = unsafe { *(ctx as *const SighashCalculator) };
-    // We don’t need to handle strictness here, because it is checked (when necessary) by
-    // `CheckSignatureEncoding` before `CallbackTransactionSignatureChecker` calls this callback.
-    // And we don’t have access to the flags here to determine if it should be checked.
-    if let Some(sighash) = HashType::from_bits(hash_type, false)
-        .ok()
-        .and_then(|ht| callback(script_code_vec, ht))
-    {
-        assert_eq!(sighash_out_len, sighash.len().try_into().unwrap());
-        // SAFETY: `sighash_out` is a valid buffer created in
-        // `CallbackTransactionSignatureChecker::CheckSig`.
-        unsafe { std::ptr::copy_nonoverlapping(sighash.as_ptr(), sighash_out, sighash.len()) };
-    }
-}
-
-/// This steals a bit of the wrapper code from zebra_script, to provide the API that they want.
-impl<'a> ZcashScript for CxxInterpreter<'a> {
-    fn verify_callback(
-        &self,
-        script_pub_key: &[u8],
-        signature_script: &[u8],
-        flags: VerificationFlags,
-    ) -> Result<(), Error> {
-        let mut err = 0;
-
-        // SAFETY: The `script` fields are created from a valid Rust `slice`.
-        let ret = unsafe {
-            cxx::zcash_script_verify_callback(
-                (&self.sighash as *const SighashCalculator) as *const c_void,
-                Some(sighash_callback),
-                self.lock_time.into(),
-                if self.is_final { 1 } else { 0 },
-                script_pub_key.as_ptr(),
-                script_pub_key
-                    .len()
-                    .try_into()
-                    .map_err(Error::InvalidScriptSize)?,
-                signature_script.as_ptr(),
-                signature_script
-                    .len()
-                    .try_into()
-                    .map_err(Error::InvalidScriptSize)?,
-                flags.bits(),
-                &mut err,
-            )
-        };
-
-        if ret == 1 {
-            Ok(())
-        } else {
-            Err(Error::from(err))
-        }
-    }
-
-    /// Returns the number of transparent signature operations in the
-    /// transparent inputs and outputs of this transaction.
-    fn legacy_sigop_count_script(&self, script: &[u8]) -> Result<u32, Error> {
-        script
-            .len()
-            .try_into()
-            .map_err(Error::InvalidScriptSize)
-            .map(|script_len| unsafe {
-                cxx::zcash_script_legacy_sigop_count_script(script.as_ptr(), script_len)
-            })
-    }
-}
-
-/// Runs both the C++ and Rust implementations `ZcashScript::legacy_sigop_count_script` and returns
-/// both results. This is more useful for testing than the impl that logs a warning if the results
-/// differ and always returns the C++ result.
-fn check_legacy_sigop_count_script<T: ZcashScript, U: ZcashScript>(
-    first: &T,
-    second: &U,
-    script: &[u8],
-) -> (Result<u32, Error>, Result<u32, Error>) {
-    (
-        first.legacy_sigop_count_script(script),
-        second.legacy_sigop_count_script(script),
-    )
-}
-
-/// Runs two implementations of `ZcashScript::verify_callback` with the same arguments and returns
-/// both results. This is more useful for testing than the impl that logs a warning if the results
-/// differ and always returns the `T` result.
-pub fn check_verify_callback<T: ZcashScript, U: ZcashScript>(
-    first: &T,
-    second: &U,
-    script_pub_key: &[u8],
-    script_sig: &[u8],
-    flags: VerificationFlags,
-) -> (Result<(), Error>, Result<(), Error>) {
-    (
-        first.verify_callback(script_pub_key, script_sig, flags),
-        second.verify_callback(script_pub_key, script_sig, flags),
-    )
-}
-
-/// Convert errors that don’t exist in the C++ code into the cases that do.
-pub fn normalize_error(err: Error) -> Error {
-    match err {
-        Error::Ok(serr) => Error::Ok(match serr {
-            ScriptError::ReadError { .. } => ScriptError::BadOpcode,
-            ScriptError::ScriptNumError(_) => ScriptError::UnknownError,
-            _ => serr,
-        }),
-        _ => err,
-    }
-}
-
-/// A tag to indicate that both the C++ and Rust implementations of zcash_script should be used,
-/// with their results compared.
-pub struct ComparisonInterpreter<T, U> {
-    first: T,
-    second: U,
-}
-
-pub fn cxx_rust_comparison_interpreter(
-    sighash: SighashCalculator,
-    lock_time: u32,
-    is_final: bool,
-    flags: VerificationFlags,
-) -> ComparisonInterpreter<
-    CxxInterpreter,
-    StepwiseInterpreter<DefaultStepEvaluator<CallbackTransactionSignatureChecker>>,
-> {
-    ComparisonInterpreter {
-        first: CxxInterpreter {
-            sighash,
-            lock_time,
-            is_final,
-        },
-        second: rust_interpreter(
-            flags,
-            CallbackTransactionSignatureChecker {
-                sighash,
-                lock_time: lock_time.into(),
-                is_final,
-            },
-        ),
-    }
-}
-
-/// This implementation is functionally equivalent to the `T` impl, but it also runs a second (`U`)
-/// impl and logs a warning if they disagree.
-impl<T: ZcashScript, U: ZcashScript> ZcashScript for ComparisonInterpreter<T, U> {
-    fn legacy_sigop_count_script(&self, script: &[u8]) -> Result<u32, Error> {
-        let (cxx, rust) = check_legacy_sigop_count_script(&self.first, &self.second, script);
-        if rust != cxx {
-            warn!(
-                "The Rust Zcash Script interpreter had a different sigop count ({:?}) from the C++ one ({:?}).",
-                rust,
-                cxx)
-        };
-        cxx
-    }
-
-    fn verify_callback(
-        &self,
-        script_pub_key: &[u8],
-        script_sig: &[u8],
-        flags: VerificationFlags,
-    ) -> Result<(), Error> {
-        let (cxx, rust) =
-            check_verify_callback(&self.first, &self.second, script_pub_key, script_sig, flags);
-        if rust.map_err(normalize_error) != cxx {
-            // probably want to distinguish between
-            // - one succeeding when the other fails (bad), and
-            // - differing error codes (maybe not bad).
-            warn!(
-                "The Rust Zcash Script interpreter had a different result ({:?}) from the C++ one ({:?}).",
-                rust,
-                cxx)
-        };
-        cxx
-    }
-}
-
-#[cfg(any(test, feature = "test-dependencies"))]
-pub mod testing {
-    use super::*;
-    use crate::{
-        interpreter::{State, StepFn},
-        script::{Operation, Script},
-    };
-
-    /// Ensures that flags represent a supported state. This avoids crashes in the C++ code, which
-    /// break various tests.
-    pub fn repair_flags(flags: VerificationFlags) -> VerificationFlags {
-        // TODO: The C++ implementation fails an assert (interpreter.cpp:1097) if `CleanStack` is
-        //       set without `P2SH`.
-        if flags.contains(VerificationFlags::CleanStack) {
-            flags & VerificationFlags::P2SH
-        } else {
-            flags
-        }
-    }
-
-    /// A `usize` one larger than the longest allowed script, for testing bounds.
-    pub const OVERFLOW_SCRIPT_SIZE: usize = script::MAX_SCRIPT_SIZE + 1;
-
-    /// This is the same as `DefaultStepEvaluator`, except that it skips `OP_EQUAL`, allowing us to
-    /// test comparison failures.
-    #[derive(Copy, Clone, Debug, PartialEq, Eq)]
-    pub struct BrokenStepEvaluator<T>(pub T);
-
-    impl<T: StepFn> StepFn for BrokenStepEvaluator<T> {
-        type Payload = T::Payload;
-        fn call<'a>(
-            &self,
-            pc: &'a [u8],
-            script: &Script,
-            state: &mut State,
-            payload: &mut T::Payload,
-        ) -> Result<&'a [u8], ScriptError> {
-            self.0.call(
-                if pc[0] == Operation::OP_EQUAL.into() {
-                    &pc[1..]
-                } else {
-                    pc
-                },
-                script,
-                state,
-                payload,
-            )
-        }
-    }
-}
+#![allow(unused_imports)]
+#![allow(clippy::unwrap_or_default)]

+// Use the generated C++ bindings
+include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
 #[cfg(test)]
 mod tests {
-    use super::{testing::*, *};
+    use std::ffi::{c_int, c_uint, c_void};
+
+    pub use super::zcash_script_error_t;
    use hex::FromHex;
-    use proptest::prelude::*;

    lazy_static::lazy_static! {
        pub static ref SCRIPT_PUBKEY: Vec<u8> = <Vec<u8>>::from_hex("a914c117756dcbe144a12a7c33a77cfa81aa5aeeb38187").unwrap();
        pub static ref SCRIPT_SIG: Vec<u8> = <Vec<u8>>::from_hex("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").expect("Block bytes are in valid hex representation");
    }

-    fn sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
+    extern "C" fn sighash(
+        sighash_out: *mut u8,
+        sighash_out_len: c_uint,
+        ctx: *const c_void,
+        _script_code: *const u8,
+        _script_code_len: c_uint,
+        _hash_type: c_int,
+    ) {
+        unsafe {
+            assert!(ctx.is_null());
+            let sighash =
                hex::decode("e8c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-            .unwrap()
-            .as_slice()
-            .first_chunk::<32>()
-            .copied()
+                    .unwrap();
+            assert!(sighash_out_len == sighash.len() as c_uint);
+            std::ptr::copy_nonoverlapping(sighash.as_ptr(), sighash_out, sighash.len());
+        }
    }

-    fn invalid_sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
+    extern "C" fn invalid_sighash(
+        sighash_out: *mut u8,
+        sighash_out_len: c_uint,
+        ctx: *const c_void,
+        _script_code: *const u8,
+        _script_code_len: c_uint,
+        _hash_type: c_int,
+    ) {
+        unsafe {
+            assert!(ctx.is_null());
+            let sighash =
                hex::decode("08c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-            .unwrap()
-            .as_slice()
-            .first_chunk::<32>()
-            .copied()
+                    .unwrap();
+            assert!(sighash_out_len == sighash.len() as c_uint);
+            std::ptr::copy_nonoverlapping(sighash.as_ptr(), sighash_out, sighash.len());
        }
-
-    fn missing_sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
-        None
    }

    #[test]
    fn it_works() {
-        let lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
+        let nLockTime: i64 = 2410374;
+        let isFinal: u8 = 1;
+        let script_pub_key = &*SCRIPT_PUBKEY;
+        let script_sig = &*SCRIPT_SIG;
+        let flags: c_uint = 513;
+        let mut err = 0;

-        let ret = check_verify_callback(
-            &CxxInterpreter {
-                sighash: &sighash,
-                lock_time,
-                is_final,
-            },
-            &rust_interpreter(
+        let ret = unsafe {
+            super::zcash_script_verify_callback(
+                std::ptr::null(),
+                Some(sighash),
+                nLockTime,
+                isFinal,
+                script_pub_key.as_ptr(),
+                script_pub_key.len() as c_uint,
+                script_sig.as_ptr(),
+                script_sig.len() as c_uint,
                flags,
-                CallbackTransactionSignatureChecker {
-                    sighash: &sighash,
-                    lock_time: lock_time.into(),
-                    is_final,
-                },
-            ),
-            script_pub_key,
-            script_sig,
-            flags,
-        );
+                &mut err,
+            )
+        };

-        assert_eq!(ret.0, ret.1.map_err(normalize_error));
-        assert!(ret.0.is_ok());
+        assert!(ret == 1);
    }

    #[test]
    fn it_fails_on_invalid_sighash() {
-        let lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-        let ret = check_verify_callback(
-            &CxxInterpreter {
-                sighash: &invalid_sighash,
-                lock_time,
-                is_final,
-            },
-            &rust_interpreter(
-                flags,
-                CallbackTransactionSignatureChecker {
-                    sighash: &invalid_sighash,
-                    lock_time: lock_time.into(),
-                    is_final,
-                },
-            ),
-            script_pub_key,
-            script_sig,
-            flags,
-        );
+        let nLockTime: i64 = 2410374;
+        let isFinal: u8 = 1;
+        let script_pub_key = &*SCRIPT_PUBKEY;
+        let script_sig = &*SCRIPT_SIG;
+        let flags: c_uint = 513;
+        let mut err = 0;

-        assert_eq!(ret.0, ret.1.map_err(normalize_error));
-        assert_eq!(ret.0, Err(Error::Ok(ScriptError::EvalFalse)));
-    }
-
-    #[test]
-    fn it_fails_on_missing_sighash() {
-        let lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-
-        let ret = check_verify_callback(
-            &CxxInterpreter {
-                sighash: &missing_sighash,
-                lock_time,
-                is_final,
-            },
-            &rust_interpreter(
+        let ret = unsafe {
+            super::zcash_script_verify_callback(
+                std::ptr::null(),
+                Some(invalid_sighash),
+                nLockTime,
+                isFinal,
+                script_pub_key.as_ptr(),
+                script_pub_key.len() as c_uint,
+                script_sig.as_ptr(),
+                script_sig.len() as c_uint,
                flags,
-                CallbackTransactionSignatureChecker {
-                    sighash: &missing_sighash,
-                    lock_time: lock_time.into(),
-                    is_final,
-                },
-            ),
-            script_pub_key,
-            script_sig,
-            flags,
-        );
+                &mut err,
+            )
+        };

-        assert_eq!(ret.0, ret.1.map_err(normalize_error));
-        assert_eq!(ret.0, Err(Error::Ok(ScriptError::EvalFalse)));
-    }
-
-    proptest! {
-        #![proptest_config(ProptestConfig {
-            cases: 20_000, .. ProptestConfig::default()
-        })]
-
-        #[test]
-        fn test_arbitrary_scripts(
-            lock_time in prop::num::u32::ANY,
-            is_final in prop::bool::ANY,
-            pub_key in prop::collection::vec(0..=0xffu8, 0..=OVERFLOW_SCRIPT_SIZE),
-            sig in prop::collection::vec(0..=0xffu8, 1..=OVERFLOW_SCRIPT_SIZE),
-            flag_bits in prop::bits::u32::masked(VerificationFlags::all().bits()),
-        ) {
-            let flags = repair_flags(VerificationFlags::from_bits_truncate(flag_bits));
-            let ret = check_verify_callback(
-            &CxxInterpreter {
-                sighash: &sighash,
-                lock_time,
-                is_final,
-            },
-            &rust_interpreter(
-                flags,
-                CallbackTransactionSignatureChecker {
-                    sighash: &sighash,
-                    lock_time: lock_time.into(),
-                    is_final,
-                },
-            ),
-                &pub_key[..],
-                &sig[..],
-                flags,
-            );
-            prop_assert_eq!(ret.0, ret.1.map_err(normalize_error),
-                            "original Rust result: {:?}", ret.1);
-        }
-
-        /// Similar to `test_arbitrary_scripts`, but ensures the `sig` only contains pushes.
-        #[test]
-        fn test_restricted_sig_scripts(
-            lock_time in prop::num::u32::ANY,
-            is_final in prop::bool::ANY,
-            pub_key in prop::collection::vec(0..=0xffu8, 0..=OVERFLOW_SCRIPT_SIZE),
-            sig in prop::collection::vec(0..=0x60u8, 0..=OVERFLOW_SCRIPT_SIZE),
-            flag_bits in prop::bits::u32::masked(
-                // Don’t waste test cases on whether or not `SigPushOnly` is set.
-                (VerificationFlags::all() - VerificationFlags::SigPushOnly).bits()),
-        ) {
-            let flags = repair_flags(VerificationFlags::from_bits_truncate(flag_bits))
-                    | VerificationFlags::SigPushOnly;
-            let ret = check_verify_callback(
-            &CxxInterpreter {
-                sighash: &sighash,
-                lock_time,
-                is_final,
-            },
-            &rust_interpreter(
-                flags,
-                CallbackTransactionSignatureChecker {
-                    sighash: &sighash,
-                    lock_time: lock_time.into(),
-                    is_final,
-                },
-            ),
-                &pub_key[..],
-                &sig[..],
-                flags,
-            );
-            prop_assert_eq!(ret.0, ret.1.map_err(normalize_error),
-                            "original Rust result: {:?}", ret.1);
-        }
+        assert!(ret != 1);
    }
 }
--- a/src/script.rs
+++ b/src/script.rs
@ -1,489 +0,0 @@
-#![allow(non_camel_case_types)]
-
-use enum_primitive::FromPrimitive;
-
-use super::script_error::*;
-
-pub const MAX_SCRIPT_ELEMENT_SIZE: usize = 520; // bytes
-
-/// Maximum script length in bytes
-pub const MAX_SCRIPT_SIZE: usize = 10000;
-
-// Threshold for lock_time: below this value it is interpreted as block number,
-// otherwise as UNIX timestamp.
-pub const LOCKTIME_THRESHOLD: i64 = 500000000; // Tue Nov  5 00:53:20 1985 UTC
-
-/** Script opcodes */
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
-pub enum Opcode {
-    PushValue(PushValue),
-    Operation(Operation),
-}
-
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
-#[repr(u8)]
-pub enum PushValue {
-    // push value
-    OP_0 = 0x00,
-    PushdataBytelength(u8),
-    OP_PUSHDATA1 = 0x4c,
-    OP_PUSHDATA2 = 0x4d,
-    OP_PUSHDATA4 = 0x4e,
-    OP_1NEGATE = 0x4f,
-    OP_RESERVED = 0x50,
-    OP_1 = 0x51,
-    OP_2 = 0x52,
-    OP_3 = 0x53,
-    OP_4 = 0x54,
-    OP_5 = 0x55,
-    OP_6 = 0x56,
-    OP_7 = 0x57,
-    OP_8 = 0x58,
-    OP_9 = 0x59,
-    OP_10 = 0x5a,
-    OP_11 = 0x5b,
-    OP_12 = 0x5c,
-    OP_13 = 0x5d,
-    OP_14 = 0x5e,
-    OP_15 = 0x5f,
-    OP_16 = 0x60,
-}
-
-use PushValue::*;
-
-enum_from_primitive! {
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
-#[repr(u8)]
-pub enum Operation {
-    // control
-    OP_NOP = 0x61,
-    OP_VER = 0x62,
-    OP_IF = 0x63,
-    OP_NOTIF = 0x64,
-    OP_VERIF = 0x65,
-    OP_VERNOTIF = 0x66,
-    OP_ELSE = 0x67,
-    OP_ENDIF = 0x68,
-    OP_VERIFY = 0x69,
-    OP_RETURN = 0x6a,
-
-    // stack ops
-    OP_TOALTSTACK = 0x6b,
-    OP_FROMALTSTACK = 0x6c,
-    OP_2DROP = 0x6d,
-    OP_2DUP = 0x6e,
-    OP_3DUP = 0x6f,
-    OP_2OVER = 0x70,
-    OP_2ROT = 0x71,
-    OP_2SWAP = 0x72,
-    OP_IFDUP = 0x73,
-    OP_DEPTH = 0x74,
-    OP_DROP = 0x75,
-    OP_DUP = 0x76,
-    OP_NIP = 0x77,
-    OP_OVER = 0x78,
-    OP_PICK = 0x79,
-    OP_ROLL = 0x7a,
-    OP_ROT = 0x7b,
-    OP_SWAP = 0x7c,
-    OP_TUCK = 0x7d,
-
-    // splice ops
-    OP_CAT = 0x7e,
-    OP_SUBSTR = 0x7f,
-    OP_LEFT = 0x80,
-    OP_RIGHT = 0x81,
-    OP_SIZE = 0x82,
-
-    // bit logic
-    OP_INVERT = 0x83,
-    OP_AND = 0x84,
-    OP_OR = 0x85,
-    OP_XOR = 0x86,
-    OP_EQUAL = 0x87,
-    OP_EQUALVERIFY = 0x88,
-    OP_RESERVED1 = 0x89,
-    OP_RESERVED2 = 0x8a,
-
-    // numeric
-    OP_1ADD = 0x8b,
-    OP_1SUB = 0x8c,
-    OP_2MUL = 0x8d,
-    OP_2DIV = 0x8e,
-    OP_NEGATE = 0x8f,
-    OP_ABS = 0x90,
-    OP_NOT = 0x91,
-    OP_0NOTEQUAL = 0x92,
-
-    OP_ADD = 0x93,
-    OP_SUB = 0x94,
-    OP_MUL = 0x95,
-    OP_DIV = 0x96,
-    OP_MOD = 0x97,
-    OP_LSHIFT = 0x98,
-    OP_RSHIFT = 0x99,
-
-    OP_BOOLAND = 0x9a,
-    OP_BOOLOR = 0x9b,
-    OP_NUMEQUAL = 0x9c,
-    OP_NUMEQUALVERIFY = 0x9d,
-    OP_NUMNOTEQUAL = 0x9e,
-    OP_LESSTHAN = 0x9f,
-    OP_GREATERTHAN = 0xa0,
-    OP_LESSTHANOREQUAL = 0xa1,
-    OP_GREATERTHANOREQUAL = 0xa2,
-    OP_MIN = 0xa3,
-    OP_MAX = 0xa4,
-
-    OP_WITHIN = 0xa5,
-
-    // crypto
-    OP_RIPEMD160 = 0xa6,
-    OP_SHA1 = 0xa7,
-    OP_SHA256 = 0xa8,
-    OP_HASH160 = 0xa9,
-    OP_HASH256 = 0xaa,
-    OP_CODESEPARATOR = 0xab,
-    OP_CHECKSIG = 0xac,
-    OP_CHECKSIGVERIFY = 0xad,
-    OP_CHECKMULTISIG = 0xae,
-    OP_CHECKMULTISIGVERIFY = 0xaf,
-
-    // expansion
-    OP_NOP1 = 0xb0,
-    OP_CHECKLOCKTIMEVERIFY = 0xb1,
-    OP_NOP3 = 0xb2,
-    OP_NOP4 = 0xb3,
-    OP_NOP5 = 0xb4,
-    OP_NOP6 = 0xb5,
-    OP_NOP7 = 0xb6,
-    OP_NOP8 = 0xb7,
-    OP_NOP9 = 0xb8,
-    OP_NOP10 = 0xb9,
-
-    OP_INVALIDOPCODE = 0xff,
-}
-}
-
-use Operation::*;
-
-impl From<Opcode> for u8 {
-    fn from(value: Opcode) -> Self {
-        match value {
-            Opcode::PushValue(pv) => pv.into(),
-            Opcode::Operation(op) => op.into(),
-        }
-    }
-}
-
-impl From<u8> for Opcode {
-    fn from(value: u8) -> Self {
-        Operation::from_u8(value).map_or(
-            PushValue::try_from(value)
-                .map_or(Opcode::Operation(OP_INVALIDOPCODE), Opcode::PushValue),
-            Opcode::Operation,
-        )
-    }
-}
-
-impl From<PushValue> for u8 {
-    fn from(value: PushValue) -> Self {
-        match value {
-            OP_0 => 0x00,
-            PushdataBytelength(byte) => byte,
-            OP_PUSHDATA1 => 0x4c,
-            OP_PUSHDATA2 => 0x4d,
-            OP_PUSHDATA4 => 0x4e,
-            OP_1NEGATE => 0x4f,
-            OP_RESERVED => 0x50,
-            OP_1 => 0x51,
-            OP_2 => 0x52,
-            OP_3 => 0x53,
-            OP_4 => 0x54,
-            OP_5 => 0x55,
-            OP_6 => 0x56,
-            OP_7 => 0x57,
-            OP_8 => 0x58,
-            OP_9 => 0x59,
-            OP_10 => 0x5a,
-            OP_11 => 0x5b,
-            OP_12 => 0x5c,
-            OP_13 => 0x5d,
-            OP_14 => 0x5e,
-            OP_15 => 0x5f,
-            OP_16 => 0x60,
-        }
-    }
-}
-
-impl TryFrom<u8> for PushValue {
-    type Error = ();
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        match value {
-            0x00 => Ok(OP_0),
-            0x4c => Ok(OP_PUSHDATA1),
-            0x4d => Ok(OP_PUSHDATA2),
-            0x4e => Ok(OP_PUSHDATA4),
-            0x4f => Ok(OP_1NEGATE),
-            0x50 => Ok(OP_RESERVED),
-            0x51 => Ok(OP_1),
-            0x52 => Ok(OP_2),
-            0x53 => Ok(OP_3),
-            0x54 => Ok(OP_4),
-            0x55 => Ok(OP_5),
-            0x56 => Ok(OP_6),
-            0x57 => Ok(OP_7),
-            0x58 => Ok(OP_8),
-            0x59 => Ok(OP_9),
-            0x5a => Ok(OP_10),
-            0x5b => Ok(OP_11),
-            0x5c => Ok(OP_12),
-            0x5d => Ok(OP_13),
-            0x5e => Ok(OP_14),
-            0x5f => Ok(OP_15),
-            0x60 => Ok(OP_16),
-            _ => {
-                if value <= 0x60 {
-                    Ok(PushdataBytelength(value))
-                } else {
-                    Err(())
-                }
-            }
-        }
-    }
-}
-
-impl From<Operation> for u8 {
-    fn from(value: Operation) -> Self {
-        // This is how you get the discriminant, but using `as` everywhere is too much code smell
-        value as u8
-    }
-}
-
-const DEFAULT_MAX_NUM_SIZE: usize = 4;
-
-pub fn parse_num(
-    vch: &Vec<u8>,
-    require_minimal: bool,
-    max_num_size: Option<usize>,
-) -> Result<i64, ScriptNumError> {
-    match vch.last() {
-        None => Ok(0),
-        Some(vch_back) => {
-            let max_num_size = max_num_size.unwrap_or(DEFAULT_MAX_NUM_SIZE);
-            if vch.len() > max_num_size {
-                return Err(ScriptNumError::Overflow {
-                    max_num_size,
-                    actual: vch.len(),
-                });
-            }
-            if require_minimal {
-                // Check that the number is encoded with the minimum possible number of bytes.
-                //
-                // If the most-significant-byte - excluding the sign bit - is zero then we're not
-                // minimal. Note how this test also rejects the negative-zero encoding, 0x80.
-                if (vch_back & 0x7F) == 0 {
-                    // One exception: if there's more than one byte and the most significant bit of
-                    // the second-most-significant-byte is set then it would have conflicted with
-                    // the sign bit if one fewer byte were used, and so such encodings are minimal.
-                    // An example of this is +-255, which have minimal encodings [0xff, 0x00] and
-                    // [0xff, 0x80] respectively.
-                    if vch.len() <= 1 || (vch[vch.len() - 2] & 0x80) == 0 {
-                        return Err(ScriptNumError::NonMinimalEncoding);
-                    }
-                }
-            }
-
-            if *vch == vec![0, 0, 0, 0, 0, 0, 0, 128, 128] {
-                // Match the behaviour of the C++ code, which special-cased this encoding to avoid
-                // an undefined shift of a signed type by 64 bits.
-                return Ok(i64::MIN);
-            };
-
-            // Ensure defined behaviour (in Rust, left shift of `i64` by 64 bits is an arithmetic
-            // overflow that may panic or give an unspecified result). The above encoding of
-            // `i64::MIN` is the only allowed 9-byte encoding.
-            if vch.len() > 8 {
-                return Err(ScriptNumError::Overflow {
-                    max_num_size: 8,
-                    actual: vch.len(),
-                });
-            };
-
-            let mut result: i64 = 0;
-            for (i, vch_i) in vch.iter().enumerate() {
-                result |= i64::from(*vch_i) << (8 * i);
-            }
-
-            // If the input vector's most significant byte is 0x80, remove it from the result's msb
-            // and return a negative.
-            if vch_back & 0x80 != 0 {
-                return Ok(-(result & !(0x80 << (8 * (vch.len() - 1)))));
-            };
-
-            Ok(result)
-        }
-    }
-}
-
-pub fn serialize_num(value: i64) -> Vec<u8> {
-    if value == 0 {
-        return Vec::new();
-    }
-
-    if value == i64::MIN {
-        // The code below was based on buggy C++ code, that produced the "wrong" result for
-        // INT64_MIN. In that case we intentionally return the result that the C++ code as compiled
-        // for zcashd (with `-fwrapv`) originally produced on an x86_64 system.
-        return vec![0, 0, 0, 0, 0, 0, 0, 128, 128];
-    }
-
-    let mut result = Vec::new();
-    let neg = value < 0;
-    let mut absvalue = value.abs();
-
-    while absvalue != 0 {
-        result.push(
-            (absvalue & 0xff)
-                .try_into()
-                .unwrap_or_else(|_| unreachable!()),
-        );
-        absvalue >>= 8;
-    }
-
-    // - If the most significant byte is >= 0x80 and the value is positive, push a new zero-byte to
-    //   make the significant byte < 0x80 again.
-    // - If the most significant byte is >= 0x80 and the value is negative, push a new 0x80 byte
-    //   that will be popped off when converting to an integral.
-    // - If the most significant byte is < 0x80 and the value is negative, add 0x80 to it, since it
-    //   will be subtracted and interpreted as a negative when converting to an integral.
-
-    if result.last().map_or(true, |last| last & 0x80 != 0) {
-        result.push(if neg { 0x80 } else { 0 });
-    } else if neg {
-        if let Some(last) = result.last_mut() {
-            *last |= 0x80;
-        }
-    }
-
-    result
-}
-
-/** Serialized script, used inside transaction inputs and outputs */
-#[derive(Clone, Debug)]
-pub struct Script<'a>(pub &'a [u8]);
-
-impl Script<'_> {
-    pub fn get_op(script: &[u8]) -> Result<(Opcode, &[u8]), ScriptError> {
-        Self::get_op2(script).map(|(op, _, remainder)| (op, remainder))
-    }
-
-    fn split_value(script: &[u8], needed_bytes: usize) -> Result<(&[u8], &[u8]), ScriptError> {
-        script
-            .split_at_checked(needed_bytes)
-            .ok_or(ScriptError::ReadError {
-                expected_bytes: needed_bytes,
-                available_bytes: script.len(),
-            })
-    }
-
-    /// First splits `size_size` bytes to determine the size of the value to read, then splits the
-    /// value.
-    fn split_tagged_value(script: &[u8], size_size: usize) -> Result<(&[u8], &[u8]), ScriptError> {
-        Script::split_value(script, size_size).and_then(|(bytes, script)| {
-            let mut size = 0;
-            for byte in bytes.iter().rev() {
-                size <<= 8;
-                size |= usize::from(*byte);
-            }
-            Script::split_value(script, size)
-        })
-    }
-
-    pub fn get_op2(script: &[u8]) -> Result<(Opcode, &[u8], &[u8]), ScriptError> {
-        match script.split_first() {
-            None => Err(ScriptError::ReadError {
-                expected_bytes: 1,
-                available_bytes: 0,
-            }),
-            Some((leading_byte, script)) => match Opcode::from(*leading_byte) {
-                op @ Opcode::PushValue(pv) => match pv {
-                    OP_PUSHDATA1 => Script::split_tagged_value(script, 1),
-                    OP_PUSHDATA2 => Script::split_tagged_value(script, 2),
-                    OP_PUSHDATA4 => Script::split_tagged_value(script, 4),
-                    PushdataBytelength(size_byte) => Script::split_value(script, size_byte.into()),
-                    _ => Ok((&[][..], script)),
-                }
-                .map(|(value, script)| (op, value, script)),
-                op => Ok((op, &[], script)),
-            },
-        }
-    }
-
-    /** Encode/decode small integers: */
-    pub fn decode_op_n(opcode: PushValue) -> u32 {
-        if opcode == OP_0 {
-            return 0;
-        }
-        assert!(opcode >= OP_1 && opcode <= OP_16);
-        (u8::from(opcode) - (u8::from(OP_1) - 1)).into()
-    }
-
-    /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
-    /// as 20 sigops. With pay-to-script-hash, that changed:
-    /// CHECKMULTISIGs serialized in script_sigs are
-    /// counted more accurately, assuming they are of the form
-    ///  ... OP_N CHECKMULTISIG ...
-    pub fn get_sig_op_count(&self, accurate: bool) -> u32 {
-        let mut n = 0;
-        let mut pc = self.0;
-        let mut last_opcode = Opcode::Operation(OP_INVALIDOPCODE);
-        while !pc.is_empty() {
-            let (opcode, new_pc) = match Self::get_op(pc) {
-                Ok(o) => o,
-                // Stop counting when we get to an invalid opcode.
-                Err(_) => break,
-            };
-            pc = new_pc;
-            if let Opcode::Operation(op) = opcode {
-                if op == OP_CHECKSIG || op == OP_CHECKSIGVERIFY {
-                    n += 1;
-                } else if op == OP_CHECKMULTISIG || op == OP_CHECKMULTISIGVERIFY {
-                    match last_opcode {
-                        Opcode::PushValue(pv) => {
-                            if accurate && pv >= OP_1 && pv <= OP_16 {
-                                n += Self::decode_op_n(pv);
-                            } else {
-                                n += 20
-                            }
-                        }
-                        _ => n += 20,
-                    }
-                }
-            }
-            last_opcode = opcode;
-        }
-        n
-    }
-
-    /// Returns true iff this script is P2SH.
-    pub fn is_pay_to_script_hash(&self) -> bool {
-        self.0.len() == 23
-            && self.0[0] == OP_HASH160.into()
-            && self.0[1] == 0x14
-            && self.0[22] == OP_EQUAL.into()
-    }
-
-    /// Called by `IsStandardTx` and P2SH/BIP62 VerifyScript (which makes it consensus-critical).
-    pub fn is_push_only(&self) -> bool {
-        let mut pc = self.0;
-        while !pc.is_empty() {
-            if let Ok((Opcode::PushValue(_), new_pc)) = Self::get_op(pc) {
-                pc = new_pc;
-            } else {
-                return false;
-            }
-        }
-        true
-    }
-}
--- a/src/script_error.rs
+++ b/src/script_error.rs
@ -1,67 +0,0 @@
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub enum ScriptNumError {
-    NonMinimalEncoding,
-    Overflow { max_num_size: usize, actual: usize },
-}
-
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-#[repr(i32)]
-pub enum ScriptError {
-    Ok = 0, // Unused (except in converting the C++ error to Rust)
-    UnknownError,
-    EvalFalse,
-    OpReturn,
-
-    // Max sizes
-    ScriptSize,
-    PushSize,
-    OpCount,
-    StackSize,
-    SigCount,
-    PubKeyCount,
-
-    // Failed verify operations
-    Verify,
-    EqualVerify,
-    CheckMultisigVerify,
-    CheckSigVerify,
-    NumEqualVerify,
-
-    // Logical/Format/Canonical errors
-    BadOpcode,
-    DisabledOpcode,
-    InvalidStackOperation,
-    InvalidAltstackOperation,
-    UnbalancedConditional,
-
-    // OP_CHECKLOCKTIMEVERIFY
-    NegativeLockTime,
-    UnsatisfiedLockTime,
-
-    // BIP62
-    SigHashType,
-    SigDER,
-    MinimalData,
-    SigPushOnly,
-    SigHighS,
-    SigNullDummy,
-    PubKeyType,
-    CleanStack,
-
-    // softfork safeness
-    DiscourageUpgradableNOPs,
-
-    ReadError {
-        expected_bytes: usize,
-        available_bytes: usize,
-    },
-
-    /// Corresponds to the `scriptnum_error` exception in C++.
-    ScriptNumError(ScriptNumError),
-}
-
-impl From<ScriptNumError> for ScriptError {
-    fn from(value: ScriptNumError) -> Self {
-        ScriptError::ScriptNumError(value)
-    }
-}
--- a/src/zcash_script.rs
+++ b/src/zcash_script.rs
@ -1,451 +0,0 @@
-use std::num::TryFromIntError;
-
-use super::interpreter::*;
-use super::script::*;
-use super::script_error::*;
-
-/// This maps to `zcash_script_error_t`, but most of those cases aren’t used any more. This only
-/// replicates the still-used cases, and then an `Unknown` bucket for anything else that might
-/// happen.
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub enum Error {
-    /// Any failure that results in the script being invalid.
-    Ok(ScriptError),
-    /// An exception was caught.
-    VerifyScript,
-    /// The script size can’t fit in a `u32`, as required by the C++ code.
-    InvalidScriptSize(TryFromIntError),
-    /// Some other failure value recovered from C++.
-    ///
-    /// __NB__: Linux uses `u32` for the underlying C++ enum while Windows uses `i32`, so `i64` can
-    ///         hold either.
-    Unknown(i64),
-}
-
-/// The external API of zcash_script. This is defined to make it possible to compare the C++ and
-/// Rust implementations.
-pub trait ZcashScript {
-    /// Returns `Ok(())` if the a transparent input correctly spends the matching output
-    ///  under the additional constraints specified by `flags`. This function
-    ///  receives only the required information to validate the spend and not
-    ///  the transaction itself. In particular, the sighash for the spend
-    ///  is obtained using a callback function.
-    ///
-    ///  - sighash: a callback function which is called to obtain the sighash.
-    ///  - lock_time: the lock time of the transaction being validated.
-    ///  - is_final: a boolean indicating whether the input being validated is final
-    ///    (i.e. its sequence number is 0xFFFFFFFF).
-    ///  - script_pub_key: the scriptPubKey of the output being spent.
-    ///  - script_sig: the scriptSig of the input being validated.
-    ///  - flags: the script verification flags to use.
-    ///
-    ///  Note that script verification failure is indicated by `Err(Error::Ok)`.
-    fn verify_callback(
-        &self,
-        script_pub_key: &[u8],
-        script_sig: &[u8],
-        flags: VerificationFlags,
-    ) -> Result<(), Error>;
-
-    /// Returns the number of transparent signature operations in the input or
-    /// output script pointed to by script.
-    fn legacy_sigop_count_script(&self, script: &[u8]) -> Result<u32, Error>;
-}
-
-pub fn stepwise_verify<F>(
-    script_pub_key: &[u8],
-    script_sig: &[u8],
-    flags: VerificationFlags,
-    payload: &mut F::Payload,
-    stepper: &F,
-) -> Result<(), Error>
-where
-    F: StepFn,
-{
-    verify_script(
-        &Script(script_sig),
-        &Script(script_pub_key),
-        flags,
-        payload,
-        stepper,
-    )
-    .map_err(Error::Ok)
-}
-
-/// A payload for comparing the results of two steppers.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct StepResults<T, U> {
-    /// This contains the step-wise states of the steppers as long as they were identical. Its
-    /// `head` contains the initial state and its `tail` has a 1:1 correspondence to the opcodes
-    /// (not to the bytes).
-    pub identical_states: Vec<State>,
-    /// If the execution matched the entire way, then this contains `None`. If there was a
-    /// divergence, then this contains `Some` with a pair of `Result`s – one representing each
-    /// stepper’s outcome at the point at which they diverged.
-    pub diverging_result: Option<(Result<State, ScriptError>, Result<State, ScriptError>)>,
-    /// The final payload of the first stepper.
-    pub payload_l: T,
-    /// The final payload of the second stepper.
-    pub payload_r: U,
-}
-
-impl<T, U> StepResults<T, U> {
-    pub fn initial(payload_l: T, payload_r: U) -> Self {
-        StepResults {
-            identical_states: vec![],
-            diverging_result: None,
-            payload_l,
-            payload_r,
-        }
-    }
-}
-
-/// This compares two `ZcashScript` implementations in a deep way – checking the entire `State` step
-/// by step. Note that this has some tradeoffs: one is performance. Another is that it doesn’t run
-/// the entire codepath of either implementation. The setup/wrapup code is specific to this
-/// definition, but any differences there should be caught very easily by other testing mechanisms
-/// (like `check_verify_callback`).
-///
-/// This returns a very debuggable result. See `StepResults` for details.
-pub struct ComparisonStepEvaluator<'a, T, U> {
-    pub eval_step_l: &'a dyn StepFn<Payload = T>,
-    pub eval_step_r: &'a dyn StepFn<Payload = U>,
-}
-
-impl<'a, T: Clone, U: Clone> StepFn for ComparisonStepEvaluator<'a, T, U> {
-    type Payload = StepResults<T, U>;
-    fn call<'b>(
-        &self,
-        pc: &'b [u8],
-        script: &Script,
-        state: &mut State,
-        payload: &mut StepResults<T, U>,
-    ) -> Result<&'b [u8], ScriptError> {
-        let mut right_state = (*state).clone();
-        let left = self
-            .eval_step_l
-            .call(pc, script, state, &mut payload.payload_l);
-        let right = self
-            .eval_step_r
-            .call(pc, script, &mut right_state, &mut payload.payload_r);
-
-        match (left, right) {
-            (Ok(_), Ok(_)) => {
-                if *state == right_state {
-                    payload.identical_states.push(state.clone());
-                    left
-                } else {
-                    // In this case, the script hasn’t failed, but we stop running
-                    // anything
-                    payload.diverging_result = Some((
-                        left.map(|_| state.clone()),
-                        right.map(|_| right_state.clone()),
-                    ));
-                    Err(ScriptError::UnknownError)
-                }
-            }
-            // at least one is `Err`
-            (_, _) => {
-                if left != right {
-                    payload.diverging_result = Some((
-                        left.map(|_| state.clone()),
-                        right.map(|_| right_state.clone()),
-                    ));
-                }
-                left.and(right)
-            }
-        }
-    }
-}
-
-pub struct StepwiseInterpreter<F>
-where
-    F: StepFn,
-{
-    initial_payload: F::Payload,
-    stepper: F,
-}
-
-impl<F: StepFn> StepwiseInterpreter<F> {
-    pub fn new(initial_payload: F::Payload, stepper: F) -> Self {
-        StepwiseInterpreter {
-            initial_payload,
-            stepper,
-        }
-    }
-}
-
-pub fn rust_interpreter<C: SignatureChecker + Copy>(
-    flags: VerificationFlags,
-    checker: C,
-) -> StepwiseInterpreter<DefaultStepEvaluator<C>> {
-    StepwiseInterpreter {
-        initial_payload: (),
-        stepper: DefaultStepEvaluator { flags, checker },
-    }
-}
-
-impl<F: StepFn> ZcashScript for StepwiseInterpreter<F> {
-    /// Returns the number of transparent signature operations in the
-    /// transparent inputs and outputs of this transaction.
-    fn legacy_sigop_count_script(&self, script: &[u8]) -> Result<u32, Error> {
-        let cscript = Script(script);
-        Ok(cscript.get_sig_op_count(false))
-    }
-
-    fn verify_callback(
-        &self,
-        script_pub_key: &[u8],
-        script_sig: &[u8],
-        flags: VerificationFlags,
-    ) -> Result<(), Error> {
-        let mut payload = self.initial_payload.clone();
-        stepwise_verify(
-            script_pub_key,
-            script_sig,
-            flags,
-            &mut payload,
-            &self.stepper,
-        )
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::testing::*;
-    use hex::FromHex;
-    use proptest::prelude::*;
-
-    lazy_static::lazy_static! {
-        pub static ref SCRIPT_PUBKEY: Vec<u8> = <Vec<u8>>::from_hex("a914c117756dcbe144a12a7c33a77cfa81aa5aeeb38187").unwrap();
-        pub static ref SCRIPT_SIG: Vec<u8> = <Vec<u8>>::from_hex("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").expect("Block bytes are in valid hex representation");
-    }
-
-    fn sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
-        hex::decode("e8c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-            .unwrap()
-            .as_slice()
-            .first_chunk::<32>()
-            .copied()
-    }
-
-    fn invalid_sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
-        hex::decode("08c7bdac77f6bb1f3aba2eaa1fada551a9c8b3b5ecd1ef86e6e58a5f1aab952c")
-            .unwrap()
-            .as_slice()
-            .first_chunk::<32>()
-            .copied()
-    }
-
-    fn missing_sighash(_script_code: &[u8], _hash_type: HashType) -> Option<[u8; 32]> {
-        None
-    }
-
-    #[test]
-    fn it_works() {
-        let n_lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-
-        let checker = CallbackTransactionSignatureChecker {
-            sighash: &sighash,
-            lock_time: n_lock_time.into(),
-            is_final,
-        };
-        let rust_stepper = DefaultStepEvaluator { flags, checker };
-        let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &rust_stepper,
-        };
-        let mut res = StepResults::initial((), ());
-        let ret = stepwise_verify(script_pub_key, script_sig, flags, &mut res, &stepper);
-
-        if res.diverging_result != None {
-            panic!("invalid result: {:?}", res);
-        }
-        assert_eq!(ret, Ok(()));
-    }
-
-    #[test]
-    fn broken_stepper_causes_divergence() {
-        let n_lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-
-        let checker = CallbackTransactionSignatureChecker {
-            sighash: &sighash,
-            lock_time: n_lock_time.into(),
-            is_final,
-        };
-        let rust_stepper = DefaultStepEvaluator { flags, checker };
-        let broken_stepper = BrokenStepEvaluator(rust_stepper);
-        let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &broken_stepper,
-        };
-        let mut res = StepResults::initial((), ());
-        let ret = stepwise_verify(script_pub_key, script_sig, flags, &mut res, &stepper);
-
-        // The final return value is from whichever stepper failed.
-        assert_eq!(
-            ret,
-            Err(Error::Ok(ScriptError::ReadError {
-                expected_bytes: 1,
-                available_bytes: 0,
-            }))
-        );
-
-        // `State`s are large, so we just check that there was some progress in lock step, and a
-        // divergence.
-        match res {
-            StepResults {
-                identical_states,
-                diverging_result:
-                    Some((
-                        Ok(state),
-                        Err(ScriptError::ReadError {
-                            expected_bytes: 1,
-                            available_bytes: 0,
-                        }),
-                    )),
-                payload_l: (),
-                payload_r: (),
-            } => {
-                assert!(
-                    identical_states.len() == 6
-                        && state.stack().size() == 4
-                        && state.altstack().empty()
-                        && state.op_count() == 2
-                        && state.vexec().empty()
-                );
-            }
-            _ => {
-                panic!("invalid result: {:?}", res);
-            }
-        }
-    }
-
-    #[test]
-    fn it_fails_on_invalid_sighash() {
-        let n_lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-
-        let checker = CallbackTransactionSignatureChecker {
-            sighash: &invalid_sighash,
-            lock_time: n_lock_time.into(),
-            is_final,
-        };
-        let rust_stepper = DefaultStepEvaluator { flags, checker };
-        let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &rust_stepper,
-        };
-        let mut res = StepResults::initial((), ());
-        let ret = stepwise_verify(script_pub_key, script_sig, flags, &mut res, &stepper);
-
-        if res.diverging_result != None {
-            panic!("mismatched result: {:?}", res);
-        }
-        assert_eq!(ret, Err(Error::Ok(ScriptError::EvalFalse)));
-    }
-
-    #[test]
-    fn it_fails_on_missing_sighash() {
-        let n_lock_time: u32 = 2410374;
-        let is_final: bool = true;
-        let script_pub_key = &SCRIPT_PUBKEY;
-        let script_sig = &SCRIPT_SIG;
-        let flags = VerificationFlags::P2SH | VerificationFlags::CHECKLOCKTIMEVERIFY;
-
-        let checker = CallbackTransactionSignatureChecker {
-            sighash: &missing_sighash,
-            lock_time: n_lock_time.into(),
-            is_final,
-        };
-        let rust_stepper = DefaultStepEvaluator { flags, checker };
-        let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &rust_stepper,
-        };
-        let mut res = StepResults::initial((), ());
-        let ret = stepwise_verify(script_pub_key, script_sig, flags, &mut res, &stepper);
-
-        if res.diverging_result != None {
-            panic!("mismatched result: {:?}", res);
-        }
-        assert_eq!(ret, Err(Error::Ok(ScriptError::EvalFalse)));
-    }
-
-    proptest! {
-        // The stepwise comparison tests are significantly slower than the simple comparison tests,
-        // so run fewer iterations.
-        #![proptest_config(ProptestConfig {
-            cases: 2_000, .. ProptestConfig::default()
-        })]
-
-        #[test]
-        fn test_arbitrary_scripts(
-            lock_time in prop::num::u32::ANY,
-            is_final in prop::bool::ANY,
-            pub_key in prop::collection::vec(0..=0xffu8, 0..=OVERFLOW_SCRIPT_SIZE),
-            sig in prop::collection::vec(0..=0xffu8, 1..=OVERFLOW_SCRIPT_SIZE),
-            flags in prop::bits::u32::masked(VerificationFlags::all().bits()),
-        ) {
-            let checker = CallbackTransactionSignatureChecker {
-                sighash: &missing_sighash,
-                lock_time: lock_time.into(),
-                is_final,
-            };
-            let flags = repair_flags(VerificationFlags::from_bits_truncate(flags));
-            let rust_stepper = DefaultStepEvaluator { flags, checker };
-            let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &rust_stepper,
-        };
-            let mut res = StepResults::initial((), ());
-            let _ = stepwise_verify(&pub_key[..], &sig[..], flags, &mut res, &stepper);
-
-            if res.diverging_result != None {
-                panic!("mismatched result: {:?}", res);
-            }
-        }
-
-        /// Similar to `test_arbitrary_scripts`, but ensures the `sig` only contains pushes.
-        #[test]
-        fn test_restricted_sig_scripts(
-            lock_time in prop::num::u32::ANY,
-            is_final in prop::bool::ANY,
-            pub_key in prop::collection::vec(0..=0xffu8, 0..=OVERFLOW_SCRIPT_SIZE),
-            sig in prop::collection::vec(0..=0x60u8, 0..=OVERFLOW_SCRIPT_SIZE),
-            flags in prop::bits::u32::masked(
-                // Don’t waste test cases on whether or not `SigPushOnly` is set.
-                (VerificationFlags::all() - VerificationFlags::SigPushOnly).bits()),
-        ) {
-            let checker = CallbackTransactionSignatureChecker {
-                sighash: &missing_sighash,
-                lock_time: lock_time.into(),
-                is_final,
-            };
-            let flags = repair_flags(VerificationFlags::from_bits_truncate(flags)) | VerificationFlags::SigPushOnly;
-            let rust_stepper = DefaultStepEvaluator { flags, checker };
-            let stepper = ComparisonStepEvaluator {
-            eval_step_l: &rust_stepper,
-            eval_step_r: &rust_stepper,
-        };
-            let mut res = StepResults::initial((), ());
-            let _ = stepwise_verify(&pub_key[..], &sig[..], flags, &mut res, &stepper);
-
-            if res.diverging_result != None {
-                panic!("mismatched result: {:?}", res);
-            }
-        }
-    }
-}