From 60f3f35d894ab74d591dff376ad4c8ce4f5557cb Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Fri, 24 Jan 2020 13:33:22 -0800
Subject: [PATCH] Refine Ed25519 byte arrays to ed25519-zebra types.

---
 Cargo.lock                               | 27 ++++++++++++++++++++++++
 zebra-chain/Cargo.toml                   |  4 +++-
 zebra-chain/src/transaction/joinsplit.rs |  7 ++----
 zebra-chain/src/transaction/serialize.rs | 26 ++++-------------------
 4 files changed, 36 insertions(+), 28 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 2fffc7476..d4ed3ad13 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -268,6 +268,19 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "245097e9a4535ee1e3e3931fcfcd55a796a44c643e8596ff6566d68f09b87bbc"
 
+[[package]]
+name = "curve25519-dalek"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26778518a7f6cffa1d25a44b602b62b979bd88adb9e99ffec546998cf3404839"
+dependencies = [
+ "byteorder",
+ "digest",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "darling"
 version = "0.10.2"
@@ -312,6 +325,19 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "ed25519-zebra"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dd3113b0008c4cc23688f2a0b9bbffe08d71ade8db480b43e1635c469e1f22b"
+dependencies = [
+ "curve25519-dalek",
+ "rand_core 0.5.1",
+ "serde",
+ "sha2",
+ "thiserror",
+]
+
 [[package]]
 name = "fake-simd"
 version = "0.1.2"
@@ -1644,6 +1670,7 @@ version = "0.1.0"
 dependencies = [
  "byteorder",
  "chrono",
+ "ed25519-zebra",
  "futures",
  "hex",
  "proptest",
diff --git a/zebra-chain/Cargo.toml b/zebra-chain/Cargo.toml
index ed3155faa..4e575cd07 100644
--- a/zebra-chain/Cargo.toml
+++ b/zebra-chain/Cargo.toml
@@ -13,8 +13,10 @@ byteorder = "1.3"
 chrono = "0.4"
 hex = "0.4"
 sha2 = "0.8"
-redjubjub = "0.1"
 futures = "0.3"
+# ZF deps
+redjubjub = "0.1"
+ed25519-zebra = "0.1"
 
 [dev-dependencies]
 proptest = "0.9"
diff --git a/zebra-chain/src/transaction/joinsplit.rs b/zebra-chain/src/transaction/joinsplit.rs
index 8ca6bc9ee..2ac7ea932 100644
--- a/zebra-chain/src/transaction/joinsplit.rs
+++ b/zebra-chain/src/transaction/joinsplit.rs
@@ -69,12 +69,9 @@ pub struct JoinSplitData<P: ZkSnarkProof> {
     /// all `JoinSplit`s.
     pub rest: Vec<JoinSplit<P>>,
     /// The public key for the JoinSplit signature.
-    // XXX refine to a Zcash-flavored Ed25519 pubkey.
-    pub pub_key: [u8; 32],
+    pub pub_key: ed25519_zebra::PublicKeyBytes,
     /// The JoinSplit signature.
-    // XXX refine to a Zcash-flavored Ed25519 signature.
-    // for now it's [u64; 8] rather than [u8; 64] to get trait impls
-    pub sig: [u64; 8],
+    pub sig: ed25519_zebra::Signature,
 }
 
 impl<P: ZkSnarkProof> JoinSplitData<P> {
diff --git a/zebra-chain/src/transaction/serialize.rs b/zebra-chain/src/transaction/serialize.rs
index 534d4dc0c..af578a034 100644
--- a/zebra-chain/src/transaction/serialize.rs
+++ b/zebra-chain/src/transaction/serialize.rs
@@ -125,18 +125,8 @@ impl<P: ZkSnarkProof> ZcashSerialize for JoinSplitData<P> {
         for joinsplit in self.joinsplits() {
             joinsplit.zcash_serialize(&mut writer)?;
         }
-        writer.write_all(&self.pub_key[..])?;
-        // XXX very ugly, this happens because we used a [u64; 8] instead of
-        // [u8; 64] to get trait impls and it will disappear when we refine to
-        // Zcash-flavored Ed25519.
-        writer.write_all(
-            &{
-                use byteorder::ByteOrder;
-                let mut bytes = [0u8; 64];
-                LittleEndian::write_u64_into(&self.sig[..], &mut bytes);
-                bytes
-            }[..],
-        )?;
+        writer.write_all(&<[u8; 32]>::from(self.pub_key)[..])?;
+        writer.write_all(&<[u8; 64]>::from(self.sig)[..])?;
         Ok(())
     }
 }
@@ -152,16 +142,8 @@ impl<P: ZkSnarkProof> ZcashDeserialize for Option<JoinSplitData<P>> {
                 for _ in 0..(n - 1) {
                     rest.push(JoinSplit::zcash_deserialize(&mut reader)?);
                 }
-                let pub_key = reader.read_32_bytes()?;
-                // XXX this is horrible, see above, will be removed with type refinement
-                let sig = {
-                    use byteorder::ByteOrder;
-                    let mut bytes = [0u8; 64];
-                    reader.read_exact(&mut bytes[..])?;
-                    let mut u64s = [0u64; 8];
-                    LittleEndian::read_u64_into(&bytes, &mut u64s[..]);
-                    u64s
-                };
+                let pub_key = reader.read_32_bytes()?.into();
+                let sig = reader.read_64_bytes()?.into();
                 Ok(Some(JoinSplitData {
                     first,
                     rest,