Build prover with byte arrays of params

zcash_proofs/src/lib.rs

@@ -135,7 +135,10 @@ pub fn load_parameters(
     )
 }
 
-fn parse_parameters<R: io::Read>(
+/// Parse Bls12 keys from bytes as serialized by [`Parameters::write`].
+///
+/// This function will panic if it encounters unparseable data.
+pub fn parse_parameters<R: io::Read>(
     spend_fs: R,
     output_fs: R,
     sprout_fs: Option<R>,

zcash_proofs/src/prover.rs

@@ -2,6 +2,7 @@
 
 use bellman::groth16::{Parameters, PreparedVerifyingKey};
 use bls12_381::Bls12;
+use std::path::Path;
 use zcash_primitives::{
     merkle_tree::MerklePath,
     primitives::{Diversifier, PaymentAddress, ProofGenerationKey, Rseed},
@@ -11,15 +12,10 @@ use zcash_primitives::{
     transaction::components::{Amount, GROTH_PROOF_SIZE},
 };
 
-use crate::sapling::SaplingProvingContext;
+use crate::{load_parameters, parse_parameters, sapling::SaplingProvingContext};
 
 #[cfg(feature = "local-prover")]
-use crate::{default_params_folder, load_parameters, SAPLING_OUTPUT_NAME, SAPLING_SPEND_NAME};
+use crate::{default_params_folder, SAPLING_OUTPUT_NAME, SAPLING_SPEND_NAME};
-#[cfg(feature = "local-prover")]
-use std::path::Path;
-
-#[cfg(feature = "bundled-prover")]
-use crate::parse_parameters;
 
 /// An implementation of [`TxProver`] using Sapling Spend and Output parameters from
 /// locally-accessible paths.
@@ -48,8 +44,6 @@ impl LocalTxProver {
     ///
     /// This function will panic if the paths do not point to valid parameter files with
     /// the expected hashes.
-    #[cfg(feature = "local-prover")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "local-prover")))]
     pub fn new(spend_path: &Path, output_path: &Path) -> Self {
         let (spend_params, spend_vk, output_params, _, _) =
             load_parameters(spend_path, output_path, None);
@@ -60,6 +54,32 @@ impl LocalTxProver {
         }
     }
 
+    /// Creates a `LocalTxProver` using parameters specified as byte arrays.
+    ///
+    /// # Examples
+    ///
+    /// ```should_panic
+    /// use std::path::Path;
+    /// use zcash_proofs::prover::LocalTxProver;
+    ///
+    /// let tx_prover = LocalTxProver::from_bytes(&[0u8], &[0u8]);
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the byte arrays do not contain valid parameters with
+    /// the expected hashes.
+    pub fn from_bytes(spend_param_bytes: &[u8], output_param_bytes: &[u8]) -> Self {
+        let (spend_params, spend_vk, output_params, _, _) =
+            parse_parameters(spend_param_bytes, output_param_bytes, None);
+
+        LocalTxProver {
+            spend_params,
+            spend_vk,
+            output_params,
+        }
+    }
+
     /// Attempts to create a `LocalTxProver` using parameters from the default local
     /// location.
     ///