Move Sprout proof logic into zcash_proofs

2025-01-30 15:32:14 +00:00 · 2019-11-06 08:58:42 +00:00 · 2019-11-06 08:58:42 +00:00 · d1bc61800c
commit d1bc61800c
parent de5943aea4
5 changed files with 222 additions and 137 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -362,7 +362,6 @@ dependencies = [
 "bellman 0.2.0",
 "blake2b_simd 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "blake2s_simd 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "ff 0.5.0",
 "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
--- a/librustzcash/Cargo.toml
+++ b/librustzcash/Cargo.toml
@ -27,7 +27,6 @@ ff = { version = "0.5.0", path = "../ff" }
 libc = "0.2"
 pairing = { version = "0.15.0", path = "../pairing" }
 lazy_static = "1"
-byteorder = "1"
 rand_core = "0.5.1"
 zcash_primitives = { version = "0.1.0", path = "../zcash_primitives" }
 zcash_proofs = { version = "0.1.0", path = "../zcash_proofs" }
--- a/librustzcash/src/rustzcash.rs
+++ b/librustzcash/src/rustzcash.rs
@ -15,12 +15,8 @@
 // See https://github.com/rust-lang/rfcs/pull/2585 for more background.
 #![allow(clippy::not_unsafe_ptr_arg_deref)]

-use bellman::{
-    gadgets::multipack,
-    groth16::{create_random_proof, verify_proof, Parameters, PreparedVerifyingKey, Proof},
-};
+use bellman::groth16::{Parameters, PreparedVerifyingKey, Proof};
 use blake2s_simd::Params as Blake2sParams;
-use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use ff::{PrimeField, PrimeFieldRepr};
 use lazy_static;
 use libc::{c_char, c_uchar, size_t};
@ -59,12 +55,10 @@ use zcash_primitives::{
    zip32, JUBJUB,
 };
 use zcash_proofs::{
-    circuit::{
-        sapling::TREE_DEPTH as SAPLING_TREE_DEPTH,
-        sprout::{self, TREE_DEPTH as SPROUT_TREE_DEPTH},
-    },
+    circuit::sapling::TREE_DEPTH as SAPLING_TREE_DEPTH,
    load_parameters,
    sapling::{SaplingProvingContext, SaplingVerificationContext},
+    sprout,
 };

 #[cfg(test)]
@ -759,14 +753,14 @@ pub extern "C" fn librustzcash_sprout_prove(
    in_value1: u64,
    in_rho1: *const [c_uchar; 32],
    in_r1: *const [c_uchar; 32],
-    in_auth1: *const [c_uchar; 1 + 33 * SPROUT_TREE_DEPTH + 8],
+    in_auth1: *const [c_uchar; sprout::WITNESS_PATH_SIZE],

    // Second input
    in_sk2: *const [c_uchar; 32],
    in_value2: u64,
    in_rho2: *const [c_uchar; 32],
    in_r2: *const [c_uchar; 32],
-    in_auth2: *const [c_uchar; 1 + 33 * SPROUT_TREE_DEPTH + 8],
+    in_auth2: *const [c_uchar; sprout::WITNESS_PATH_SIZE],

    // First output
    out_pk1: *const [c_uchar; 32],
@ -782,94 +776,6 @@ pub extern "C" fn librustzcash_sprout_prove(
    vpub_old: u64,
    vpub_new: u64,
 ) {
-    let phi = unsafe { *phi };
-    let rt = unsafe { *rt };
-    let h_sig = unsafe { *h_sig };
-    let in_sk1 = unsafe { *in_sk1 };
-    let in_rho1 = unsafe { *in_rho1 };
-    let in_r1 = unsafe { *in_r1 };
-    let in_auth1 = unsafe { *in_auth1 };
-    let in_sk2 = unsafe { *in_sk2 };
-    let in_rho2 = unsafe { *in_rho2 };
-    let in_r2 = unsafe { *in_r2 };
-    let in_auth2 = unsafe { *in_auth2 };
-    let out_pk1 = unsafe { *out_pk1 };
-    let out_r1 = unsafe { *out_r1 };
-    let out_pk2 = unsafe { *out_pk2 };
-    let out_r2 = unsafe { *out_r2 };
-
-    let mut inputs = Vec::with_capacity(2);
-    {
-        let mut handle_input = |sk, value, rho, r, mut auth: &[u8]| {
-            let value = Some(value);
-            let rho = Some(sprout::UniqueRandomness(rho));
-            let r = Some(sprout::CommitmentRandomness(r));
-            let a_sk = Some(sprout::SpendingKey(sk));
-
-            // skip the first byte
-            assert_eq!(auth[0], SPROUT_TREE_DEPTH as u8);
-            auth = &auth[1..];
-
-            let mut auth_path = [None; SPROUT_TREE_DEPTH];
-            for i in (0..SPROUT_TREE_DEPTH).rev() {
-                // skip length of inner vector
-                assert_eq!(auth[0], 32);
-                auth = &auth[1..];
-
-                let mut sibling = [0u8; 32];
-                sibling.copy_from_slice(&auth[0..32]);
-                auth = &auth[32..];
-
-                auth_path[i] = Some((sibling, false));
-            }
-
-            let mut position = auth
-                .read_u64::<LittleEndian>()
-                .expect("should have had index at the end");
-
-            for i in 0..SPROUT_TREE_DEPTH {
-                auth_path[i].as_mut().map(|p| p.1 = (position & 1) == 1);
-
-                position >>= 1;
-            }
-
-            inputs.push(sprout::JSInput {
-                value: value,
-                a_sk: a_sk,
-                rho: rho,
-                r: r,
-                auth_path: auth_path,
-            });
-        };
-
-        handle_input(in_sk1, in_value1, in_rho1, in_r1, &in_auth1[..]);
-        handle_input(in_sk2, in_value2, in_rho2, in_r2, &in_auth2[..]);
-    }
-
-    let mut outputs = Vec::with_capacity(2);
-    {
-        let mut handle_output = |a_pk, value, r| {
-            outputs.push(sprout::JSOutput {
-                value: Some(value),
-                a_pk: Some(sprout::PayingKey(a_pk)),
-                r: Some(sprout::CommitmentRandomness(r)),
-            });
-        };
-
-        handle_output(out_pk1, out_value1, out_r1);
-        handle_output(out_pk2, out_value2, out_r2);
-    }
-
-    let js = sprout::JoinSplit {
-        vpub_old: Some(vpub_old),
-        vpub_new: Some(vpub_new),
-        h_sig: Some(h_sig),
-        phi: Some(phi),
-        inputs: inputs,
-        outputs: outputs,
-        rt: Some(rt),
-    };
-
    // Load parameters from disk
    let sprout_fs = File::open(
        unsafe { &SPROUT_GROTH16_PARAMS_PATH }
@ -885,10 +791,30 @@ pub extern "C" fn librustzcash_sprout_prove(

    drop(sprout_fs);

-    // Initialize secure RNG
-    let mut rng = OsRng;
-
-    let proof = create_random_proof(js, &params, &mut rng).expect("proving should not fail");
+    let proof = sprout::create_proof(
+        unsafe { *phi },
+        unsafe { *rt },
+        unsafe { *h_sig },
+        unsafe { *in_sk1 },
+        in_value1,
+        unsafe { *in_rho1 },
+        unsafe { *in_r1 },
+        unsafe { &*in_auth1 },
+        unsafe { *in_sk2 },
+        in_value2,
+        unsafe { *in_rho2 },
+        unsafe { *in_r2 },
+        unsafe { &*in_auth2 },
+        unsafe { *out_pk1 },
+        out_value1,
+        unsafe { *out_r1 },
+        unsafe { *out_pk2 },
+        out_value2,
+        unsafe { *out_r2 },
+        vpub_old,
+        vpub_new,
+        &params,
+    );

    proof
        .write(&mut (unsafe { &mut *proof_out })[..])
@ -910,39 +836,20 @@ pub extern "C" fn librustzcash_sprout_verify(
    vpub_old: u64,
    vpub_new: u64,
 ) -> bool {
-    // Prepare the public input for the verifier
-    let mut public_input = Vec::with_capacity((32 * 8) + (8 * 2));
-    public_input.extend(unsafe { &(&*rt)[..] });
-    public_input.extend(unsafe { &(&*h_sig)[..] });
-    public_input.extend(unsafe { &(&*nf1)[..] });
-    public_input.extend(unsafe { &(&*mac1)[..] });
-    public_input.extend(unsafe { &(&*nf2)[..] });
-    public_input.extend(unsafe { &(&*mac2)[..] });
-    public_input.extend(unsafe { &(&*cm1)[..] });
-    public_input.extend(unsafe { &(&*cm2)[..] });
-    public_input.write_u64::<LittleEndian>(vpub_old).unwrap();
-    public_input.write_u64::<LittleEndian>(vpub_new).unwrap();
-
-    let public_input = multipack::bytes_to_bits(&public_input);
-    let public_input = multipack::compute_multipacking::<Bls12>(&public_input);
-
-    let proof = match Proof::read(unsafe { &(&*proof)[..] }) {
-        Ok(p) => p,
-        Err(_) => return false,
-    };
-
-    // Verify the proof
-    match verify_proof(
+    sprout::verify_proof(
+        unsafe { &*proof },
+        unsafe { &*rt },
+        unsafe { &*h_sig },
+        unsafe { &*mac1 },
+        unsafe { &*mac2 },
+        unsafe { &*nf1 },
+        unsafe { &*nf2 },
+        unsafe { &*cm1 },
+        unsafe { &*cm2 },
+        vpub_old,
+        vpub_new,
        unsafe { SPROUT_GROTH16_VK.as_ref() }.expect("parameters should have been initialized"),
-        &proof,
-        &public_input[..],
-    ) {
-        // No error, and proof verification successful
-        Ok(true) => true,
-
-        // Any other case
-        _ => false,
-    }
+    )
 }

 /// This function (using the proving context) constructs an Output proof given
--- a/zcash_proofs/src/lib.rs
+++ b/zcash_proofs/src/lib.rs
@ -15,6 +15,7 @@ use std::path::Path;
 pub mod circuit;
 mod hashreader;
 pub mod sapling;
+pub mod sprout;

 #[cfg(feature = "local-prover")]
 pub mod prover;
--- a/zcash_proofs/src/sprout.rs
+++ b/zcash_proofs/src/sprout.rs
@ -0,0 +1,179 @@
+//! APIs for creating and verifying Sprout proofs.
+
+use bellman::{
+    gadgets::multipack,
+    groth16::{self, create_random_proof, Parameters, PreparedVerifyingKey, Proof},
+};
+use pairing::bls12_381::Bls12;
+use rand_core::OsRng;
+
+use crate::circuit::sprout::*;
+
+const GROTH_PROOF_SIZE: usize = 48 // π_A
+    + 96 // π_B
+    + 48; // π_C
+pub const WITNESS_PATH_SIZE: usize = 1 + 33 * TREE_DEPTH + 8;
+
+/// Sprout JoinSplit proof generation.
+pub fn create_proof(
+    phi: [u8; 32],
+    rt: [u8; 32],
+    h_sig: [u8; 32],
+
+    // First input
+    in_sk1: [u8; 32],
+    in_value1: u64,
+    in_rho1: [u8; 32],
+    in_r1: [u8; 32],
+    in_auth1: &[u8; WITNESS_PATH_SIZE],
+
+    // Second input
+    in_sk2: [u8; 32],
+    in_value2: u64,
+    in_rho2: [u8; 32],
+    in_r2: [u8; 32],
+    in_auth2: &[u8; WITNESS_PATH_SIZE],
+
+    // First output
+    out_pk1: [u8; 32],
+    out_value1: u64,
+    out_r1: [u8; 32],
+
+    // Second output
+    out_pk2: [u8; 32],
+    out_value2: u64,
+    out_r2: [u8; 32],
+
+    // Public value
+    vpub_old: u64,
+    vpub_new: u64,
+
+    proving_key: &Parameters<Bls12>,
+) -> Proof<Bls12> {
+    let mut inputs = Vec::with_capacity(2);
+    {
+        let mut handle_input = |sk, value, rho, r, mut auth: &[u8]| {
+            let value = Some(value);
+            let rho = Some(UniqueRandomness(rho));
+            let r = Some(CommitmentRandomness(r));
+            let a_sk = Some(SpendingKey(sk));
+
+            // skip the first byte
+            assert_eq!(auth[0], TREE_DEPTH as u8);
+            auth = &auth[1..];
+
+            let mut auth_path = [None; TREE_DEPTH];
+            for i in (0..TREE_DEPTH).rev() {
+                // skip length of inner vector
+                assert_eq!(auth[0], 32);
+                auth = &auth[1..];
+
+                let mut sibling = [0u8; 32];
+                sibling.copy_from_slice(&auth[0..32]);
+                auth = &auth[32..];
+
+                auth_path[i] = Some((sibling, false));
+            }
+
+            let mut position = {
+                let mut bytes = [0; 8];
+                bytes.copy_from_slice(&auth[0..8]);
+                u64::from_le_bytes(bytes)
+            };
+
+            for entry in auth_path.iter_mut() {
+                if let Some(p) = entry {
+                    p.1 = (position & 1) == 1;
+                }
+
+                position >>= 1;
+            }
+
+            inputs.push(JSInput {
+                value,
+                a_sk,
+                rho,
+                r,
+                auth_path,
+            });
+        };
+
+        handle_input(in_sk1, in_value1, in_rho1, in_r1, &in_auth1[..]);
+        handle_input(in_sk2, in_value2, in_rho2, in_r2, &in_auth2[..]);
+    }
+
+    let mut outputs = Vec::with_capacity(2);
+    {
+        let mut handle_output = |a_pk, value, r| {
+            outputs.push(JSOutput {
+                value: Some(value),
+                a_pk: Some(PayingKey(a_pk)),
+                r: Some(CommitmentRandomness(r)),
+            });
+        };
+
+        handle_output(out_pk1, out_value1, out_r1);
+        handle_output(out_pk2, out_value2, out_r2);
+    }
+
+    let js = JoinSplit {
+        vpub_old: Some(vpub_old),
+        vpub_new: Some(vpub_new),
+        h_sig: Some(h_sig),
+        phi: Some(phi),
+        inputs,
+        outputs,
+        rt: Some(rt),
+    };
+
+    // Initialize secure RNG
+    let mut rng = OsRng;
+
+    create_random_proof(js, proving_key, &mut rng).expect("proving should not fail")
+}
+
+/// Sprout JoinSplit proof verification.
+pub fn verify_proof(
+    proof: &[u8; GROTH_PROOF_SIZE],
+    rt: &[u8; 32],
+    h_sig: &[u8; 32],
+    mac1: &[u8; 32],
+    mac2: &[u8; 32],
+    nf1: &[u8; 32],
+    nf2: &[u8; 32],
+    cm1: &[u8; 32],
+    cm2: &[u8; 32],
+    vpub_old: u64,
+    vpub_new: u64,
+    verifying_key: &PreparedVerifyingKey<Bls12>,
+) -> bool {
+    // Prepare the public input for the verifier
+    let mut public_input = Vec::with_capacity((32 * 8) + (8 * 2));
+    public_input.extend(rt);
+    public_input.extend(h_sig);
+    public_input.extend(nf1);
+    public_input.extend(mac1);
+    public_input.extend(nf2);
+    public_input.extend(mac2);
+    public_input.extend(cm1);
+    public_input.extend(cm2);
+    public_input.extend(&vpub_old.to_le_bytes());
+    public_input.extend(&vpub_new.to_le_bytes());
+
+    let public_input = multipack::bytes_to_bits(&public_input);
+    let public_input = multipack::compute_multipacking::<Bls12>(&public_input);
+
+    let proof = match Proof::read(&proof[..]) {
+        Ok(p) => p,
+        Err(_) => return false,
+    };
+
+    // Verify the proof
+    match groth16::verify_proof(verifying_key, &proof, &public_input[..]) {
+        // No error, and proof verification successful
+        Ok(true) => true,
+
+        // Any other case
+        _ => false,
+    }
+}