Implementation of SHA256.

This commit is contained in:
Sean Bowe 2018-03-15 13:08:12 -06:00
parent 75c5269d3b
commit ac13cb05bc
No known key found for this signature in database
GPG Key ID: 95684257D8F8B031
4 changed files with 422 additions and 0 deletions

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@ -24,6 +24,7 @@ rev = "7a5b5fc99ae483a0043db7547fb79a6fa44b88a9"
[dev-dependencies]
hex-literal = "0.1"
rust-crypto = "0.2"
[features]
default = ["u128-support"]

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@ -10,6 +10,7 @@ pub mod lookup;
pub mod ecc;
pub mod pedersen_hash;
pub mod multipack;
pub mod sha256;
pub mod sapling;

417
src/circuit/sha256.rs Normal file
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@ -0,0 +1,417 @@
use super::uint32::UInt32;
use super::multieq::MultiEq;
use super::boolean::Boolean;
use bellman::{ConstraintSystem, SynthesisError};
use pairing::Engine;
const ROUND_CONSTANTS: [u32; 64] = [
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
];
const IV: [u32; 8] = [
0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
];
pub fn sha256_block_no_padding<E, CS>(
mut cs: CS,
input: &[Boolean]
) -> Result<Vec<Boolean>, SynthesisError>
where E: Engine, CS: ConstraintSystem<E>
{
assert_eq!(input.len(), 512);
Ok(sha256_compression_function(
&mut cs,
&input,
&get_sha256_iv()
)?
.into_iter()
.flat_map(|e| e.into_bits_be())
.collect())
}
pub fn sha256<E, CS>(
mut cs: CS,
input: &[Boolean]
) -> Result<Vec<Boolean>, SynthesisError>
where E: Engine, CS: ConstraintSystem<E>
{
assert!(input.len() % 8 == 0);
let mut padded = input.to_vec();
let plen = padded.len() as u64;
// append a single '1' bit
padded.push(Boolean::constant(true));
// append K '0' bits, where K is the minimum number >= 0 such that L + 1 + K + 64 is a multiple of 512
while (padded.len() + 64) % 512 != 0 {
padded.push(Boolean::constant(false));
}
// append L as a 64-bit big-endian integer, making the total post-processed length a multiple of 512 bits
for b in (0..64).rev().map(|i| (plen >> i) & 1 == 1) {
padded.push(Boolean::constant(b));
}
assert!(padded.len() % 512 == 0);
let mut cur = get_sha256_iv();
for (i, block) in padded.chunks(512).enumerate() {
cur = sha256_compression_function(
cs.namespace(|| format!("block {}", i)),
block,
&cur
)?;
}
Ok(cur.into_iter()
.flat_map(|e| e.into_bits_be())
.collect())
}
fn get_sha256_iv() -> Vec<UInt32> {
IV.iter().map(|&v| UInt32::constant(v)).collect()
}
fn sha256_compression_function<E, CS>(
cs: CS,
input: &[Boolean],
current_hash_value: &[UInt32]
) -> Result<Vec<UInt32>, SynthesisError>
where E: Engine, CS: ConstraintSystem<E>
{
assert_eq!(input.len(), 512);
assert_eq!(current_hash_value.len(), 8);
let mut w = input.chunks(32)
.map(|e| UInt32::from_bits_be(e))
.collect::<Vec<_>>();
// We can save some constraints by combining some of
// the constraints in different u32 additions
let mut cs = MultiEq::new(cs);
for i in 16..64 {
let cs = &mut cs.namespace(|| format!("w extension {}", i));
// s0 := (w[i-15] rightrotate 7) xor (w[i-15] rightrotate 18) xor (w[i-15] rightshift 3)
let mut s0 = w[i-15].rotr(7);
s0 = s0.xor(
cs.namespace(|| "first xor for s0"),
&w[i-15].rotr(18)
)?;
s0 = s0.xor(
cs.namespace(|| "second xor for s0"),
&w[i-15].shr(3)
)?;
// s1 := (w[i-2] rightrotate 17) xor (w[i-2] rightrotate 19) xor (w[i-2] rightshift 10)
let mut s1 = w[i-2].rotr(17);
s1 = s1.xor(
cs.namespace(|| "first xor for s1"),
&w[i-2].rotr(19)
)?;
s1 = s1.xor(
cs.namespace(|| "second xor for s1"),
&w[i-2].shr(10)
)?;
let tmp = UInt32::addmany(
cs.namespace(|| "computation of w[i]"),
&[w[i-16].clone(), s0, w[i-7].clone(), s1]
)?;
// w[i] := w[i-16] + s0 + w[i-7] + s1
w.push(tmp);
}
assert_eq!(w.len(), 64);
enum Maybe {
Deferred(Vec<UInt32>),
Concrete(UInt32)
}
impl Maybe {
fn compute<E, CS, M>(
self,
cs: M,
others: &[UInt32]
) -> Result<UInt32, SynthesisError>
where E: Engine,
CS: ConstraintSystem<E>,
M: ConstraintSystem<E, Root=MultiEq<E, CS>>
{
Ok(match self {
Maybe::Concrete(ref v) => {
return Ok(v.clone())
},
Maybe::Deferred(mut v) => {
v.extend(others.into_iter().cloned());
UInt32::addmany(
cs,
&v
)?
}
})
}
}
let mut a = Maybe::Concrete(current_hash_value[0].clone());
let mut b = current_hash_value[1].clone();
let mut c = current_hash_value[2].clone();
let mut d = current_hash_value[3].clone();
let mut e = Maybe::Concrete(current_hash_value[4].clone());
let mut f = current_hash_value[5].clone();
let mut g = current_hash_value[6].clone();
let mut h = current_hash_value[7].clone();
for i in 0..64 {
let cs = &mut cs.namespace(|| format!("compression round {}", i));
// S1 := (e rightrotate 6) xor (e rightrotate 11) xor (e rightrotate 25)
let new_e = e.compute(cs.namespace(|| "deferred e computation"), &[])?;
let mut s1 = new_e.rotr(6);
s1 = s1.xor(
cs.namespace(|| "first xor for s1"),
&new_e.rotr(11)
)?;
s1 = s1.xor(
cs.namespace(|| "second xor for s1"),
&new_e.rotr(25)
)?;
// ch := (e and f) xor ((not e) and g)
let ch = UInt32::sha256_ch(
cs.namespace(|| "ch"),
&new_e,
&f,
&g
)?;
// temp1 := h + S1 + ch + k[i] + w[i]
let temp1 = vec![
h.clone(),
s1,
ch,
UInt32::constant(ROUND_CONSTANTS[i]),
w[i].clone()
];
// S0 := (a rightrotate 2) xor (a rightrotate 13) xor (a rightrotate 22)
let new_a = a.compute(cs.namespace(|| "deferred a computation"), &[])?;
let mut s0 = new_a.rotr(2);
s0 = s0.xor(
cs.namespace(|| "first xor for s0"),
&new_a.rotr(13)
)?;
s0 = s0.xor(
cs.namespace(|| "second xor for s0"),
&new_a.rotr(22)
)?;
// maj := (a and b) xor (a and c) xor (b and c)
let maj = UInt32::sha256_maj(
cs.namespace(|| "maj"),
&new_a,
&b,
&c
)?;
// temp2 := S0 + maj
let temp2 = vec![s0, maj];
/*
h := g
g := f
f := e
e := d + temp1
d := c
c := b
b := a
a := temp1 + temp2
*/
h = g;
g = f;
f = new_e;
e = Maybe::Deferred(temp1.iter().cloned().chain(Some(d)).collect::<Vec<_>>());
d = c;
c = b;
b = new_a;
a = Maybe::Deferred(temp1.iter().cloned().chain(temp2.iter().cloned()).collect::<Vec<_>>());
}
/*
Add the compressed chunk to the current hash value:
h0 := h0 + a
h1 := h1 + b
h2 := h2 + c
h3 := h3 + d
h4 := h4 + e
h5 := h5 + f
h6 := h6 + g
h7 := h7 + h
*/
let h0 = a.compute(
cs.namespace(|| "deferred h0 computation"),
&[current_hash_value[0].clone()]
)?;
let h1 = UInt32::addmany(
cs.namespace(|| "new h1"),
&[current_hash_value[1].clone(), b]
)?;
let h2 = UInt32::addmany(
cs.namespace(|| "new h2"),
&[current_hash_value[2].clone(), c]
)?;
let h3 = UInt32::addmany(
cs.namespace(|| "new h3"),
&[current_hash_value[3].clone(), d]
)?;
let h4 = e.compute(
cs.namespace(|| "deferred h4 computation"),
&[current_hash_value[4].clone()]
)?;
let h5 = UInt32::addmany(
cs.namespace(|| "new h5"),
&[current_hash_value[5].clone(), f]
)?;
let h6 = UInt32::addmany(
cs.namespace(|| "new h6"),
&[current_hash_value[6].clone(), g]
)?;
let h7 = UInt32::addmany(
cs.namespace(|| "new h7"),
&[current_hash_value[7].clone(), h]
)?;
Ok(vec![h0, h1, h2, h3, h4, h5, h6, h7])
}
#[cfg(test)]
mod test {
use super::*;
use circuit::boolean::AllocatedBit;
use pairing::bls12_381::Bls12;
use circuit::test::TestConstraintSystem;
use rand::{XorShiftRng, SeedableRng, Rng};
#[test]
fn test_blank_hash() {
let iv = get_sha256_iv();
let mut cs = TestConstraintSystem::<Bls12>::new();
let mut input_bits: Vec<_> = (0..512).map(|_| Boolean::Constant(false)).collect();
input_bits[0] = Boolean::Constant(true);
let out = sha256_compression_function(
&mut cs,
&input_bits,
&iv
).unwrap();
let out_bits: Vec<_> = out.into_iter().flat_map(|e| e.into_bits_be()).collect();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 0);
let expected = hex!("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
let mut out = out_bits.into_iter();
for b in expected.into_iter() {
for i in (0..8).rev() {
let c = out.next().unwrap().get_value().unwrap();
assert_eq!(c, (b >> i) & 1u8 == 1u8);
}
}
}
#[test]
fn test_full_block() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let iv = get_sha256_iv();
let mut cs = TestConstraintSystem::<Bls12>::new();
let input_bits: Vec<_> = (0..512).map(|i| {
Boolean::from(
AllocatedBit::alloc(
cs.namespace(|| format!("input bit {}", i)),
Some(rng.gen())
).unwrap()
)
}).collect();
sha256_compression_function(
cs.namespace(|| "sha256"),
&input_bits,
&iv
).unwrap();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints() - 512, 25840);
}
#[test]
fn test_against_vectors() {
use crypto::sha2::Sha256;
use crypto::digest::Digest;
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for input_len in (0..32).chain((32..256).filter(|a| a % 8 == 0))
{
let mut h = Sha256::new();
let data: Vec<u8> = (0..input_len).map(|_| rng.gen()).collect();
h.input(&data);
let mut hash_result = [0u8; 32];
h.result(&mut hash_result[..]);
let mut cs = TestConstraintSystem::<Bls12>::new();
let mut input_bits = vec![];
for (byte_i, input_byte) in data.into_iter().enumerate() {
for bit_i in (0..8).rev() {
let cs = cs.namespace(|| format!("input bit {} {}", byte_i, bit_i));
input_bits.push(AllocatedBit::alloc(cs, Some((input_byte >> bit_i) & 1u8 == 1u8)).unwrap().into());
}
}
let r = sha256(&mut cs, &input_bits).unwrap();
assert!(cs.is_satisfied());
let mut s = hash_result.as_ref().iter()
.flat_map(|&byte| (0..8).rev().map(move |i| (byte >> i) & 1u8 == 1u8));
for b in r {
match b {
Boolean::Is(b) => {
assert!(s.next().unwrap() == b.get_value().unwrap());
},
Boolean::Not(b) => {
assert!(s.next().unwrap() != b.get_value().unwrap());
},
Boolean::Constant(b) => {
assert!(input_len == 0);
assert!(s.next().unwrap() == b);
}
}
}
}
}
}

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@ -9,6 +9,9 @@ extern crate byteorder;
#[macro_use]
extern crate hex_literal;
#[cfg(test)]
extern crate crypto;
pub mod jubjub;
pub mod group_hash;
pub mod circuit;