40 lines
1.3 KiB
Rust
40 lines
1.3 KiB
Rust
use blake2_rfc::blake2b::Blake2b;
|
|
|
|
use jubjub::{JubjubEngine, ToUniform};
|
|
|
|
pub fn swap_bits_u64(x: u64) -> u64
|
|
{
|
|
let mut tmp = 0;
|
|
for i in 0..64 {
|
|
tmp |= ((x >> i) & 1) << (63 - i);
|
|
}
|
|
tmp
|
|
}
|
|
|
|
pub fn hash_to_scalar<E: JubjubEngine>(persona: &[u8], a: &[u8], b: &[u8]) -> E::Fs {
|
|
let mut hasher = Blake2b::with_params(64, &[], &[], persona);
|
|
hasher.update(a);
|
|
hasher.update(b);
|
|
let ret = hasher.finalize();
|
|
E::Fs::to_uniform(ret.as_ref())
|
|
}
|
|
|
|
#[test]
|
|
fn test_swap_bits_u64() {
|
|
assert_eq!(swap_bits_u64(17182120934178543809), 0b1000001100011011110000011000111000101111111001001100111001110111);
|
|
assert_eq!(swap_bits_u64(15135675916470734665), 0b1001001011110010001101010010001110110000100111010011000001001011);
|
|
assert_eq!(swap_bits_u64(6724233301461108393), 0b1001010101100000100011100001010111110001011000101000101010111010);
|
|
assert_eq!(swap_bits_u64(206708183275952289), 0b1000010100011010001010100011101011111111111110100111101101000000);
|
|
assert_eq!(swap_bits_u64(12712751566144824320), 0b0000000000100110010110111000001110001100001000110011011000001101);
|
|
|
|
let mut a = 15863238721320035327u64;
|
|
for _ in 0..1000 {
|
|
a = a.wrapping_mul(a);
|
|
|
|
let swapped = swap_bits_u64(a);
|
|
let unswapped = swap_bits_u64(swapped);
|
|
|
|
assert_eq!(a, unswapped);
|
|
}
|
|
}
|