sha.rs

1const ROUND: [u32; 64] = [2    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,3    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,4    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,5    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,6    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,7    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,8    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,9    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,10];1112const START: [u32; 8] = [13    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,14];1516fn block(state: &mut [u32; 8], chunk: &[u8]) {17    let mut w = [0u32; 64];18    for (i, word) in chunk.chunks(4).enumerate() {19        w[i] = u32::from_be_bytes([word[0], word[1], word[2], word[3]]);20    }21    for i in 16..64 {22        let s0 = w[i - 15].rotate_right(7) ^ w[i - 15].rotate_right(18) ^ (w[i - 15] >> 3);23        let s1 = w[i - 2].rotate_right(17) ^ w[i - 2].rotate_right(19) ^ (w[i - 2] >> 10);24        w[i] = w[i - 16]25            .wrapping_add(s0)26            .wrapping_add(w[i - 7])27            .wrapping_add(s1);28    }29    let [mut a, mut b, mut c, mut d, mut e, mut f, mut g, mut h] = *state;30    for i in 0..64 {31        let s1 = e.rotate_right(6) ^ e.rotate_right(11) ^ e.rotate_right(25);32        let choice = (e & f) ^ (!e & g);33        let t1 = h34            .wrapping_add(s1)35            .wrapping_add(choice)36            .wrapping_add(ROUND[i])37            .wrapping_add(w[i]);38        let s0 = a.rotate_right(2) ^ a.rotate_right(13) ^ a.rotate_right(22);39        let majority = (a & b) ^ (a & c) ^ (b & c);40        let t2 = s0.wrapping_add(majority);41        h = g;42        g = f;43        f = e;44        e = d.wrapping_add(t1);45        d = c;46        c = b;47        b = a;48        a = t1.wrapping_add(t2);49    }50    for (slot, add) in state.iter_mut().zip([a, b, c, d, e, f, g, h]) {51        *slot = slot.wrapping_add(add);52    }53}5455pub(crate) fn sha256(bytes: &[u8]) -> [u8; 32] {56    let mut padded = bytes.to_vec();57    padded.push(0x80);58    while padded.len() % 64 != 56 {59        padded.push(0);60    }61    padded.extend_from_slice(&((bytes.len() as u64) * 8).to_be_bytes());62    let mut state = START;63    for chunk in padded.chunks(64) {64        block(&mut state, chunk);65    }66    let mut out = [0u8; 32];67    for (i, word) in state.iter().enumerate() {68        out[i * 4..i * 4 + 4].copy_from_slice(&word.to_be_bytes());69    }70    out71}7273pub(crate) fn short(bytes: &[u8]) -> String {74    sha256(bytes)[..4]75        .iter()76        .map(|b| format!("{b:02x}"))77        .collect()78}7980#[cfg(test)]81mod tests {82    use super::*;8384    fn hex(bytes: &[u8]) -> String {85        bytes.iter().map(|b| format!("{b:02x}")).collect()86    }8788    #[test]89    fn the_standard_vectors_hold() {90        assert_eq!(91            hex(&sha256(b"")),92            "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"93        );94        assert_eq!(95            hex(&sha256(b"abc")),96            "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"97        );98        assert_eq!(99            hex(&sha256(100                b"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"101            )),102            "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1"103        );104        assert_eq!(short(b"abc"), "ba7816bf");105    }106}