1use std::io::{self, Read};
6
7const K: [u32; 64] = [
8 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74,
9 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d,
10 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e,
11 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
12 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
13];
14
15#[derive(Clone)]
16pub struct Sha256 {
17 h: [u32; 8],
18 block: [u8; 64],
19 used: usize,
20 length: u64,
21}
22
23impl Default for Sha256 {
24 fn default() -> Self {
25 Self { h: [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19], block: [0; 64], used: 0, length: 0 }
26 }
27}
28
29impl Sha256 {
30 pub fn update(&mut self, mut data: &[u8]) {
31 self.length = self.length.wrapping_add(data.len() as u64);
32 while !data.is_empty() {
33 let take = (64 - self.used).min(data.len());
34 self.block[self.used..self.used + take].copy_from_slice(&data[..take]);
35 self.used += take;
36 data = &data[take..];
37 if self.used == 64 {
38 compress(&mut self.h, &self.block);
39 self.used = 0;
40 }
41 }
42 }
43
44 pub fn finish(mut self) -> [u8; 32] {
45 let bits = self.length.wrapping_mul(8);
46 self.update(&[0x80]);
47 while self.used != 56 {
48 self.update(&[0]);
49 }
50 self.update(&bits.to_be_bytes());
51 let mut out = [0u8; 32];
52 for (bytes, word) in out.as_chunks_mut::<4>().0.iter_mut().zip(self.h) {
53 *bytes = word.to_be_bytes();
54 }
55 out
56 }
57}
58
59fn compress(h: &mut [u32; 8], block: &[u8; 64]) {
60 let mut w = [0u32; 64];
61 for (i, word) in block.as_chunks::<4>().0.iter().enumerate() {
62 w[i] = u32::from_be_bytes(*word);
63 }
64 for i in 16..64 {
65 let s0 = w[i - 15].rotate_right(7) ^ w[i - 15].rotate_right(18) ^ (w[i - 15] >> 3);
66 let s1 = w[i - 2].rotate_right(17) ^ w[i - 2].rotate_right(19) ^ (w[i - 2] >> 10);
67 w[i] = w[i - 16].wrapping_add(s0).wrapping_add(w[i - 7]).wrapping_add(s1);
68 }
69 let [mut a, mut b, mut c, mut d, mut e, mut f, mut g, mut hh] = *h;
70 for i in 0..64 {
71 let s1 = e.rotate_right(6) ^ e.rotate_right(11) ^ e.rotate_right(25);
72 let ch = (e & f) ^ (!e & g);
73 let t1 = hh.wrapping_add(s1).wrapping_add(ch).wrapping_add(K[i]).wrapping_add(w[i]);
74 let s0 = a.rotate_right(2) ^ a.rotate_right(13) ^ a.rotate_right(22);
75 let maj = (a & b) ^ (a & c) ^ (b & c);
76 (hh, g, f, e, d, c, b, a) = (g, f, e, d.wrapping_add(t1), c, b, a, t1.wrapping_add(s0.wrapping_add(maj)));
77 }
78 for (x, y) in h.iter_mut().zip([a, b, c, d, e, f, g, hh]) {
79 *x = x.wrapping_add(y);
80 }
81}
82
83pub fn sha256(data: &[u8]) -> [u8; 32] {
84 let mut s = Sha256::default();
85 s.update(data);
86 s.finish()
87}
88
89pub fn sha256_reader(mut reader: impl Read) -> io::Result<([u8; 32], u64)> {
91 let mut s = Sha256::default();
92 let mut buf = vec![0u8; 1 << 16];
93 let mut total = 0u64;
94 loop {
95 match reader.read(&mut buf) {
96 Ok(0) => return Ok((s.finish(), total)),
97 Ok(n) => {
98 s.update(&buf[..n]);
99 total += n as u64;
100 }
101 Err(e) if e.kind() == io::ErrorKind::Interrupted => {}
102 Err(e) => return Err(e),
103 }
104 }
105}
106
107pub fn hmac(key: &[u8], message: &[u8]) -> [u8; 32] {
108 let mut block = [0u8; 64];
109 if key.len() > 64 {
110 block[..32].copy_from_slice(&sha256(key));
111 } else {
112 block[..key.len()].copy_from_slice(key);
113 }
114 let mut inner = Sha256::default();
115 inner.update(&block.map(|b| b ^ 0x36));
116 inner.update(message);
117 let mut outer = Sha256::default();
118 outer.update(&block.map(|b| b ^ 0x5c));
119 outer.update(&inner.finish());
120 outer.finish()
121}
122
123pub fn hex(bytes: &[u8]) -> String {
124 const DIGITS: &[u8; 16] = b"0123456789abcdef";
125 let mut s = String::with_capacity(bytes.len() * 2);
126 for b in bytes {
127 s.push(DIGITS[usize::from(b >> 4)] as char);
128 s.push(DIGITS[usize::from(b & 15)] as char);
129 }
130 s
131}
132
133#[cfg(test)]
134mod tests {
135 use super::*;
136
137 #[test]
138 fn fips_180_vectors() {
139 assert_eq!(hex(&sha256(b"")), "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
140 assert_eq!(hex(&sha256(b"abc")), "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad");
141 assert_eq!(hex(&sha256(b"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq")), "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1");
142 }
143
144 #[test]
145 fn a_stream_in_pieces_hashes_as_the_whole() {
146 let data: Vec<u8> = (0..10_000u32).map(|i| (i * 7 % 251) as u8).collect();
147 let mut s = Sha256::default();
148 for piece in data.chunks(97) {
149 s.update(piece);
150 }
151 assert_eq!(s.finish(), sha256(&data));
152 assert_eq!(sha256_reader(&data[..]).unwrap(), (sha256(&data), 10_000));
153 }
154
155 #[test]
156 fn rfc_4231_hmac() {
157 assert_eq!(hex(&hmac(&[0x0b; 20], b"Hi There")), "b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7");
158 assert_eq!(hex(&hmac(b"Jefe", b"what do ya want for nothing?")), "5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843");
159 assert_eq!(hex(&hmac(&[0xaa; 131], b"Test Using Larger Than Block-Size Key - Hash Key First")), "60e431591ee0b67f0d8a26aacbf5b77f8e0bc6213728c5140546040f0ee37f54");
160 }
161}