zenith_float_num/
hash.rs

1//! SHA-2, HMAC-SHA-256, and constant-time byte compare. Integer only.
2
3/// SHA-256 of `data`.
4pub fn sha256(data: &[u8]) -> [u8; 32] {
5    let mut h = SHA256_IV;
6    let (n_full, tail) = padded_blocks::<64>(data, 8);
7    for i in 0..n_full {
8        sha256_compress(&mut h, &block64(data, i));
9    }
10    for blk in &tail {
11        sha256_compress(&mut h, blk);
12    }
13    let mut out = [0u8; 32];
14    for (i, w) in h.iter().enumerate() {
15        out[i * 4..(i + 1) * 4].copy_from_slice(&w.to_be_bytes());
16    }
17    out
18}
19
20/// SHA-512 of `data`.
21pub fn sha512(data: &[u8]) -> [u8; 64] {
22    let mut h = SHA512_IV;
23    let (n_full, tail) = padded_blocks::<128>(data, 16);
24    for i in 0..n_full {
25        sha512_compress(&mut h, &block128(data, i));
26    }
27    for blk in &tail {
28        sha512_compress(&mut h, blk);
29    }
30    let mut out = [0u8; 64];
31    for (i, w) in h.iter().enumerate() {
32        out[i * 8..(i + 1) * 8].copy_from_slice(&w.to_be_bytes());
33    }
34    out
35}
36
37/// HMAC-SHA-256 (`key`, `data`).
38pub fn hmac_sha256(key: &[u8], data: &[u8]) -> [u8; 32] {
39    let mut k = [0u8; 64];
40    if key.len() > 64 {
41        k[..32].copy_from_slice(&sha256(key));
42    } else {
43        k[..key.len()].copy_from_slice(key);
44    }
45    let mut ipad = [0x36u8; 64];
46    let mut opad = [0x5cu8; 64];
47    for i in 0..64 {
48        ipad[i] ^= k[i];
49        opad[i] ^= k[i];
50    }
51    let mut inner = alloc::vec![0u8; 64 + data.len()];
52    inner[..64].copy_from_slice(&ipad);
53    inner[64..].copy_from_slice(data);
54    let ih = sha256(&inner);
55    let mut outer = [0u8; 96];
56    outer[..64].copy_from_slice(&opad);
57    outer[64..].copy_from_slice(&ih);
58    sha256(&outer)
59}
60
61/// Timing-safe equality: always scans both slices; length mismatch is `false`.
62pub fn constant_time_eq(a: &[u8], b: &[u8]) -> bool {
63    let mut diff = (a.len() ^ b.len()) as u8;
64    let n = a.len().min(b.len());
65    for i in 0..n {
66        diff |= a[i] ^ b[i];
67    }
68    if a.len() != b.len() {
69        for &x in &a[n..] {
70            diff |= x;
71        }
72        for &x in &b[n..] {
73            diff |= x;
74        }
75    }
76    diff == 0
77}
78
79fn block64(data: &[u8], i: usize) -> [u8; 64] {
80    let mut b = [0u8; 64];
81    b.copy_from_slice(&data[i * 64..(i + 1) * 64]);
82    b
83}
84
85fn block128(data: &[u8], i: usize) -> [u8; 128] {
86    let mut b = [0u8; 128];
87    b.copy_from_slice(&data[i * 128..(i + 1) * 128]);
88    b
89}
90
91/// Full unpadded blocks, then one or two padded tail blocks.
92fn padded_blocks<const B: usize>(
93    data: &[u8],
94    len_bytes: usize,
95) -> (usize, alloc::vec::Vec<[u8; B]>) {
96    let n_full = data.len() / B;
97    let rem = data.len() % B;
98    let bit_len = (data.len() as u128).wrapping_mul(8);
99    let mut tail = alloc::vec::Vec::new();
100    let mut blk = [0u8; B];
101    blk[..rem].copy_from_slice(&data[n_full * B..]);
102    blk[rem] = 0x80;
103    let need = rem + 1 + len_bytes;
104    if need > B {
105        tail.push(blk);
106        blk = [0u8; B];
107    }
108    write_be_len(&mut blk[B - len_bytes..], bit_len, len_bytes);
109    tail.push(blk);
110    (n_full, tail)
111}
112
113fn write_be_len(dst: &mut [u8], bit_len: u128, len_bytes: usize) {
114    if len_bytes == 8 {
115        dst.copy_from_slice(&(bit_len as u64).to_be_bytes());
116    } else {
117        dst.copy_from_slice(&bit_len.to_be_bytes());
118    }
119}
120
121fn rotr32(x: u32, n: u32) -> u32 {
122    x.rotate_right(n)
123}
124
125fn rotr64(x: u64, n: u32) -> u64 {
126    x.rotate_right(n)
127}
128
129fn sha256_compress(h: &mut [u32; 8], block: &[u8; 64]) {
130    let mut w = [0u32; 64];
131    for i in 0..16 {
132        w[i] = u32::from_be_bytes([
133            block[i * 4],
134            block[i * 4 + 1],
135            block[i * 4 + 2],
136            block[i * 4 + 3],
137        ]);
138    }
139    for i in 16..64 {
140        let s0 = rotr32(w[i - 15], 7) ^ rotr32(w[i - 15], 18) ^ (w[i - 15] >> 3);
141        let s1 = rotr32(w[i - 2], 17) ^ rotr32(w[i - 2], 19) ^ (w[i - 2] >> 10);
142        w[i] = w[i - 16]
143            .wrapping_add(s0)
144            .wrapping_add(w[i - 7])
145            .wrapping_add(s1);
146    }
147    let mut a = h[0];
148    let mut b = h[1];
149    let mut c = h[2];
150    let mut d = h[3];
151    let mut e = h[4];
152    let mut f = h[5];
153    let mut g = h[6];
154    let mut hh = h[7];
155    for i in 0..64 {
156        let s1 = rotr32(e, 6) ^ rotr32(e, 11) ^ rotr32(e, 25);
157        let ch = (e & f) ^ ((!e) & g);
158        let t1 = hh
159            .wrapping_add(s1)
160            .wrapping_add(ch)
161            .wrapping_add(SHA256_K[i])
162            .wrapping_add(w[i]);
163        let s0 = rotr32(a, 2) ^ rotr32(a, 13) ^ rotr32(a, 22);
164        let maj = (a & b) ^ (a & c) ^ (b & c);
165        let t2 = s0.wrapping_add(maj);
166        hh = g;
167        g = f;
168        f = e;
169        e = d.wrapping_add(t1);
170        d = c;
171        c = b;
172        b = a;
173        a = t1.wrapping_add(t2);
174    }
175    h[0] = h[0].wrapping_add(a);
176    h[1] = h[1].wrapping_add(b);
177    h[2] = h[2].wrapping_add(c);
178    h[3] = h[3].wrapping_add(d);
179    h[4] = h[4].wrapping_add(e);
180    h[5] = h[5].wrapping_add(f);
181    h[6] = h[6].wrapping_add(g);
182    h[7] = h[7].wrapping_add(hh);
183}
184
185fn sha512_compress(h: &mut [u64; 8], block: &[u8; 128]) {
186    let mut w = [0u64; 80];
187    for i in 0..16 {
188        w[i] = u64::from_be_bytes([
189            block[i * 8],
190            block[i * 8 + 1],
191            block[i * 8 + 2],
192            block[i * 8 + 3],
193            block[i * 8 + 4],
194            block[i * 8 + 5],
195            block[i * 8 + 6],
196            block[i * 8 + 7],
197        ]);
198    }
199    for i in 16..80 {
200        let s0 = rotr64(w[i - 15], 1) ^ rotr64(w[i - 15], 8) ^ (w[i - 15] >> 7);
201        let s1 = rotr64(w[i - 2], 19) ^ rotr64(w[i - 2], 61) ^ (w[i - 2] >> 6);
202        w[i] = w[i - 16]
203            .wrapping_add(s0)
204            .wrapping_add(w[i - 7])
205            .wrapping_add(s1);
206    }
207    let mut a = h[0];
208    let mut b = h[1];
209    let mut c = h[2];
210    let mut d = h[3];
211    let mut e = h[4];
212    let mut f = h[5];
213    let mut g = h[6];
214    let mut hh = h[7];
215    for i in 0..80 {
216        let s1 = rotr64(e, 14) ^ rotr64(e, 18) ^ rotr64(e, 41);
217        let ch = (e & f) ^ ((!e) & g);
218        let t1 = hh
219            .wrapping_add(s1)
220            .wrapping_add(ch)
221            .wrapping_add(SHA512_K[i])
222            .wrapping_add(w[i]);
223        let s0 = rotr64(a, 28) ^ rotr64(a, 34) ^ rotr64(a, 39);
224        let maj = (a & b) ^ (a & c) ^ (b & c);
225        let t2 = s0.wrapping_add(maj);
226        hh = g;
227        g = f;
228        f = e;
229        e = d.wrapping_add(t1);
230        d = c;
231        c = b;
232        b = a;
233        a = t1.wrapping_add(t2);
234    }
235    h[0] = h[0].wrapping_add(a);
236    h[1] = h[1].wrapping_add(b);
237    h[2] = h[2].wrapping_add(c);
238    h[3] = h[3].wrapping_add(d);
239    h[4] = h[4].wrapping_add(e);
240    h[5] = h[5].wrapping_add(f);
241    h[6] = h[6].wrapping_add(g);
242    h[7] = h[7].wrapping_add(hh);
243}
244
245const SHA256_IV: [u32; 8] = [
246    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
247];
248
249const SHA256_K: [u32; 64] = [
250    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
251    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
252    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
253    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
254    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
255    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
256    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
257    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
258];
259
260const SHA512_IV: [u64; 8] = [
261    0x6a09e667f3bcc908,
262    0xbb67ae8584caa73b,
263    0x3c6ef372fe94f82b,
264    0xa54ff53a5f1d36f1,
265    0x510e527fade682d1,
266    0x9b05688c2b3e6c1f,
267    0x1f83d9abfb41bd6b,
268    0x5be0cd19137e2179,
269];
270
271const SHA512_K: [u64; 80] = [
272    0x428a2f98d728ae22,
273    0x7137449123ef65cd,
274    0xb5c0fbcfec4d3b2f,
275    0xe9b5dba58189dbbc,
276    0x3956c25bf348b538,
277    0x59f111f1b605d019,
278    0x923f82a4af194f9b,
279    0xab1c5ed5da6d8118,
280    0xd807aa98a3030242,
281    0x12835b0145706fbe,
282    0x243185be4ee4b28c,
283    0x550c7dc3d5ffb4e2,
284    0x72be5d74f27b896f,
285    0x80deb1fe3b1696b1,
286    0x9bdc06a725c71235,
287    0xc19bf174cf692694,
288    0xe49b69c19ef14ad2,
289    0xefbe4786384f25e3,
290    0x0fc19dc68b8cd5b5,
291    0x240ca1cc77ac9c65,
292    0x2de92c6f592b0275,
293    0x4a7484aa6ea6e483,
294    0x5cb0a9dcbd41fbd4,
295    0x76f988da831153b5,
296    0x983e5152ee66dfab,
297    0xa831c66d2db43210,
298    0xb00327c898fb213f,
299    0xbf597fc7beef0ee4,
300    0xc6e00bf33da88fc2,
301    0xd5a79147930aa725,
302    0x06ca6351e003826f,
303    0x142929670a0e6e70,
304    0x27b70a8546d22ffc,
305    0x2e1b21385c26c926,
306    0x4d2c6dfc5ac42aed,
307    0x53380d139d95b3df,
308    0x650a73548baf63de,
309    0x766a0abb3c77b2a8,
310    0x81c2c92e47edaee6,
311    0x92722c851482353b,
312    0xa2bfe8a14cf10364,
313    0xa81a664bbc423001,
314    0xc24b8b70d0f89791,
315    0xc76c51a30654be30,
316    0xd192e819d6ef5218,
317    0xd69906245565a910,
318    0xf40e35855771202a,
319    0x106aa07032bbd1b8,
320    0x19a4c116b8d2d0c8,
321    0x1e376c085141ab53,
322    0x2748774cdf8eeb99,
323    0x34b0bcb5e19b48a8,
324    0x391c0cb3c5c95a63,
325    0x4ed8aa4ae3418acb,
326    0x5b9cca4f7763e373,
327    0x682e6ff3d6b2b8a3,
328    0x748f82ee5defb2fc,
329    0x78a5636f43172f60,
330    0x84c87814a1f0ab72,
331    0x8cc702081a6439ec,
332    0x90befffa23631e28,
333    0xa4506cebde82bde9,
334    0xbef9a3f7b2c67915,
335    0xc67178f2e372532b,
336    0xca273eceea26619c,
337    0xd186b8c721c0c207,
338    0xeada7dd6cde0eb1e,
339    0xf57d4f7fee6ed178,
340    0x06f067aa72176fba,
341    0x0a637dc5a2c898a6,
342    0x113f9804bef90dae,
343    0x1b710b35131c471b,
344    0x28db77f523047d84,
345    0x32caab7b40c72493,
346    0x3c9ebe0a15c9bebc,
347    0x431d67c49c100d4c,
348    0x4cc5d4becb3e42b6,
349    0x597f299cfc657e2a,
350    0x5fcb6fab3ad6faec,
351    0x6c44198c4a475817,
352];
353
354#[cfg(test)]
355mod tests {
356    use super::*;
357
358    fn hex32(s: &str) -> [u8; 32] {
359        let mut o = [0u8; 32];
360        for i in 0..32 {
361            o[i] = u8::from_str_radix(&s[i * 2..i * 2 + 2], 16).unwrap();
362        }
363        o
364    }
365
366    #[test]
367    fn hash_sha256_hmac_ct() {
368        assert_eq!(
369            sha256(b""),
370            hex32("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
371        );
372        assert_eq!(
373            sha256(b"abc"),
374            hex32("ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad")
375        );
376        let mut key = [0u8; 20];
377        key.fill(0x0b);
378        assert_eq!(
379            hmac_sha256(&key, b"Hi There"),
380            hex32("b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7")
381        );
382        assert!(constant_time_eq(b"abc", b"abc"));
383        assert!(!constant_time_eq(b"abc", b"abx"));
384        assert_eq!(
385            constant_time_eq(&[0, 1, 0], &[1, 0, 0]),
386            constant_time_eq(&[0, 0, 1], &[0, 1, 0])
387        );
388        assert!(!constant_time_eq(&[0, 1, 0], &[1, 0, 0]));
389        assert!(!constant_time_eq(b"ab", b"abc"));
390        assert_eq!(
391            sha512(b""),
392            [
393                0xcf, 0x83, 0xe1, 0x35, 0x7e, 0xef, 0xb8, 0xbd, 0xf1, 0x54, 0x28, 0x50, 0xd6, 0x6d,
394                0x80, 0x07, 0xd6, 0x20, 0xe4, 0x05, 0x0b, 0x57, 0x15, 0xdc, 0x83, 0xf4, 0xa9, 0x21,
395                0xd3, 0x6c, 0xe9, 0xce, 0x47, 0xd0, 0xd1, 0x3c, 0x5d, 0x85, 0xf2, 0xb0, 0xff, 0x83,
396                0x18, 0xd2, 0x87, 0x7e, 0xec, 0x2f, 0x63, 0xb9, 0x31, 0xbd, 0x47, 0x41, 0x7a, 0x81,
397                0xa5, 0x38, 0x32, 0x7a, 0xf9, 0x27, 0xda, 0x3e,
398            ]
399        );
400    }
401}
zenith_float_num/hash.rs

zenith_float_num/
hash.rs
