1 files changed, 151 insertions, 0 deletions
diff --git a/kit/sha256.c b/kit/sha256.c
new file mode 100644
index 0000000..3abe972
--- /dev/null
+++ b/kit/sha256.c
@@ -0,0 +1,151 @@
+#include "sha256.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define ROTLEFT(a, b) (((a) << (b)) | ((a) >> (32 - (b))))
+#define ROTRIGHT(a, b) (((a) >> (b)) | ((a) << (32 - (b))))
+
+#define CH(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
+#define MAJ(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+#define EP0(x) (ROTRIGHT(x, 2) ^ ROTRIGHT(x, 13) ^ ROTRIGHT(x, 22))
+#define EP1(x) (ROTRIGHT(x, 6) ^ ROTRIGHT(x, 11) ^ ROTRIGHT(x, 25))
+#define SIG0(x) (ROTRIGHT(x, 7) ^ ROTRIGHT(x, 18) ^ ((x) >> 3))
+#define SIG1(x) (ROTRIGHT(x, 17) ^ ROTRIGHT(x, 19) ^ ((x) >> 10))
+
+static u32 kit_sha256_k[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
+};
+
+static void kit_sha256_transform(u32 *state, u8 *data) {
+  assert(state != NULL);
+  assert(data != NULL);
+
+  u32 a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];
+
+  for (i = 0, j = 0; i < 16; ++i, j += 4)
+    m[i] = ((u32) data[j] << 24) | ((u32) data[j + 1] << 16) |
+           ((u32) data[j + 2] << 8) | ((u32) data[j + 3]);
+  for (; i < 64; ++i)
+    m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16];
+
+  a = state[0];
+  b = state[1];
+  c = state[2];
+  d = state[3];
+  e = state[4];
+  f = state[5];
+  g = state[6];
+  h = state[7];
+
+  for (i = 0; i < 64; ++i) {
+    t1 = h + EP1(e) + CH(e, f, g) + kit_sha256_k[i] + m[i];
+    t2 = EP0(a) + MAJ(a, b, c);
+    h  = g;
+    g  = f;
+    f  = e;
+    e  = d + t1;
+    d  = c;
+    c  = b;
+    b  = a;
+    a  = t1 + t2;
+  }
+
+  state[0] += a;
+  state[1] += b;
+  state[2] += c;
+  state[3] += d;
+  state[4] += e;
+  state[5] += f;
+  state[6] += g;
+  state[7] += h;
+}
+
+kit_sha256_hash_t kit_sha256(i64 in_size, u8 *in_data) {
+  assert(in_size >= 0);
+  assert(in_data != NULL);
+
+  u32 state[8] = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
+                   0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 };
+
+  u8 data[64];
+
+  i64 i;
+  i64 datalen = 0;
+  u64 bitlen  = 0;
+
+  if (in_data != NULL)
+    for (i = 0; i < in_size; ++i) {
+      data[datalen] = in_data[i];
+      datalen++;
+
+      if (datalen != 64)
+        continue;
+
+      kit_sha256_transform(state, data);
+      bitlen += 512;
+      datalen = 0;
+    }
+
+  i = datalen;
+
+  if (datalen < 56) {
+    data[i++] = 0x80;
+    while (i < 56) data[i++] = 0x00;
+  } else {
+    data[i++] = 0x80;
+    while (i < 64) data[i++] = 0x00;
+
+    kit_sha256_transform(state, data);
+    memset(data, 0, 56);
+  }
+
+  bitlen += datalen * 8;
+  data[63] = bitlen;
+  data[62] = bitlen >> 8;
+  data[61] = bitlen >> 16;
+  data[60] = bitlen >> 24;
+  data[59] = bitlen >> 32;
+  data[58] = bitlen >> 40;
+  data[57] = bitlen >> 48;
+  data[56] = bitlen >> 56;
+
+  kit_sha256_transform(state, data);
+
+  kit_sha256_hash_t hash;
+  memset(&hash, 0, sizeof hash);
+
+  for (i = 0; i < 4; ++i) {
+    hash.v[i]      = (state[0] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 4]  = (state[1] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 8]  = (state[2] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 12] = (state[3] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 16] = (state[4] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 20] = (state[5] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 24] = (state[6] >> (24 - i * 8)) & 0xff;
+    hash.v[i + 28] = (state[7] >> (24 - i * 8)) & 0xff;
+  }
+
+  return hash;
+}
+
+#undef ROTLEFT
+#undef ROTRIGHT
+#undef CH
+#undef MAJ
+#undef EP0
+#undef EP1
+#undef SIG0
+#undef SIG1