blake2b.cpp

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// taken from here
// https://github.com/mjosaarinen/blake2_mjosref/blob/master/blake2b.c

// blake2b.c
// A simple BLAKE2b Reference Implementation.

#include "blake2b.h"

namespace kagome::crypto {

  // Cyclic right rotation.

#ifndef ROTR64
#define ROTR64(x, y) (((x) >> (y)) ^ ((x) << (64 - (y))))
#endif

  // Little-endian byte access.

#define B2B_GET64(p)                                                        \
  (((uint64_t)((uint8_t *)(p))[0]) ^ (((uint64_t)((uint8_t *)(p))[1]) << 8) \
   ^ (((uint64_t)((uint8_t *)(p))[2]) << 16)                                \
   ^ (((uint64_t)((uint8_t *)(p))[3]) << 24)                                \
   ^ (((uint64_t)((uint8_t *)(p))[4]) << 32)                                \
   ^ (((uint64_t)((uint8_t *)(p))[5]) << 40)                                \
   ^ (((uint64_t)((uint8_t *)(p))[6]) << 48)                                \
   ^ (((uint64_t)((uint8_t *)(p))[7]) << 56))

  // G Mixing function.

#define B2B_G(a, b, c, d, x, y)     \
  {                                 \
    v[a] = v[a] + v[b] + (x);       \
    v[d] = ROTR64(v[d] ^ v[a], 32); \
    v[c] = v[c] + v[d];             \
    v[b] = ROTR64(v[b] ^ v[c], 24); \
    v[a] = v[a] + v[b] + (y);       \
    v[d] = ROTR64(v[d] ^ v[a], 16); \
    v[c] = v[c] + v[d];             \
    v[b] = ROTR64(v[b] ^ v[c], 63); \
  }

  // Initialization Vector.

  static const uint64_t blake2b_iv[8] = {0x6A09E667F3BCC908,
                                         0xBB67AE8584CAA73B,
                                         0x3C6EF372FE94F82B,
                                         0xA54FF53A5F1D36F1,
                                         0x510E527FADE682D1,
                                         0x9B05688C2B3E6C1F,
                                         0x1F83D9ABFB41BD6B,
                                         0x5BE0CD19137E2179};

  // Compression function. "last" flag indicates last block.

  static void blake2b_compress(blake2b_ctx *ctx, int last) {
    const uint8_t sigma[12][16] = {
        {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
        {14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3},
        {11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4},
        {7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8},
        {9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13},
        {2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9},
        {12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11},
        {13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10},
        {6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5},
        {10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0},
        {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
        {14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3}};
    int i;
    uint64_t v[16];
    uint64_t m[16];

    for (i = 0; i < 8; i++) {  // init work variables
      v[i] = ctx->h[i];
      v[i + 8] = blake2b_iv[i];
    }

    v[12] ^= ctx->t[0];  // low 64 bits of offset
    v[13] ^= ctx->t[1];  // high 64 bits
    if (last) {          // last block flag set ?
      v[14] = ~v[14];
    }

    for (i = 0; i < 16; i++) {  // get little-endian words
      m[i] = B2B_GET64(&ctx->b[8 * i]);
    }

    for (i = 0; i < 12; i++) {  // twelve rounds
      B2B_G(0, 4, 8, 12, m[sigma[i][0]], m[sigma[i][1]]);
      B2B_G(1, 5, 9, 13, m[sigma[i][2]], m[sigma[i][3]]);
      B2B_G(2, 6, 10, 14, m[sigma[i][4]], m[sigma[i][5]]);
      B2B_G(3, 7, 11, 15, m[sigma[i][6]], m[sigma[i][7]]);
      B2B_G(0, 5, 10, 15, m[sigma[i][8]], m[sigma[i][9]]);
      B2B_G(1, 6, 11, 12, m[sigma[i][10]], m[sigma[i][11]]);
      B2B_G(2, 7, 8, 13, m[sigma[i][12]], m[sigma[i][13]]);
      B2B_G(3, 4, 9, 14, m[sigma[i][14]], m[sigma[i][15]]);
    }

    for (i = 0; i < 8; ++i) {
      ctx->h[i] ^= v[i] ^ v[i + 8];
    }
  }

  // Initialize the hashing context "ctx" with optional key "key".
  //      1 <= outlen <= 64 gives the digest size in bytes.
  //      Secret key (also <= 64 bytes) is optional (keylen = 0).

  int blake2b_init(blake2b_ctx *ctx,
                   size_t outlen,
                   const void *key,
                   size_t keylen)  // (keylen=0: no key)
  {
    size_t i;

    if (outlen == 0 || outlen > 64 || keylen > 64) {
      return -1;  // illegal parameters
    }

    for (i = 0; i < 8; i++) {  // state, "param block"
      ctx->h[i] = blake2b_iv[i];
    }
    ctx->h[0] ^= 0x01010000 ^ (keylen << 8) ^ outlen;

    ctx->t[0] = 0;  // input count low word
    ctx->t[1] = 0;  // input count high word
    ctx->c = 0;     // pointer within buffer
    ctx->outlen = outlen;

    for (i = keylen; i < 128; i++) {  // zero input block
      ctx->b[i] = 0;
    }
    if (keylen > 0) {
      blake2b_update(ctx, key, keylen);
      ctx->c = 128;  // at the end
    }

    return 0;
  }

  // Add "inlen" bytes from "in" into the hash.

  void blake2b_update(blake2b_ctx *ctx,
                      const void *in,
                      size_t inlen)  // data bytes
  {
    size_t i;

    for (i = 0; i < inlen; i++) {
      if (ctx->c == 128) {         // buffer full ?
        ctx->t[0] += ctx->c;       // add counters
        if (ctx->t[0] < ctx->c) {  // carry overflow ?
          ctx->t[1]++;             // high word
        }
        blake2b_compress(ctx, 0);  // compress (not last)
        ctx->c = 0;                // counter to zero
      }
      ctx->b[ctx->c++] = ((const uint8_t *)in)[i];
    }
  }

  // Generate the message digest (size given in init).
  //      Result placed in "out".

  void blake2b_final(blake2b_ctx *ctx, void *out) {
    size_t i;

    ctx->t[0] += ctx->c;       // mark last block offset
    if (ctx->t[0] < ctx->c) {  // carry overflow
      ctx->t[1]++;             // high word
    }

    while (ctx->c < 128) {  // fill up with zeros
      ctx->b[ctx->c++] = 0;
    }
    blake2b_compress(ctx, 1);  // final block flag = 1

    // little endian convert and store
    for (i = 0; i < ctx->outlen; i++) {
      ((uint8_t *)out)[i] = (ctx->h[i >> 3] >> (8 * (i & 7))) & 0xFF;
    }
  }

  // Convenience function for all-in-one computation.

  int blake2b(void *out,
              size_t outlen,
              const void *key,
              size_t keylen,
              const void *in,
              size_t inlen) {
    blake2b_ctx ctx;

    if (blake2b_init(&ctx, outlen, key, keylen)) {
      return -1;
    }
    blake2b_update(&ctx, in, inlen);
    blake2b_final(&ctx, out);

    return 0;
  }

}  // namespace kagome::crypto