text: /*
   * Copyright 2009 Colin Persocialnodeal, 2011 ArtForz, 2012-2013 pooler
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXSMNLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * This file was originally written by Colin Persocialnodeal as part of the Tarsnap
   * online backup system.
   */
  
  #include "crypto/scrypt.h"
  #include "uint256.h"
  #include "utilstrencodings.h"
  #include <openssl/sha.h>
  #include <string>
  
  #include <string.h>
  #include <stdint.h>
  
  #ifndef __FreeBSD__
  static inline void be32enc(void *pp, uint32_t x)
  {
      uint8_t *p = (uint8_t *)pp;
      p[3] = x & 0xff;
      p[2] = (x >> 8) & 0xff;
      p[1] = (x >> 16) & 0xff;
      p[0] = (x >> 24) & 0xff;
  }
  #endif
  
  typedef struct HMAC_SHA256Context {
      SHA256_CTX ictx;
      SHA256_CTX octx;
  } HMAC_SHA256_CTX;
  
  /* Initialize an HMAC-SHA256 operation with the given key. */
  static void
  HMAC_SHA256_Init(HMAC_SHA256_CTX *ctx, const void *_K, size_t Klen)
  {
      unsigned char pad[64];
      unsigned char khash[32];
      const unsigned char *K = (const unsigned char *)_K;
      size_t i;
  
      /* If Klen > 64, the key is really SHA256(K). */
      if (Klen > 64) {
          SHA256_Init(&ctx->ictx);
          SHA256_Update(&ctx->ictx, K, Klen);
          SHA256_Final(khash, &ctx->ictx);
          K = khash;
          Klen = 32;
      }
  
      /* Inner SHA256 operation is SHA256(K xor [block of 0x36] || data). */
      SHA256_Init(&ctx->ictx);
      memset(pad, 0x36, 64);
      for (i = 0; i < Klen; i++)
          pad[i] ^= K[i];
      SHA256_Update(&ctx->ictx, pad, 64);
  
      /* Outer SHA256 operation is SHA256(K xor [block of 0x5c] || hash). */
      SHA256_Init(&ctx->octx);
      memset(pad, 0x5c, 64);
      for (i = 0; i < Klen; i++)
          pad[i] ^= K[i];
      SHA256_Update(&ctx->octx, pad, 64);
  
      /* Clean the stack. */
      memset(khash, 0, 32);
  }
  
  /* Add bytes to the HMAC-SHA256 operation. */
  static void
  HMAC_SHA256_Update(HMAC_SHA256_CTX *ctx, const void *in, size_t len)
  {
      /* Feed data to the inner SHA256 operation. */
      SHA256_Update(&ctx->ictx, in, len);
  }
  
  /* Finish an HMAC-SHA256 operation. */
  static void
  HMAC_SHA256_Final(unsigned char digest[32], HMAC_SHA256_CTX *ctx)
  {
      unsigned char ihash[32];
  
      /* Finish the inner SHA256 operation. */
      SHA256_Final(ihash, &ctx->ictx);
  
      /* Feed the inner hash to the outer SHA256 operation. */
      SHA256_Update(&ctx->octx, ihash, 32);
  
      /* Finish the outer SHA256 operation. */
      SHA256_Final(digest, &ctx->octx);
  
      /* Clean the stack. */
      memset(ihash, 0, 32);
  }
  
  /**
   * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
   * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
   * write the output to buf.  The value dkLen must be at most 32 * (2^32 - 1).
   */
  void
  PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, const uint8_t *salt,
                size_t saltlen, uint64_t c, uint8_t *buf, size_t dkLen)
  {
      HMAC_SHA256_CTX PShctx, hctx;
      size_t i;
      uint8_t ivec[4];
      uint8_t U[32];
      uint8_t T[32];
      uint64_t j;
      int k;
      size_t clen;
  
      /* Compute HMAC state after processing P and S. */
      HMAC_SHA256_Init(&PShctx, passwd, passwdlen);
      HMAC_SHA256_Update(&PShctx, salt, saltlen);
  
      /* Iterate through the blocks. */
      for (i = 0; i * 32 < dkLen; i++) {
          /* Generate INT(i + 1). */
          be32enc(ivec, (uint32_t)(i + 1));
  
          /* Compute U_1 = PRF(P, S || INT(i)). */
          memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX));
          HMAC_SHA256_Update(&hctx, ivec, 4);
          HMAC_SHA256_Final(U, &hctx);
  
          /* T_i = U_1 ... */
          memcpy(T, U, 32);
  
          for (j = 2; j <= c; j++) {
              /* Compute U_j. */
              HMAC_SHA256_Init(&hctx, passwd, passwdlen);
              HMAC_SHA256_Update(&hctx, U, 32);
              HMAC_SHA256_Final(U, &hctx);
  
              /* ... xor U_j ... */
              for (k = 0; k < 32; k++)
                  T[k] ^= U[k];
          }
  
          /* Copy as many bytes as necessary into buf. */
          clen = dkLen - i * 32;
          if (clen > 32)
              clen = 32;
          memcpy(&buf[i * 32], T, clen);
      }
  
      /* Clean PShctx, since we never called _Final on it. */
      memset(&PShctx, 0, sizeof(HMAC_SHA256_CTX));
  }
  
  static inline uint32_t
  le32dec_2(const void * pp)
  {
      const uint8_t * p = (uint8_t const *)pp;
  
      return ((uint32_t)(p[0]) + ((uint32_t)(p[1]) << 8) +
              ((uint32_t)(p[2]) << 16) + ((uint32_t)(p[3]) << 24));
  }
  
  static inline void
  le32enc_2(void * pp, uint32_t x)
  {
      uint8_t * p = (uint8_t *)pp;
  
      p[0] = x & 0xff;
      p[1] = (x >> 8) & 0xff;
      p[2] = (x >> 16) & 0xff;
      p[3] = (x >> 24) & 0xff;
  }
  
  static void
  blkcpy(void * dest, const void * src, size_t len)
  {
      size_t * D = (size_t*)dest;
      const size_t * S = (size_t*)src;
      size_t L = len / sizeof(size_t);
      size_t i;
  
      for (i = 0; i < L; i++)
          D[i] = S[i];
  }
  
  static void
  blkxor(void * dest, const void * src, size_t len)
  {
      size_t * D = (size_t*)dest;
      const size_t* S = (size_t*)src;
      size_t L = len / sizeof(size_t);
      size_t i;
  
      for (i = 0; i < L; i++)
          D[i] ^= S[i];
  }
  
  /**
   * salsa20_8(B):
   * Apply the salsa20/8 core to the provided block.
   */
  static void
  salsa20_8(uint32_t B[16])
  {
      uint32_t x[16];
      size_t i;
  
      blkcpy(x, B, 64);
      for (i = 0; i < 8; i += 2) {
  #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
          /* Operate on columns. */
          x[ 4] ^= R(x[ 0]+x[12], 7);  x[ 8] ^= R(x[ 4]+x[ 0], 9);
          x[12] ^= R(x[ 8]+x[ 4],13);  x[ 0] ^= R(x[12]+x[ 8],18);
  
          x[ 9] ^= R(x[ 5]+x[ 1], 7);  x[13] ^= R(x[ 9]+x[ 5], 9);
          x[ 1] ^= R(x[13]+x[ 9],13);  x[ 5] ^= R(x[ 1]+x[13],18);
  
          x[14] ^= R(x[10]+x[ 6], 7);  x[ 2] ^= R(x[14]+x[10], 9);
          x[ 6] ^= R(x[ 2]+x[14],13);  x[10] ^= R(x[ 6]+x[ 2],18);
  
          x[ 3] ^= R(x[15]+x[11], 7);  x[ 7] ^= R(x[ 3]+x[15], 9);
          x[11] ^= R(x[ 7]+x[ 3],13);  x[15] ^= R(x[11]+x[ 7],18);
  
          /* Operate on rows. */
          x[ 1] ^= R(x[ 0]+x[ 3], 7);  x[ 2] ^= R(x[ 1]+x[ 0], 9);
          x[ 3] ^= R(x[ 2]+x[ 1],13);  x[ 0] ^= R(x[ 3]+x[ 2],18);
  
          x[ 6] ^= R(x[ 5]+x[ 4], 7);  x[ 7] ^= R(x[ 6]+x[ 5], 9);
          x[ 4] ^= R(x[ 7]+x[ 6],13);  x[ 5] ^= R(x[ 4]+x[ 7],18);
  
          x[11] ^= R(x[10]+x[ 9], 7);  x[ 8] ^= R(x[11]+x[10], 9);
          x[ 9] ^= R(x[ 8]+x[11],13);  x[10] ^= R(x[ 9]+x[ 8],18);
  
          x[12] ^= R(x[15]+x[14], 7);  x[13] ^= R(x[12]+x[15], 9);
          x[14] ^= R(x[13]+x[12],13);  x[15] ^= R(x[14]+x[13],18);
  #undef R
      }
      for (i = 0; i < 16; i++)
          B[i] += x[i];
  }
  
  /**
   * blockmix_salsa8(Bin, Bout, X, r):
   * Compute Bout = BlockMix_{salsa20/8, r}(Bin).  The input Bin must be 128r
   * bytes in length; the output Bout must also be the same size.  The
   * temporary space X must be 64 bytes.
   */
  static void
  blockmix_salsa8(const uint32_t * Bin, uint32_t * Bout, uint32_t * X, size_t r)
  {
      size_t i;
  
      /* 1: X <-- B_{2r - 1} */
      blkcpy(X, &Bin[(2 * r - 1) * 16], 64);
  
      /* 2: for i = 0 to 2r - 1 do */
      for (i = 0; i < 2 * r; i += 2) {
          /* 3: X <-- H(X \xor B_i) */
          blkxor(X, &Bin[i * 16], 64);
          salsa20_8(X);
  
          /* 4: Y_i <-- X */
          /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */
          blkcpy(&Bout[i * 8], X, 64);
  
          /* 3: X <-- H(X \xor B_i) */
          blkxor(X, &Bin[i * 16 + 16], 64);
          salsa20_8(X);
  
          /* 4: Y_i <-- X */
          /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */
          blkcpy(&Bout[i * 8 + r * 16], X, 64);
      }
  }
  
  /**
   * integerify(B, r):
   * Return the result of parsing B_{2r-1} as a little-endian integer.
   */
  static uint64_t
  integerify(const void * B, size_t r)
  {
      const uint32_t * X = (const uint32_t*)((uintptr_t)(B) + (2 * r - 1) * 64);
  
      return (((uint64_t)(X[1]) << 32) + X[0]);
  }
  
  void SMix(uint8_t *B, unsigned int r, unsigned int N, void* _V, void* XY)
  {
      //new
      uint32_t* X = (uint32_t*)XY;
      uint32_t* Y = (uint32_t*)((uint8_t*)(XY) + 128 * r);
      uint32_t* Z = (uint32_t*)((uint8_t *)(XY) + 256 * r);
      uint32_t * V = (uint32_t*)_V;
  
      uint32_t j, k;
  
      /* 1: X <-- B */
      for (k = 0; k < 32 * r; k++)
          X[k] = le32dec_2(&B[4 * k]);
  
      /* 2: for i = 0 to N - 1 do */
      for (unsigned int i = 0; i < N; i += 2)
      {
          /* 3: V_i <-- X */
          blkcpy(&V[i * (32 * r)], X, 128 * r);
  
          /* 4: X <-- H(X) */
          blockmix_salsa8(X, Y, Z, r);
  
          /* 3: V_i <-- X */
          blkcpy(&V[(i + 1) * (32 * r)], Y, 128 * r);
  
          /* 4: X <-- H(X) */
          blockmix_salsa8(Y, X, Z, r);
      }
  
      /* 6: for i = 0 to N - 1 do */
      for (unsigned int i = 0; i < N; i += 2)
      {
          /* 7: j <-- Integerify(X) mod N */
          j = integerify(X, r) & (N - 1);
  
          /* 8: X <-- H(X \xor V_j) */
          blkxor(X, &V[j * (32 * r)], 128 * r);
          blockmix_salsa8(X, Y, Z, r);
  
          /* 7: j <-- Integerify(X) mod N */
          j = integerify(Y, r) & (N - 1);
  
          /* 8: X <-- H(X \xor V_j) */
          blkxor(Y, &V[j * (32 * r)], 128 * r);
          blockmix_salsa8(Y, X, Z, r);
      }
  
      /* 10: B' <-- X */
      for (k = 0; k < 32 * r; k++)
          le32enc_2(&B[4 * k], X[k]);
  }
  
  void scrypt(const char* pass, unsigned int pLen, const char* salt, unsigned int sLen, char *output, unsigned int N, unsigned int r, unsigned int p, unsigned int dkLen)
  {
      //containers
      void* V0 = malloc(128 * r * N + 63);
      void* XY0 = malloc(256 * r + 64 + 63);
      void* B1 = malloc(128 * r * p + 63);
      uint8_t* B = (uint8_t *)(((uintptr_t)(B1) + 63) & ~ (uintptr_t)(63));
      uint32_t* V = (uint32_t *)(((uintptr_t)(V0) + 63) & ~ (uintptr_t)(63));
      uint32_t* XY = (uint32_t *)(((uintptr_t)(XY0) + 63) & ~ (uintptr_t)(63));
  
      PBKDF2_SHA256((const uint8_t *)pass, pLen, (const uint8_t *)salt, sLen, 1, B, p * 128 * r);
  
      for(unsigned int i = 0; i < p; i++)
      {
          SMix(&B[i * 128 * r], r, N, V, XY);
      }
  
      PBKDF2_SHA256((const uint8_t *)pass, pLen, B, p * 128 * r, 1, (uint8_t *)output, dkLen);
  
      free(V0);
      free(XY0);
      free(B1);
  }
  