library/sha256.c - security/mbedtls - Rivoreo Source Code Repositories

 /*
  *  FIPS-180-2 compliant SHA-256 implementation
  *
  *  Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
  *
  *  This file is part of mbed TLS (https://www.polarssl.org)
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 /*
  *  The SHA-256 Secure Hash Standard was published by NIST in 2002.
  *
  *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
  */

 #if !defined(POLARSSL_CONFIG_FILE)
 #include "polarssl/config.h"
 #else
 #include POLARSSL_CONFIG_FILE
 #endif

 #if defined(POLARSSL_SHA256_C)

 #include "polarssl/sha256.h"

 #if defined(POLARSSL_FS_IO) || defined(POLARSSL_SELF_TEST)
 #include <stdio.h>
 #endif

 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
 #define polarssl_printf printf
 #endif

 /* Implementation that should never be optimized out by the compiler */
 static void polarssl_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }

 #if !defined(POLARSSL_SHA256_ALT)

 /*
  * 32-bit integer manipulation macros (big endian)
  */
 #ifndef GET_UINT32_BE
 #define GET_UINT32_BE(n,b,i)                            \
 {                                                       \
     (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
         | ( (uint32_t) (b)[(i) + 1] << 16 )             \
         | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
         | ( (uint32_t) (b)[(i) + 3]       );            \
 }
 #endif

 #ifndef PUT_UINT32_BE
 #define PUT_UINT32_BE(n,b,i)                            \
 {                                                       \
     (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
     (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
     (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
     (b)[(i) + 3] = (unsigned char) ( (n)       );       \
 }
 #endif

 void sha256_init( sha256_context *ctx )
 {
     memset( ctx, 0, sizeof( sha256_context ) );
 }

 void sha256_free( sha256_context *ctx )
 {
     if( ctx == NULL )
         return;

     polarssl_zeroize( ctx, sizeof( sha256_context ) );
 }

 /*
  * SHA-256 context setup
  */
 void sha256_starts( sha256_context *ctx, int is224 )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;

     if( is224 == 0 )
     {
         /* SHA-256 */
         ctx->state[0] = 0x6A09E667;
         ctx->state[1] = 0xBB67AE85;
         ctx->state[2] = 0x3C6EF372;
         ctx->state[3] = 0xA54FF53A;
         ctx->state[4] = 0x510E527F;
         ctx->state[5] = 0x9B05688C;
         ctx->state[6] = 0x1F83D9AB;
         ctx->state[7] = 0x5BE0CD19;
     }
     else
     {
         /* SHA-224 */
         ctx->state[0] = 0xC1059ED8;
         ctx->state[1] = 0x367CD507;
         ctx->state[2] = 0x3070DD17;
         ctx->state[3] = 0xF70E5939;
         ctx->state[4] = 0xFFC00B31;
         ctx->state[5] = 0x68581511;
         ctx->state[6] = 0x64F98FA7;
         ctx->state[7] = 0xBEFA4FA4;
     }

     ctx->is224 = is224;
 }

 void sha256_process( sha256_context *ctx, const unsigned char data[64] )
 {
     uint32_t temp1, temp2, W[64];
     uint32_t A, B, C, D, E, F, G, H;

     GET_UINT32_BE( W[ 0], data,  0 );
     GET_UINT32_BE( W[ 1], data,  4 );
     GET_UINT32_BE( W[ 2], data,  8 );
     GET_UINT32_BE( W[ 3], data, 12 );
     GET_UINT32_BE( W[ 4], data, 16 );
     GET_UINT32_BE( W[ 5], data, 20 );
     GET_UINT32_BE( W[ 6], data, 24 );
     GET_UINT32_BE( W[ 7], data, 28 );
     GET_UINT32_BE( W[ 8], data, 32 );
     GET_UINT32_BE( W[ 9], data, 36 );
     GET_UINT32_BE( W[10], data, 40 );
     GET_UINT32_BE( W[11], data, 44 );
     GET_UINT32_BE( W[12], data, 48 );
     GET_UINT32_BE( W[13], data, 52 );
     GET_UINT32_BE( W[14], data, 56 );
     GET_UINT32_BE( W[15], data, 60 );

 #define  SHR(x,n) ((x & 0xFFFFFFFF) >> n)
 #define ROTR(x,n) (SHR(x,n) | (x << (32 - n)))

 #define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^  SHR(x, 3))
 #define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^  SHR(x,10))

 #define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
 #define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

 #define F0(x,y,z) ((x & y) | (z & (x | y)))
 #define F1(x,y,z) (z ^ (x & (y ^ z)))

 #define R(t)                                    \
 (                                               \
     W[t] = S1(W[t -  2]) + W[t -  7] +          \
            S0(W[t - 15]) + W[t - 16]            \
 )

 #define P(a,b,c,d,e,f,g,h,x,K)                  \
 {                                               \
     temp1 = h + S3(e) + F1(e,f,g) + K + x;      \
     temp2 = S2(a) + F0(a,b,c);                  \
     d += temp1; h = temp1 + temp2;              \
 }

     A = ctx->state[0];
     B = ctx->state[1];
     C = ctx->state[2];
     D = ctx->state[3];
     E = ctx->state[4];
     F = ctx->state[5];
     G = ctx->state[6];
     H = ctx->state[7];

     P( A, B, C, D, E, F, G, H, W[ 0], 0x428A2F98 );
     P( H, A, B, C, D, E, F, G, W[ 1], 0x71374491 );
     P( G, H, A, B, C, D, E, F, W[ 2], 0xB5C0FBCF );
     P( F, G, H, A, B, C, D, E, W[ 3], 0xE9B5DBA5 );
     P( E, F, G, H, A, B, C, D, W[ 4], 0x3956C25B );
     P( D, E, F, G, H, A, B, C, W[ 5], 0x59F111F1 );
     P( C, D, E, F, G, H, A, B, W[ 6], 0x923F82A4 );
     P( B, C, D, E, F, G, H, A, W[ 7], 0xAB1C5ED5 );
     P( A, B, C, D, E, F, G, H, W[ 8], 0xD807AA98 );
     P( H, A, B, C, D, E, F, G, W[ 9], 0x12835B01 );
     P( G, H, A, B, C, D, E, F, W[10], 0x243185BE );
     P( F, G, H, A, B, C, D, E, W[11], 0x550C7DC3 );
     P( E, F, G, H, A, B, C, D, W[12], 0x72BE5D74 );
     P( D, E, F, G, H, A, B, C, W[13], 0x80DEB1FE );
     P( C, D, E, F, G, H, A, B, W[14], 0x9BDC06A7 );
     P( B, C, D, E, F, G, H, A, W[15], 0xC19BF174 );
     P( A, B, C, D, E, F, G, H, R(16), 0xE49B69C1 );
     P( H, A, B, C, D, E, F, G, R(17), 0xEFBE4786 );
     P( G, H, A, B, C, D, E, F, R(18), 0x0FC19DC6 );
     P( F, G, H, A, B, C, D, E, R(19), 0x240CA1CC );
     P( E, F, G, H, A, B, C, D, R(20), 0x2DE92C6F );
     P( D, E, F, G, H, A, B, C, R(21), 0x4A7484AA );
     P( C, D, E, F, G, H, A, B, R(22), 0x5CB0A9DC );
     P( B, C, D, E, F, G, H, A, R(23), 0x76F988DA );
     P( A, B, C, D, E, F, G, H, R(24), 0x983E5152 );
     P( H, A, B, C, D, E, F, G, R(25), 0xA831C66D );
     P( G, H, A, B, C, D, E, F, R(26), 0xB00327C8 );
     P( F, G, H, A, B, C, D, E, R(27), 0xBF597FC7 );
     P( E, F, G, H, A, B, C, D, R(28), 0xC6E00BF3 );
     P( D, E, F, G, H, A, B, C, R(29), 0xD5A79147 );
     P( C, D, E, F, G, H, A, B, R(30), 0x06CA6351 );
     P( B, C, D, E, F, G, H, A, R(31), 0x14292967 );
     P( A, B, C, D, E, F, G, H, R(32), 0x27B70A85 );
     P( H, A, B, C, D, E, F, G, R(33), 0x2E1B2138 );
     P( G, H, A, B, C, D, E, F, R(34), 0x4D2C6DFC );
     P( F, G, H, A, B, C, D, E, R(35), 0x53380D13 );
     P( E, F, G, H, A, B, C, D, R(36), 0x650A7354 );
     P( D, E, F, G, H, A, B, C, R(37), 0x766A0ABB );
     P( C, D, E, F, G, H, A, B, R(38), 0x81C2C92E );
     P( B, C, D, E, F, G, H, A, R(39), 0x92722C85 );
     P( A, B, C, D, E, F, G, H, R(40), 0xA2BFE8A1 );
     P( H, A, B, C, D, E, F, G, R(41), 0xA81A664B );
     P( G, H, A, B, C, D, E, F, R(42), 0xC24B8B70 );
     P( F, G, H, A, B, C, D, E, R(43), 0xC76C51A3 );
     P( E, F, G, H, A, B, C, D, R(44), 0xD192E819 );
     P( D, E, F, G, H, A, B, C, R(45), 0xD6990624 );
     P( C, D, E, F, G, H, A, B, R(46), 0xF40E3585 );
     P( B, C, D, E, F, G, H, A, R(47), 0x106AA070 );
     P( A, B, C, D, E, F, G, H, R(48), 0x19A4C116 );
     P( H, A, B, C, D, E, F, G, R(49), 0x1E376C08 );
     P( G, H, A, B, C, D, E, F, R(50), 0x2748774C );
     P( F, G, H, A, B, C, D, E, R(51), 0x34B0BCB5 );
     P( E, F, G, H, A, B, C, D, R(52), 0x391C0CB3 );
     P( D, E, F, G, H, A, B, C, R(53), 0x4ED8AA4A );
     P( C, D, E, F, G, H, A, B, R(54), 0x5B9CCA4F );
     P( B, C, D, E, F, G, H, A, R(55), 0x682E6FF3 );
     P( A, B, C, D, E, F, G, H, R(56), 0x748F82EE );
     P( H, A, B, C, D, E, F, G, R(57), 0x78A5636F );
     P( G, H, A, B, C, D, E, F, R(58), 0x84C87814 );
     P( F, G, H, A, B, C, D, E, R(59), 0x8CC70208 );
     P( E, F, G, H, A, B, C, D, R(60), 0x90BEFFFA );
     P( D, E, F, G, H, A, B, C, R(61), 0xA4506CEB );
     P( C, D, E, F, G, H, A, B, R(62), 0xBEF9A3F7 );
     P( B, C, D, E, F, G, H, A, R(63), 0xC67178F2 );

     ctx->state[0] += A;
     ctx->state[1] += B;
     ctx->state[2] += C;
     ctx->state[3] += D;
     ctx->state[4] += E;
     ctx->state[5] += F;
     ctx->state[6] += G;
     ctx->state[7] += H;
 }

 /*
  * SHA-256 process buffer
  */
 void sha256_update( sha256_context *ctx, const unsigned char *input,
                     size_t ilen )
 {
     size_t fill;
     uint32_t left;

     if( ilen == 0 )
         return;

     left = ctx->total[0] & 0x3F;
     fill = 64 - left;

     ctx->total[0] += (uint32_t) ilen;
     ctx->total[0] &= 0xFFFFFFFF;

     if( ctx->total[0] < (uint32_t) ilen )
         ctx->total[1]++;

     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
         sha256_process( ctx, ctx->buffer );
         input += fill;
         ilen  -= fill;
         left = 0;
     }

     while( ilen >= 64 )
     {
         sha256_process( ctx, input );
         input += 64;
         ilen  -= 64;
     }

     if( ilen > 0 )
         memcpy( (void *) (ctx->buffer + left), input, ilen );
 }

 static const unsigned char sha256_padding[64] =
 {
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };

 /*
  * SHA-256 final digest
  */
 void sha256_finish( sha256_context *ctx, unsigned char output[32] )
 {
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];

     high = ( ctx->total[0] >> 29 )
          | ( ctx->total[1] <<  3 );
     low  = ( ctx->total[0] <<  3 );

     PUT_UINT32_BE( high, msglen, 0 );
     PUT_UINT32_BE( low,  msglen, 4 );

     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );

     sha256_update( ctx, sha256_padding, padn );
     sha256_update( ctx, msglen, 8 );

     PUT_UINT32_BE( ctx->state[0], output,  0 );
     PUT_UINT32_BE( ctx->state[1], output,  4 );
     PUT_UINT32_BE( ctx->state[2], output,  8 );
     PUT_UINT32_BE( ctx->state[3], output, 12 );
     PUT_UINT32_BE( ctx->state[4], output, 16 );
     PUT_UINT32_BE( ctx->state[5], output, 20 );
     PUT_UINT32_BE( ctx->state[6], output, 24 );

     if( ctx->is224 == 0 )
         PUT_UINT32_BE( ctx->state[7], output, 28 );
 }

 #endif /* !POLARSSL_SHA256_ALT */

 /*
  * output = SHA-256( input buffer )
  */
 void sha256( const unsigned char *input, size_t ilen,
              unsigned char output[32], int is224 )
 {
     sha256_context ctx;

     sha256_init( &ctx );
     sha256_starts( &ctx, is224 );
     sha256_update( &ctx, input, ilen );
     sha256_finish( &ctx, output );
     sha256_free( &ctx );
 }

 #if defined(POLARSSL_FS_IO)
 /*
  * output = SHA-256( file contents )
  */
 int sha256_file( const char *path, unsigned char output[32], int is224 )
 {
     FILE *f;
     size_t n;
     sha256_context ctx;
     unsigned char buf[1024];

     if( ( f = fopen( path, "rb" ) ) == NULL )
         return( POLARSSL_ERR_SHA256_FILE_IO_ERROR );

     sha256_init( &ctx );
     sha256_starts( &ctx, is224 );

     while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
         sha256_update( &ctx, buf, n );

     sha256_finish( &ctx, output );
     sha256_free( &ctx );

     if( ferror( f ) != 0 )
     {
         fclose( f );
         return( POLARSSL_ERR_SHA256_FILE_IO_ERROR );
     }

     fclose( f );
     return( 0 );
 }
 #endif /* POLARSSL_FS_IO */

 /*
  * SHA-256 HMAC context setup
  */
 void sha256_hmac_starts( sha256_context *ctx, const unsigned char *key,
                          size_t keylen, int is224 )
 {
     size_t i;
     unsigned char sum[32];

     if( keylen > 64 )
     {
         sha256( key, keylen, sum, is224 );
         keylen = ( is224 ) ? 28 : 32;
         key = sum;
     }

     memset( ctx->ipad, 0x36, 64 );
     memset( ctx->opad, 0x5C, 64 );

     for( i = 0; i < keylen; i++ )
     {
         ctx->ipad[i] = (unsigned char)( ctx->ipad[i] ^ key[i] );
         ctx->opad[i] = (unsigned char)( ctx->opad[i] ^ key[i] );
     }

     sha256_starts( ctx, is224 );
     sha256_update( ctx, ctx->ipad, 64 );

     polarssl_zeroize( sum, sizeof( sum ) );
 }

 /*
  * SHA-256 HMAC process buffer
  */
 void sha256_hmac_update( sha256_context *ctx, const unsigned char *input,
                          size_t ilen )
 {
     sha256_update( ctx, input, ilen );
 }

 /*
  * SHA-256 HMAC final digest
  */
 void sha256_hmac_finish( sha256_context *ctx, unsigned char output[32] )
 {
     int is224, hlen;
     unsigned char tmpbuf[32];

     is224 = ctx->is224;
     hlen = ( is224 == 0 ) ? 32 : 28;

     sha256_finish( ctx, tmpbuf );
     sha256_starts( ctx, is224 );
     sha256_update( ctx, ctx->opad, 64 );
     sha256_update( ctx, tmpbuf, hlen );
     sha256_finish( ctx, output );

     polarssl_zeroize( tmpbuf, sizeof( tmpbuf ) );
 }

 /*
  * SHA-256 HMAC context reset
  */
 void sha256_hmac_reset( sha256_context *ctx )
 {
     sha256_starts( ctx, ctx->is224 );
     sha256_update( ctx, ctx->ipad, 64 );
 }

 /*
  * output = HMAC-SHA-256( hmac key, input buffer )
  */
 void sha256_hmac( const unsigned char *key, size_t keylen,
                   const unsigned char *input, size_t ilen,
                   unsigned char output[32], int is224 )
 {
     sha256_context ctx;

     sha256_init( &ctx );
     sha256_hmac_starts( &ctx, key, keylen, is224 );
     sha256_hmac_update( &ctx, input, ilen );
     sha256_hmac_finish( &ctx, output );
     sha256_free( &ctx );
 }

 #if defined(POLARSSL_SELF_TEST)
 /*
  * FIPS-180-2 test vectors
  */
 static unsigned char sha256_test_buf[3][57] =
 {
     { "abc" },
     { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" },
     { "" }
 };

 static const int sha256_test_buflen[3] =
 {
     3, 56, 1000
 };

 static const unsigned char sha256_test_sum[6][32] =
 {
     /*
      * SHA-224 test vectors
      */
     { 0x23, 0x09, 0x7D, 0x22, 0x34, 0x05, 0xD8, 0x22,
       0x86, 0x42, 0xA4, 0x77, 0xBD, 0xA2, 0x55, 0xB3,
       0x2A, 0xAD, 0xBC, 0xE4, 0xBD, 0xA0, 0xB3, 0xF7,
       0xE3, 0x6C, 0x9D, 0xA7 },
     { 0x75, 0x38, 0x8B, 0x16, 0x51, 0x27, 0x76, 0xCC,
       0x5D, 0xBA, 0x5D, 0xA1, 0xFD, 0x89, 0x01, 0x50,
       0xB0, 0xC6, 0x45, 0x5C, 0xB4, 0xF5, 0x8B, 0x19,
       0x52, 0x52, 0x25, 0x25 },
     { 0x20, 0x79, 0x46, 0x55, 0x98, 0x0C, 0x91, 0xD8,
       0xBB, 0xB4, 0xC1, 0xEA, 0x97, 0x61, 0x8A, 0x4B,
       0xF0, 0x3F, 0x42, 0x58, 0x19, 0x48, 0xB2, 0xEE,
       0x4E, 0xE7, 0xAD, 0x67 },

     /*
      * SHA-256 test vectors
      */
     { 0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA,
       0x41, 0x41, 0x40, 0xDE, 0x5D, 0xAE, 0x22, 0x23,
       0xB0, 0x03, 0x61, 0xA3, 0x96, 0x17, 0x7A, 0x9C,
       0xB4, 0x10, 0xFF, 0x61, 0xF2, 0x00, 0x15, 0xAD },
     { 0x24, 0x8D, 0x6A, 0x61, 0xD2, 0x06, 0x38, 0xB8,
       0xE5, 0xC0, 0x26, 0x93, 0x0C, 0x3E, 0x60, 0x39,
       0xA3, 0x3C, 0xE4, 0x59, 0x64, 0xFF, 0x21, 0x67,
       0xF6, 0xEC, 0xED, 0xD4, 0x19, 0xDB, 0x06, 0xC1 },
     { 0xCD, 0xC7, 0x6E, 0x5C, 0x99, 0x14, 0xFB, 0x92,
       0x81, 0xA1, 0xC7, 0xE2, 0x84, 0xD7, 0x3E, 0x67,
       0xF1, 0x80, 0x9A, 0x48, 0xA4, 0x97, 0x20, 0x0E,
       0x04, 0x6D, 0x39, 0xCC, 0xC7, 0x11, 0x2C, 0xD0 }
 };

 /*
  * RFC 4231 test vectors
  */
 static unsigned char sha256_hmac_test_key[7][26] =
 {
     { "\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B"
       "\x0B\x0B\x0B\x0B" },
     { "Jefe" },
     { "\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA"
       "\xAA\xAA\xAA\xAA" },
     { "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\x10"
       "\x11\x12\x13\x14\x15\x16\x17\x18\x19" },
     { "\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C"
       "\x0C\x0C\x0C\x0C" },
     { "" }, /* 0xAA 131 times */
     { "" }
 };

 static const int sha256_hmac_test_keylen[7] =
 {
     20, 4, 20, 25, 20, 131, 131
 };

 static unsigned char sha256_hmac_test_buf[7][153] =
 {
     { "Hi There" },
     { "what do ya want for nothing?" },
     { "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
       "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
       "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
       "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
       "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD" },
     { "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
       "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
       "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
       "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
       "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD" },
     { "Test With Truncation" },
     { "Test Using Larger Than Block-Size Key - Hash Key First" },
     { "This is a test using a larger than block-size key "
       "and a larger than block-size data. The key needs to "
       "be hashed before being used by the HMAC algorithm." }
 };

 static const int sha256_hmac_test_buflen[7] =
 {
     8, 28, 50, 50, 20, 54, 152
 };

 static const unsigned char sha256_hmac_test_sum[14][32] =
 {
     /*
      * HMAC-SHA-224 test vectors
      */
     { 0x89, 0x6F, 0xB1, 0x12, 0x8A, 0xBB, 0xDF, 0x19,
       0x68, 0x32, 0x10, 0x7C, 0xD4, 0x9D, 0xF3, 0x3F,
       0x47, 0xB4, 0xB1, 0x16, 0x99, 0x12, 0xBA, 0x4F,
       0x53, 0x68, 0x4B, 0x22 },
     { 0xA3, 0x0E, 0x01, 0x09, 0x8B, 0xC6, 0xDB, 0xBF,
       0x45, 0x69, 0x0F, 0x3A, 0x7E, 0x9E, 0x6D, 0x0F,
       0x8B, 0xBE, 0xA2, 0xA3, 0x9E, 0x61, 0x48, 0x00,
       0x8F, 0xD0, 0x5E, 0x44 },
     { 0x7F, 0xB3, 0xCB, 0x35, 0x88, 0xC6, 0xC1, 0xF6,
       0xFF, 0xA9, 0x69, 0x4D, 0x7D, 0x6A, 0xD2, 0x64,
       0x93, 0x65, 0xB0, 0xC1, 0xF6, 0x5D, 0x69, 0xD1,
       0xEC, 0x83, 0x33, 0xEA },
     { 0x6C, 0x11, 0x50, 0x68, 0x74, 0x01, 0x3C, 0xAC,
       0x6A, 0x2A, 0xBC, 0x1B, 0xB3, 0x82, 0x62, 0x7C,
       0xEC, 0x6A, 0x90, 0xD8, 0x6E, 0xFC, 0x01, 0x2D,
       0xE7, 0xAF, 0xEC, 0x5A },
     { 0x0E, 0x2A, 0xEA, 0x68, 0xA9, 0x0C, 0x8D, 0x37,
       0xC9, 0x88, 0xBC, 0xDB, 0x9F, 0xCA, 0x6F, 0xA8 },
     { 0x95, 0xE9, 0xA0, 0xDB, 0x96, 0x20, 0x95, 0xAD,
       0xAE, 0xBE, 0x9B, 0x2D, 0x6F, 0x0D, 0xBC, 0xE2,
       0xD4, 0x99, 0xF1, 0x12, 0xF2, 0xD2, 0xB7, 0x27,
       0x3F, 0xA6, 0x87, 0x0E },
     { 0x3A, 0x85, 0x41, 0x66, 0xAC, 0x5D, 0x9F, 0x02,
       0x3F, 0x54, 0xD5, 0x17, 0xD0, 0xB3, 0x9D, 0xBD,
       0x94, 0x67, 0x70, 0xDB, 0x9C, 0x2B, 0x95, 0xC9,
       0xF6, 0xF5, 0x65, 0xD1 },

     /*
      * HMAC-SHA-256 test vectors
      */
     { 0xB0, 0x34, 0x4C, 0x61, 0xD8, 0xDB, 0x38, 0x53,
       0x5C, 0xA8, 0xAF, 0xCE, 0xAF, 0x0B, 0xF1, 0x2B,
       0x88, 0x1D, 0xC2, 0x00, 0xC9, 0x83, 0x3D, 0xA7,
       0x26, 0xE9, 0x37, 0x6C, 0x2E, 0x32, 0xCF, 0xF7 },
     { 0x5B, 0xDC, 0xC1, 0x46, 0xBF, 0x60, 0x75, 0x4E,
       0x6A, 0x04, 0x24, 0x26, 0x08, 0x95, 0x75, 0xC7,
       0x5A, 0x00, 0x3F, 0x08, 0x9D, 0x27, 0x39, 0x83,
       0x9D, 0xEC, 0x58, 0xB9, 0x64, 0xEC, 0x38, 0x43 },
     { 0x77, 0x3E, 0xA9, 0x1E, 0x36, 0x80, 0x0E, 0x46,
       0x85, 0x4D, 0xB8, 0xEB, 0xD0, 0x91, 0x81, 0xA7,
       0x29, 0x59, 0x09, 0x8B, 0x3E, 0xF8, 0xC1, 0x22,
       0xD9, 0x63, 0x55, 0x14, 0xCE, 0xD5, 0x65, 0xFE },
     { 0x82, 0x55, 0x8A, 0x38, 0x9A, 0x44, 0x3C, 0x0E,
       0xA4, 0xCC, 0x81, 0x98, 0x99, 0xF2, 0x08, 0x3A,
       0x85, 0xF0, 0xFA, 0xA3, 0xE5, 0x78, 0xF8, 0x07,
       0x7A, 0x2E, 0x3F, 0xF4, 0x67, 0x29, 0x66, 0x5B },
     { 0xA3, 0xB6, 0x16, 0x74, 0x73, 0x10, 0x0E, 0xE0,
       0x6E, 0x0C, 0x79, 0x6C, 0x29, 0x55, 0x55, 0x2B },
     { 0x60, 0xE4, 0x31, 0x59, 0x1E, 0xE0, 0xB6, 0x7F,
       0x0D, 0x8A, 0x26, 0xAA, 0xCB, 0xF5, 0xB7, 0x7F,
       0x8E, 0x0B, 0xC6, 0x21, 0x37, 0x28, 0xC5, 0x14,
       0x05, 0x46, 0x04, 0x0F, 0x0E, 0xE3, 0x7F, 0x54 },
     { 0x9B, 0x09, 0xFF, 0xA7, 0x1B, 0x94, 0x2F, 0xCB,
       0x27, 0x63, 0x5F, 0xBC, 0xD5, 0xB0, 0xE9, 0x44,
       0xBF, 0xDC, 0x63, 0x64, 0x4F, 0x07, 0x13, 0x93,
       0x8A, 0x7F, 0x51, 0x53, 0x5C, 0x3A, 0x35, 0xE2 }
 };

 /*
  * Checkup routine
  */
 int sha256_self_test( int verbose )
 {
     int i, j, k, buflen, ret = 0;
     unsigned char buf[1024];
     unsigned char sha256sum[32];
     sha256_context ctx;

     sha256_init( &ctx );

     for( i = 0; i < 6; i++ )
     {
         j = i % 3;
         k = i < 3;

         if( verbose != 0 )
             polarssl_printf( "  SHA-%d test #%d: ", 256 - k * 32, j + 1 );

         sha256_starts( &ctx, k );

         if( j == 2 )
         {
             memset( buf, 'a', buflen = 1000 );

             for( j = 0; j < 1000; j++ )
                 sha256_update( &ctx, buf, buflen );
         }
         else
             sha256_update( &ctx, sha256_test_buf[j],
                                  sha256_test_buflen[j] );

         sha256_finish( &ctx, sha256sum );

         if( memcmp( sha256sum, sha256_test_sum[i], 32 - k * 4 ) != 0 )
         {
             if( verbose != 0 )
                 polarssl_printf( "failed\n" );

             ret = 1;
             goto exit;
         }

         if( verbose != 0 )
             polarssl_printf( "passed\n" );
     }

     if( verbose != 0 )
         polarssl_printf( "\n" );

     for( i = 0; i < 14; i++ )
     {
         j = i % 7;
         k = i < 7;

         if( verbose != 0 )
             polarssl_printf( "  HMAC-SHA-%d test #%d: ", 256 - k * 32, j + 1 );

         if( j == 5 || j == 6 )
         {
             memset( buf, '\xAA', buflen = 131 );
             sha256_hmac_starts( &ctx, buf, buflen, k );
         }
         else
             sha256_hmac_starts( &ctx, sha256_hmac_test_key[j],
                                       sha256_hmac_test_keylen[j], k );

         sha256_hmac_update( &ctx, sha256_hmac_test_buf[j],
                                   sha256_hmac_test_buflen[j] );

         sha256_hmac_finish( &ctx, sha256sum );

         buflen = ( j == 4 ) ? 16 : 32 - k * 4;

         if( memcmp( sha256sum, sha256_hmac_test_sum[i], buflen ) != 0 )
         {
             if( verbose != 0 )
                 polarssl_printf( "failed\n" );

             ret = 1;
             goto exit;
         }

         if( verbose != 0 )
             polarssl_printf( "passed\n" );
     }

     if( verbose != 0 )
         polarssl_printf( "\n" );

 exit:
     sha256_free( &ctx );

     return( ret );
 }

 #endif /* POLARSSL_SELF_TEST */

 #endif /* POLARSSL_SHA256_C */
	/*
	* FIPS-180-2 compliant SHA-256 implementation
	*
	* Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
	*
	* This file is part of mbed TLS (https://www.polarssl.org)
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	*/
	/*
	* The SHA-256 Secure Hash Standard was published by NIST in 2002.
	*
	* http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
	*/

	#if !defined(POLARSSL_CONFIG_FILE)
	#include "polarssl/config.h"
	#else
	#include POLARSSL_CONFIG_FILE
	#endif

	#if defined(POLARSSL_SHA256_C)

	#include "polarssl/sha256.h"

	#if defined(POLARSSL_FS_IO) \|\| defined(POLARSSL_SELF_TEST)
	#include <stdio.h>
	#endif

	#if defined(POLARSSL_PLATFORM_C)
	#include "polarssl/platform.h"
	#else
	#define polarssl_printf printf
	#endif

	/* Implementation that should never be optimized out by the compiler */
	static void polarssl_zeroize( void *v, size_t n ) {
	volatile unsigned char p = v; while( n-- ) p++ = 0;
	}

	#if !defined(POLARSSL_SHA256_ALT)

	/*
	* 32-bit integer manipulation macros (big endian)
	*/
	#ifndef GET_UINT32_BE
	#define GET_UINT32_BE(n,b,i) \
	{ \
	(n) = ( (uint32_t) (b)[(i) ] << 24 ) \
	\| ( (uint32_t) (b)[(i) + 1] << 16 ) \
	\| ( (uint32_t) (b)[(i) + 2] << 8 ) \
	\| ( (uint32_t) (b)[(i) + 3] ); \
	}
	#endif

	#ifndef PUT_UINT32_BE
	#define PUT_UINT32_BE(n,b,i) \
	{ \
	(b)[(i) ] = (unsigned char) ( (n) >> 24 ); \
	(b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \
	(b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \
	(b)[(i) + 3] = (unsigned char) ( (n) ); \
	}
	#endif

	void sha256_init( sha256_context *ctx )
	{
	memset( ctx, 0, sizeof( sha256_context ) );
	}

	void sha256_free( sha256_context *ctx )
	{
	if( ctx == NULL )
	return;

	polarssl_zeroize( ctx, sizeof( sha256_context ) );
	}

	/*
	* SHA-256 context setup
	*/
	void sha256_starts( sha256_context *ctx, int is224 )
	{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	if( is224 == 0 )
	{
	/* SHA-256 */
	ctx->state[0] = 0x6A09E667;
	ctx->state[1] = 0xBB67AE85;
	ctx->state[2] = 0x3C6EF372;
	ctx->state[3] = 0xA54FF53A;
	ctx->state[4] = 0x510E527F;
	ctx->state[5] = 0x9B05688C;
	ctx->state[6] = 0x1F83D9AB;
	ctx->state[7] = 0x5BE0CD19;
	}
	else
	{
	/* SHA-224 */
	ctx->state[0] = 0xC1059ED8;
	ctx->state[1] = 0x367CD507;
	ctx->state[2] = 0x3070DD17;
	ctx->state[3] = 0xF70E5939;
	ctx->state[4] = 0xFFC00B31;
	ctx->state[5] = 0x68581511;
	ctx->state[6] = 0x64F98FA7;
	ctx->state[7] = 0xBEFA4FA4;
	}

	ctx->is224 = is224;
	}

	void sha256_process( sha256_context *ctx, const unsigned char data[64] )
	{
	uint32_t temp1, temp2, W[64];
	uint32_t A, B, C, D, E, F, G, H;

	GET_UINT32_BE( W[ 0], data, 0 );
	GET_UINT32_BE( W[ 1], data, 4 );
	GET_UINT32_BE( W[ 2], data, 8 );
	GET_UINT32_BE( W[ 3], data, 12 );
	GET_UINT32_BE( W[ 4], data, 16 );
	GET_UINT32_BE( W[ 5], data, 20 );
	GET_UINT32_BE( W[ 6], data, 24 );
	GET_UINT32_BE( W[ 7], data, 28 );
	GET_UINT32_BE( W[ 8], data, 32 );
	GET_UINT32_BE( W[ 9], data, 36 );
	GET_UINT32_BE( W[10], data, 40 );
	GET_UINT32_BE( W[11], data, 44 );
	GET_UINT32_BE( W[12], data, 48 );
	GET_UINT32_BE( W[13], data, 52 );
	GET_UINT32_BE( W[14], data, 56 );
	GET_UINT32_BE( W[15], data, 60 );

	#define SHR(x,n) ((x & 0xFFFFFFFF) >> n)
	#define ROTR(x,n) (SHR(x,n) \| (x << (32 - n)))

	#define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^ SHR(x, 3))
	#define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^ SHR(x,10))

	#define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
	#define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

	#define F0(x,y,z) ((x & y) \| (z & (x \| y)))
	#define F1(x,y,z) (z ^ (x & (y ^ z)))

	#define R(t) \
	( \
	W[t] = S1(W[t - 2]) + W[t - 7] + \
	S0(W[t - 15]) + W[t - 16] \
	)

	#define P(a,b,c,d,e,f,g,h,x,K) \
	{ \
	temp1 = h + S3(e) + F1(e,f,g) + K + x; \
	temp2 = S2(a) + F0(a,b,c); \
	d += temp1; h = temp1 + temp2; \
	}

	A = ctx->state[0];
	B = ctx->state[1];
	C = ctx->state[2];
	D = ctx->state[3];
	E = ctx->state[4];
	F = ctx->state[5];
	G = ctx->state[6];
	H = ctx->state[7];

	P( A, B, C, D, E, F, G, H, W[ 0], 0x428A2F98 );
	P( H, A, B, C, D, E, F, G, W[ 1], 0x71374491 );
	P( G, H, A, B, C, D, E, F, W[ 2], 0xB5C0FBCF );
	P( F, G, H, A, B, C, D, E, W[ 3], 0xE9B5DBA5 );
	P( E, F, G, H, A, B, C, D, W[ 4], 0x3956C25B );
	P( D, E, F, G, H, A, B, C, W[ 5], 0x59F111F1 );
	P( C, D, E, F, G, H, A, B, W[ 6], 0x923F82A4 );
	P( B, C, D, E, F, G, H, A, W[ 7], 0xAB1C5ED5 );
	P( A, B, C, D, E, F, G, H, W[ 8], 0xD807AA98 );
	P( H, A, B, C, D, E, F, G, W[ 9], 0x12835B01 );
	P( G, H, A, B, C, D, E, F, W[10], 0x243185BE );
	P( F, G, H, A, B, C, D, E, W[11], 0x550C7DC3 );
	P( E, F, G, H, A, B, C, D, W[12], 0x72BE5D74 );
	P( D, E, F, G, H, A, B, C, W[13], 0x80DEB1FE );
	P( C, D, E, F, G, H, A, B, W[14], 0x9BDC06A7 );
	P( B, C, D, E, F, G, H, A, W[15], 0xC19BF174 );
	P( A, B, C, D, E, F, G, H, R(16), 0xE49B69C1 );
	P( H, A, B, C, D, E, F, G, R(17), 0xEFBE4786 );
	P( G, H, A, B, C, D, E, F, R(18), 0x0FC19DC6 );
	P( F, G, H, A, B, C, D, E, R(19), 0x240CA1CC );
	P( E, F, G, H, A, B, C, D, R(20), 0x2DE92C6F );
	P( D, E, F, G, H, A, B, C, R(21), 0x4A7484AA );
	P( C, D, E, F, G, H, A, B, R(22), 0x5CB0A9DC );
	P( B, C, D, E, F, G, H, A, R(23), 0x76F988DA );
	P( A, B, C, D, E, F, G, H, R(24), 0x983E5152 );
	P( H, A, B, C, D, E, F, G, R(25), 0xA831C66D );
	P( G, H, A, B, C, D, E, F, R(26), 0xB00327C8 );
	P( F, G, H, A, B, C, D, E, R(27), 0xBF597FC7 );
	P( E, F, G, H, A, B, C, D, R(28), 0xC6E00BF3 );
	P( D, E, F, G, H, A, B, C, R(29), 0xD5A79147 );
	P( C, D, E, F, G, H, A, B, R(30), 0x06CA6351 );
	P( B, C, D, E, F, G, H, A, R(31), 0x14292967 );
	P( A, B, C, D, E, F, G, H, R(32), 0x27B70A85 );
	P( H, A, B, C, D, E, F, G, R(33), 0x2E1B2138 );
	P( G, H, A, B, C, D, E, F, R(34), 0x4D2C6DFC );
	P( F, G, H, A, B, C, D, E, R(35), 0x53380D13 );
	P( E, F, G, H, A, B, C, D, R(36), 0x650A7354 );
	P( D, E, F, G, H, A, B, C, R(37), 0x766A0ABB );
	P( C, D, E, F, G, H, A, B, R(38), 0x81C2C92E );
	P( B, C, D, E, F, G, H, A, R(39), 0x92722C85 );
	P( A, B, C, D, E, F, G, H, R(40), 0xA2BFE8A1 );
	P( H, A, B, C, D, E, F, G, R(41), 0xA81A664B );
	P( G, H, A, B, C, D, E, F, R(42), 0xC24B8B70 );
	P( F, G, H, A, B, C, D, E, R(43), 0xC76C51A3 );
	P( E, F, G, H, A, B, C, D, R(44), 0xD192E819 );
	P( D, E, F, G, H, A, B, C, R(45), 0xD6990624 );
	P( C, D, E, F, G, H, A, B, R(46), 0xF40E3585 );
	P( B, C, D, E, F, G, H, A, R(47), 0x106AA070 );
	P( A, B, C, D, E, F, G, H, R(48), 0x19A4C116 );
	P( H, A, B, C, D, E, F, G, R(49), 0x1E376C08 );
	P( G, H, A, B, C, D, E, F, R(50), 0x2748774C );
	P( F, G, H, A, B, C, D, E, R(51), 0x34B0BCB5 );
	P( E, F, G, H, A, B, C, D, R(52), 0x391C0CB3 );
	P( D, E, F, G, H, A, B, C, R(53), 0x4ED8AA4A );
	P( C, D, E, F, G, H, A, B, R(54), 0x5B9CCA4F );
	P( B, C, D, E, F, G, H, A, R(55), 0x682E6FF3 );
	P( A, B, C, D, E, F, G, H, R(56), 0x748F82EE );
	P( H, A, B, C, D, E, F, G, R(57), 0x78A5636F );
	P( G, H, A, B, C, D, E, F, R(58), 0x84C87814 );
	P( F, G, H, A, B, C, D, E, R(59), 0x8CC70208 );
	P( E, F, G, H, A, B, C, D, R(60), 0x90BEFFFA );
	P( D, E, F, G, H, A, B, C, R(61), 0xA4506CEB );
	P( C, D, E, F, G, H, A, B, R(62), 0xBEF9A3F7 );
	P( B, C, D, E, F, G, H, A, R(63), 0xC67178F2 );

	ctx->state[0] += A;
	ctx->state[1] += B;
	ctx->state[2] += C;
	ctx->state[3] += D;
	ctx->state[4] += E;
	ctx->state[5] += F;
	ctx->state[6] += G;
	ctx->state[7] += H;
	}

	/*
	* SHA-256 process buffer
	*/
	void sha256_update( sha256_context ctx, const unsigned char input,
	size_t ilen )
	{
	size_t fill;
	uint32_t left;

	if( ilen == 0 )
	return;

	left = ctx->total[0] & 0x3F;
	fill = 64 - left;

	ctx->total[0] += (uint32_t) ilen;
	ctx->total[0] &= 0xFFFFFFFF;

	if( ctx->total[0] < (uint32_t) ilen )
	ctx->total[1]++;

	if( left && ilen >= fill )
	{
	memcpy( (void *) (ctx->buffer + left), input, fill );
	sha256_process( ctx, ctx->buffer );
	input += fill;
	ilen -= fill;
	left = 0;
	}

	while( ilen >= 64 )
	{
	sha256_process( ctx, input );
	input += 64;
	ilen -= 64;
	}

	if( ilen > 0 )
	memcpy( (void *) (ctx->buffer + left), input, ilen );
	}

	static const unsigned char sha256_padding[64] =
	{
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	};

	/*
	* SHA-256 final digest
	*/
	void sha256_finish( sha256_context *ctx, unsigned char output[32] )
	{
	uint32_t last, padn;
	uint32_t high, low;
	unsigned char msglen[8];

	high = ( ctx->total[0] >> 29 )
	\| ( ctx->total[1] << 3 );
	low = ( ctx->total[0] << 3 );

	PUT_UINT32_BE( high, msglen, 0 );
	PUT_UINT32_BE( low, msglen, 4 );

	last = ctx->total[0] & 0x3F;
	padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );

	sha256_update( ctx, sha256_padding, padn );
	sha256_update( ctx, msglen, 8 );

	PUT_UINT32_BE( ctx->state[0], output, 0 );
	PUT_UINT32_BE( ctx->state[1], output, 4 );
	PUT_UINT32_BE( ctx->state[2], output, 8 );
	PUT_UINT32_BE( ctx->state[3], output, 12 );
	PUT_UINT32_BE( ctx->state[4], output, 16 );
	PUT_UINT32_BE( ctx->state[5], output, 20 );
	PUT_UINT32_BE( ctx->state[6], output, 24 );

	if( ctx->is224 == 0 )
	PUT_UINT32_BE( ctx->state[7], output, 28 );
	}

	#endif /* !POLARSSL_SHA256_ALT */

	/*
	* output = SHA-256( input buffer )
	*/
	void sha256( const unsigned char *input, size_t ilen,
	unsigned char output[32], int is224 )
	{
	sha256_context ctx;

	sha256_init( &ctx );
	sha256_starts( &ctx, is224 );
	sha256_update( &ctx, input, ilen );
	sha256_finish( &ctx, output );
	sha256_free( &ctx );
	}

	#if defined(POLARSSL_FS_IO)
	/*
	* output = SHA-256( file contents )
	*/
	int sha256_file( const char *path, unsigned char output[32], int is224 )
	{
	FILE *f;
	size_t n;
	sha256_context ctx;
	unsigned char buf[1024];

	if( ( f = fopen( path, "rb" ) ) == NULL )
	return( POLARSSL_ERR_SHA256_FILE_IO_ERROR );

	sha256_init( &ctx );
	sha256_starts( &ctx, is224 );

	while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
	sha256_update( &ctx, buf, n );

	sha256_finish( &ctx, output );
	sha256_free( &ctx );

	if( ferror( f ) != 0 )
	{
	fclose( f );
	return( POLARSSL_ERR_SHA256_FILE_IO_ERROR );
	}

	fclose( f );
	return( 0 );
	}
	#endif /* POLARSSL_FS_IO */

	/*
	* SHA-256 HMAC context setup
	*/
	void sha256_hmac_starts( sha256_context ctx, const unsigned char key,
	size_t keylen, int is224 )
	{
	size_t i;
	unsigned char sum[32];

	if( keylen > 64 )
	{
	sha256( key, keylen, sum, is224 );
	keylen = ( is224 ) ? 28 : 32;
	key = sum;
	}

	memset( ctx->ipad, 0x36, 64 );
	memset( ctx->opad, 0x5C, 64 );

	for( i = 0; i < keylen; i++ )
	{
	ctx->ipad[i] = (unsigned char)( ctx->ipad[i] ^ key[i] );
	ctx->opad[i] = (unsigned char)( ctx->opad[i] ^ key[i] );
	}

	sha256_starts( ctx, is224 );
	sha256_update( ctx, ctx->ipad, 64 );

	polarssl_zeroize( sum, sizeof( sum ) );
	}

	/*
	* SHA-256 HMAC process buffer
	*/
	void sha256_hmac_update( sha256_context ctx, const unsigned char input,
	size_t ilen )
	{
	sha256_update( ctx, input, ilen );
	}

	/*
	* SHA-256 HMAC final digest
	*/
	void sha256_hmac_finish( sha256_context *ctx, unsigned char output[32] )
	{
	int is224, hlen;
	unsigned char tmpbuf[32];

	is224 = ctx->is224;
	hlen = ( is224 == 0 ) ? 32 : 28;

	sha256_finish( ctx, tmpbuf );
	sha256_starts( ctx, is224 );
	sha256_update( ctx, ctx->opad, 64 );
	sha256_update( ctx, tmpbuf, hlen );
	sha256_finish( ctx, output );

	polarssl_zeroize( tmpbuf, sizeof( tmpbuf ) );
	}

	/*
	* SHA-256 HMAC context reset
	*/
	void sha256_hmac_reset( sha256_context *ctx )
	{
	sha256_starts( ctx, ctx->is224 );
	sha256_update( ctx, ctx->ipad, 64 );
	}

	/*
	* output = HMAC-SHA-256( hmac key, input buffer )
	*/
	void sha256_hmac( const unsigned char *key, size_t keylen,
	const unsigned char *input, size_t ilen,
	unsigned char output[32], int is224 )
	{
	sha256_context ctx;

	sha256_init( &ctx );
	sha256_hmac_starts( &ctx, key, keylen, is224 );
	sha256_hmac_update( &ctx, input, ilen );
	sha256_hmac_finish( &ctx, output );
	sha256_free( &ctx );
	}

	#if defined(POLARSSL_SELF_TEST)
	/*
	* FIPS-180-2 test vectors
	*/
	static unsigned char sha256_test_buf[3][57] =
	{
	{ "abc" },
	{ "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" },
	{ "" }
	};

	static const int sha256_test_buflen[3] =
	{
	3, 56, 1000
	};

	static const unsigned char sha256_test_sum[6][32] =
	{
	/*
	* SHA-224 test vectors
	*/
	{ 0x23, 0x09, 0x7D, 0x22, 0x34, 0x05, 0xD8, 0x22,
	0x86, 0x42, 0xA4, 0x77, 0xBD, 0xA2, 0x55, 0xB3,
	0x2A, 0xAD, 0xBC, 0xE4, 0xBD, 0xA0, 0xB3, 0xF7,
	0xE3, 0x6C, 0x9D, 0xA7 },
	{ 0x75, 0x38, 0x8B, 0x16, 0x51, 0x27, 0x76, 0xCC,
	0x5D, 0xBA, 0x5D, 0xA1, 0xFD, 0x89, 0x01, 0x50,
	0xB0, 0xC6, 0x45, 0x5C, 0xB4, 0xF5, 0x8B, 0x19,
	0x52, 0x52, 0x25, 0x25 },
	{ 0x20, 0x79, 0x46, 0x55, 0x98, 0x0C, 0x91, 0xD8,
	0xBB, 0xB4, 0xC1, 0xEA, 0x97, 0x61, 0x8A, 0x4B,
	0xF0, 0x3F, 0x42, 0x58, 0x19, 0x48, 0xB2, 0xEE,
	0x4E, 0xE7, 0xAD, 0x67 },

	/*
	* SHA-256 test vectors
	*/
	{ 0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA,
	0x41, 0x41, 0x40, 0xDE, 0x5D, 0xAE, 0x22, 0x23,
	0xB0, 0x03, 0x61, 0xA3, 0x96, 0x17, 0x7A, 0x9C,
	0xB4, 0x10, 0xFF, 0x61, 0xF2, 0x00, 0x15, 0xAD },
	{ 0x24, 0x8D, 0x6A, 0x61, 0xD2, 0x06, 0x38, 0xB8,
	0xE5, 0xC0, 0x26, 0x93, 0x0C, 0x3E, 0x60, 0x39,
	0xA3, 0x3C, 0xE4, 0x59, 0x64, 0xFF, 0x21, 0x67,
	0xF6, 0xEC, 0xED, 0xD4, 0x19, 0xDB, 0x06, 0xC1 },
	{ 0xCD, 0xC7, 0x6E, 0x5C, 0x99, 0x14, 0xFB, 0x92,
	0x81, 0xA1, 0xC7, 0xE2, 0x84, 0xD7, 0x3E, 0x67,
	0xF1, 0x80, 0x9A, 0x48, 0xA4, 0x97, 0x20, 0x0E,
	0x04, 0x6D, 0x39, 0xCC, 0xC7, 0x11, 0x2C, 0xD0 }
	};

	/*
	* RFC 4231 test vectors
	*/
	static unsigned char sha256_hmac_test_key[7][26] =
	{
	{ "\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B\x0B"
	"\x0B\x0B\x0B\x0B" },
	{ "Jefe" },
	{ "\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA\xAA"
	"\xAA\xAA\xAA\xAA" },
	{ "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\x10"
	"\x11\x12\x13\x14\x15\x16\x17\x18\x19" },
	{ "\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C"
	"\x0C\x0C\x0C\x0C" },
	{ "" }, /* 0xAA 131 times */
	{ "" }
	};

	static const int sha256_hmac_test_keylen[7] =
	{
	20, 4, 20, 25, 20, 131, 131
	};

	static unsigned char sha256_hmac_test_buf[7][153] =
	{
	{ "Hi There" },
	{ "what do ya want for nothing?" },
	{ "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
	"\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
	"\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
	"\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
	"\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD" },
	{ "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD" },
	{ "Test With Truncation" },
	{ "Test Using Larger Than Block-Size Key - Hash Key First" },
	{ "This is a test using a larger than block-size key "
	"and a larger than block-size data. The key needs to "
	"be hashed before being used by the HMAC algorithm." }
	};

	static const int sha256_hmac_test_buflen[7] =
	{
	8, 28, 50, 50, 20, 54, 152
	};

	static const unsigned char sha256_hmac_test_sum[14][32] =
	{
	/*
	* HMAC-SHA-224 test vectors
	*/
	{ 0x89, 0x6F, 0xB1, 0x12, 0x8A, 0xBB, 0xDF, 0x19,
	0x68, 0x32, 0x10, 0x7C, 0xD4, 0x9D, 0xF3, 0x3F,
	0x47, 0xB4, 0xB1, 0x16, 0x99, 0x12, 0xBA, 0x4F,
	0x53, 0x68, 0x4B, 0x22 },
	{ 0xA3, 0x0E, 0x01, 0x09, 0x8B, 0xC6, 0xDB, 0xBF,
	0x45, 0x69, 0x0F, 0x3A, 0x7E, 0x9E, 0x6D, 0x0F,
	0x8B, 0xBE, 0xA2, 0xA3, 0x9E, 0x61, 0x48, 0x00,
	0x8F, 0xD0, 0x5E, 0x44 },
	{ 0x7F, 0xB3, 0xCB, 0x35, 0x88, 0xC6, 0xC1, 0xF6,
	0xFF, 0xA9, 0x69, 0x4D, 0x7D, 0x6A, 0xD2, 0x64,
	0x93, 0x65, 0xB0, 0xC1, 0xF6, 0x5D, 0x69, 0xD1,
	0xEC, 0x83, 0x33, 0xEA },
	{ 0x6C, 0x11, 0x50, 0x68, 0x74, 0x01, 0x3C, 0xAC,
	0x6A, 0x2A, 0xBC, 0x1B, 0xB3, 0x82, 0x62, 0x7C,
	0xEC, 0x6A, 0x90, 0xD8, 0x6E, 0xFC, 0x01, 0x2D,
	0xE7, 0xAF, 0xEC, 0x5A },
	{ 0x0E, 0x2A, 0xEA, 0x68, 0xA9, 0x0C, 0x8D, 0x37,
	0xC9, 0x88, 0xBC, 0xDB, 0x9F, 0xCA, 0x6F, 0xA8 },
	{ 0x95, 0xE9, 0xA0, 0xDB, 0x96, 0x20, 0x95, 0xAD,
	0xAE, 0xBE, 0x9B, 0x2D, 0x6F, 0x0D, 0xBC, 0xE2,
	0xD4, 0x99, 0xF1, 0x12, 0xF2, 0xD2, 0xB7, 0x27,
	0x3F, 0xA6, 0x87, 0x0E },
	{ 0x3A, 0x85, 0x41, 0x66, 0xAC, 0x5D, 0x9F, 0x02,
	0x3F, 0x54, 0xD5, 0x17, 0xD0, 0xB3, 0x9D, 0xBD,
	0x94, 0x67, 0x70, 0xDB, 0x9C, 0x2B, 0x95, 0xC9,
	0xF6, 0xF5, 0x65, 0xD1 },

	/*
	* HMAC-SHA-256 test vectors
	*/
	{ 0xB0, 0x34, 0x4C, 0x61, 0xD8, 0xDB, 0x38, 0x53,
	0x5C, 0xA8, 0xAF, 0xCE, 0xAF, 0x0B, 0xF1, 0x2B,
	0x88, 0x1D, 0xC2, 0x00, 0xC9, 0x83, 0x3D, 0xA7,
	0x26, 0xE9, 0x37, 0x6C, 0x2E, 0x32, 0xCF, 0xF7 },
	{ 0x5B, 0xDC, 0xC1, 0x46, 0xBF, 0x60, 0x75, 0x4E,
	0x6A, 0x04, 0x24, 0x26, 0x08, 0x95, 0x75, 0xC7,
	0x5A, 0x00, 0x3F, 0x08, 0x9D, 0x27, 0x39, 0x83,
	0x9D, 0xEC, 0x58, 0xB9, 0x64, 0xEC, 0x38, 0x43 },
	{ 0x77, 0x3E, 0xA9, 0x1E, 0x36, 0x80, 0x0E, 0x46,
	0x85, 0x4D, 0xB8, 0xEB, 0xD0, 0x91, 0x81, 0xA7,
	0x29, 0x59, 0x09, 0x8B, 0x3E, 0xF8, 0xC1, 0x22,
	0xD9, 0x63, 0x55, 0x14, 0xCE, 0xD5, 0x65, 0xFE },
	{ 0x82, 0x55, 0x8A, 0x38, 0x9A, 0x44, 0x3C, 0x0E,
	0xA4, 0xCC, 0x81, 0x98, 0x99, 0xF2, 0x08, 0x3A,
	0x85, 0xF0, 0xFA, 0xA3, 0xE5, 0x78, 0xF8, 0x07,
	0x7A, 0x2E, 0x3F, 0xF4, 0x67, 0x29, 0x66, 0x5B },
	{ 0xA3, 0xB6, 0x16, 0x74, 0x73, 0x10, 0x0E, 0xE0,
	0x6E, 0x0C, 0x79, 0x6C, 0x29, 0x55, 0x55, 0x2B },
	{ 0x60, 0xE4, 0x31, 0x59, 0x1E, 0xE0, 0xB6, 0x7F,
	0x0D, 0x8A, 0x26, 0xAA, 0xCB, 0xF5, 0xB7, 0x7F,
	0x8E, 0x0B, 0xC6, 0x21, 0x37, 0x28, 0xC5, 0x14,
	0x05, 0x46, 0x04, 0x0F, 0x0E, 0xE3, 0x7F, 0x54 },
	{ 0x9B, 0x09, 0xFF, 0xA7, 0x1B, 0x94, 0x2F, 0xCB,
	0x27, 0x63, 0x5F, 0xBC, 0xD5, 0xB0, 0xE9, 0x44,
	0xBF, 0xDC, 0x63, 0x64, 0x4F, 0x07, 0x13, 0x93,
	0x8A, 0x7F, 0x51, 0x53, 0x5C, 0x3A, 0x35, 0xE2 }
	};

	/*
	* Checkup routine
	*/
	int sha256_self_test( int verbose )
	{
	int i, j, k, buflen, ret = 0;
	unsigned char buf[1024];
	unsigned char sha256sum[32];
	sha256_context ctx;

	sha256_init( &ctx );

	for( i = 0; i < 6; i++ )
	{
	j = i % 3;
	k = i < 3;

	if( verbose != 0 )
	polarssl_printf( " SHA-%d test #%d: ", 256 - k * 32, j + 1 );

	sha256_starts( &ctx, k );

	if( j == 2 )
	{
	memset( buf, 'a', buflen = 1000 );

	for( j = 0; j < 1000; j++ )
	sha256_update( &ctx, buf, buflen );
	}
	else
	sha256_update( &ctx, sha256_test_buf[j],
	sha256_test_buflen[j] );

	sha256_finish( &ctx, sha256sum );

	if( memcmp( sha256sum, sha256_test_sum[i], 32 - k * 4 ) != 0 )
	{
	if( verbose != 0 )
	polarssl_printf( "failed\n" );

	ret = 1;
	goto exit;
	}

	if( verbose != 0 )
	polarssl_printf( "passed\n" );
	}

	if( verbose != 0 )
	polarssl_printf( "\n" );

	for( i = 0; i < 14; i++ )
	{
	j = i % 7;
	k = i < 7;

	if( verbose != 0 )
	polarssl_printf( " HMAC-SHA-%d test #%d: ", 256 - k * 32, j + 1 );

	if( j == 5 \|\| j == 6 )
	{
	memset( buf, '\xAA', buflen = 131 );
	sha256_hmac_starts( &ctx, buf, buflen, k );
	}
	else
	sha256_hmac_starts( &ctx, sha256_hmac_test_key[j],
	sha256_hmac_test_keylen[j], k );

	sha256_hmac_update( &ctx, sha256_hmac_test_buf[j],
	sha256_hmac_test_buflen[j] );

	sha256_hmac_finish( &ctx, sha256sum );

	buflen = ( j == 4 ) ? 16 : 32 - k * 4;

	if( memcmp( sha256sum, sha256_hmac_test_sum[i], buflen ) != 0 )
	{
	if( verbose != 0 )
	polarssl_printf( "failed\n" );

	ret = 1;
	goto exit;
	}

	if( verbose != 0 )
	polarssl_printf( "passed\n" );
	}

	if( verbose != 0 )
	polarssl_printf( "\n" );

	exit:
	sha256_free( &ctx );

	return( ret );
	}

	#endif /* POLARSSL_SELF_TEST */

	#endif /* POLARSSL_SHA256_C */