text: /*
   *  NIST SP800-38D compliant GCM implementation
   *
   *  Copyright The Mbed TLS Contributors
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  /*
   * http://csrc.nist.gov/publications/nistpubs/800-38D/SP-800-38D.pdf
   *
   * See also:
   * [MGV] http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/proposedmodes/gcm/gcm-revised-spec.pdf
   *
   * We use the algorithm described as Shoup's method with 4-bit tables in
   * [MGV] 4.1, pp. 12-13, to enhance speed without using too much memory.
   */
  
  #include "common.h"
  
  #if defined(MBEDTLS_GCM_C)
  
  #include "gcm.h"
  #include "platform_util.h"
  #include "error.h"
  
  #include <string.h>
  
  #if defined(MBEDTLS_AESNI_C)
  #include "aesni.h"
  #endif
  
  #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
  #include "mbed_aes.h"
  #include "mbed_platform.h"
  #if !defined(MBEDTLS_PLATFORM_C)
  #include <stdio.h>
  #define mbedtls_printf printf
  #endif /* MBEDTLS_PLATFORM_C */
  #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
  
  #if !defined(MBEDTLS_GCM_ALT)
  
  /* Parameter validation macros */
  #define GCM_VALIDATE_RET( cond ) \
      MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_GCM_BAD_INPUT )
  #define GCM_VALIDATE( cond ) \
      MBEDTLS_INTERNAL_VALIDATE( cond )
  
  /*
   * 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
  
  /*
   * Initialize a context
   */
  void mbedtls_gcm_init( mbedtls_gcm_context *ctx )
  {
      GCM_VALIDATE( ctx != NULL );
      memset( ctx, 0, sizeof( mbedtls_gcm_context ) );
  }
  
  /*
   * Precompute small multiples of H, that is set
   *      HH[i] || HL[i] = H times i,
   * where i is seen as a field element as in [MGV], ie high-order bits
   * correspond to low powers of P. The result is stored in the same way, that
   * is the high-order bit of HH corresponds to P^0 and the low-order bit of HL
   * corresponds to P^127.
   */
  static int gcm_gen_table( mbedtls_gcm_context *ctx )
  {
      int ret, i, j;
      uint64_t hi, lo;
      uint64_t vl, vh;
      unsigned char h[16];
      size_t olen = 0;
  
      memset( h, 0, 16 );
      if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, h, 16, h, &olen ) ) != 0 )
          return( ret );
  
      /* pack h as two 64-bits ints, big-endian */
      GET_UINT32_BE( hi, h,  0  );
      GET_UINT32_BE( lo, h,  4  );
      vh = (uint64_t) hi << 32 | lo;
  
      GET_UINT32_BE( hi, h,  8  );
      GET_UINT32_BE( lo, h,  12 );
      vl = (uint64_t) hi << 32 | lo;
  
      /* 8 = 1000 corresponds to 1 in GF(2^128) */
      ctx->HL[8] = vl;
      ctx->HH[8] = vh;
  
  #if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
      /* With CLMUL support, we need only h, not the rest of the table */
      if( mbedtls_aesni_has_support( MBEDTLS_AESNI_CLMUL ) )
          return( 0 );
  #endif
  
      /* 0 corresponds to 0 in GF(2^128) */
      ctx->HH[0] = 0;
      ctx->HL[0] = 0;
  
      for( i = 4; i > 0; i >>= 1 )
      {
          uint32_t T = ( vl & 1 ) * 0xe1000000U;
          vl  = ( vh << 63 ) | ( vl >> 1 );
          vh  = ( vh >> 1 ) ^ ( (uint64_t) T << 32);
  
          ctx->HL[i] = vl;
          ctx->HH[i] = vh;
      }
  
      for( i = 2; i <= 8; i *= 2 )
      {
          uint64_t *HiL = ctx->HL + i, *HiH = ctx->HH + i;
          vh = *HiH;
          vl = *HiL;
          for( j = 1; j < i; j++ )
          {
              HiH[j] = vh ^ ctx->HH[j];
              HiL[j] = vl ^ ctx->HL[j];
          }
      }
  
      return( 0 );
  }
  
  int mbedtls_gcm_setkey( mbedtls_gcm_context *ctx,
                          mbedtls_cipher_id_t cipher,
                          const unsigned char *key,
                          unsigned int keybits )
  {
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
      const mbedtls_cipher_info_t *cipher_info;
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( key != NULL );
      GCM_VALIDATE_RET( keybits == 128 || keybits == 192 || keybits == 256 );
  
      cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
                                                     MBEDTLS_MODE_ECB );
      if( cipher_info == NULL )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      if( cipher_info->block_size != 16 )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      mbedtls_cipher_free( &ctx->cipher_ctx );
  
      if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
          return( ret );
  
      if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
                                 MBEDTLS_ENCRYPT ) ) != 0 )
      {
          return( ret );
      }
  
      if( ( ret = gcm_gen_table( ctx ) ) != 0 )
          return( ret );
  
      return( 0 );
  }
  
  /*
   * Shoup's method for multiplication use this table with
   *      last4[x] = x times P^128
   * where x and last4[x] are seen as elements of GF(2^128) as in [MGV]
   */
  static const uint64_t last4[16] =
  {
      0x0000, 0x1c20, 0x3840, 0x2460,
      0x7080, 0x6ca0, 0x48c0, 0x54e0,
      0xe100, 0xfd20, 0xd940, 0xc560,
      0x9180, 0x8da0, 0xa9c0, 0xb5e0
  };
  
  /*
   * Sets output to x times H using the precomputed tables.
   * x and output are seen as elements of GF(2^128) as in [MGV].
   */
  static void gcm_mult( mbedtls_gcm_context *ctx, const unsigned char x[16],
                        unsigned char output[16] )
  {
      int i = 0;
      unsigned char lo, hi, rem;
      uint64_t zh, zl;
  
  #if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
      if( mbedtls_aesni_has_support( MBEDTLS_AESNI_CLMUL ) ) {
          unsigned char h[16];
  
          PUT_UINT32_BE( ctx->HH[8] >> 32, h,  0 );
          PUT_UINT32_BE( ctx->HH[8],       h,  4 );
          PUT_UINT32_BE( ctx->HL[8] >> 32, h,  8 );
          PUT_UINT32_BE( ctx->HL[8],       h, 12 );
  
          mbedtls_aesni_gcm_mult( output, x, h );
          return;
      }
  #endif /* MBEDTLS_AESNI_C && MBEDTLS_HAVE_X86_64 */
  
      lo = x[15] & 0xf;
  
      zh = ctx->HH[lo];
      zl = ctx->HL[lo];
  
      for( i = 15; i >= 0; i-- )
      {
          lo = x[i] & 0xf;
          hi = ( x[i] >> 4 ) & 0xf;
  
          if( i != 15 )
          {
              rem = (unsigned char) zl & 0xf;
              zl = ( zh << 60 ) | ( zl >> 4 );
              zh = ( zh >> 4 );
              zh ^= (uint64_t) last4[rem] << 48;
              zh ^= ctx->HH[lo];
              zl ^= ctx->HL[lo];
  
          }
  
          rem = (unsigned char) zl & 0xf;
          zl = ( zh << 60 ) | ( zl >> 4 );
          zh = ( zh >> 4 );
          zh ^= (uint64_t) last4[rem] << 48;
          zh ^= ctx->HH[hi];
          zl ^= ctx->HL[hi];
      }
  
      PUT_UINT32_BE( zh >> 32, output, 0 );
      PUT_UINT32_BE( zh, output, 4 );
      PUT_UINT32_BE( zl >> 32, output, 8 );
      PUT_UINT32_BE( zl, output, 12 );
  }
  
  int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
                          int mode,
                          const unsigned char *iv, size_t iv_len )
  {
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
      unsigned char work_buf[16];
      size_t i;
      const unsigned char *p;
      size_t use_len, olen = 0;
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( iv != NULL );
  
      /* IV is are limited to 2^64 bits, so 2^61 bytes */
      /* IV is not allowed to be zero length */
      if( iv_len == 0 || (uint64_t) iv_len >> 61 != 0 )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      memset( ctx->y, 0x00, sizeof(ctx->y) );
      memset( ctx->buf, 0x00, sizeof(ctx->buf) );
  
      ctx->mode = mode;
      ctx->len = 0;
      ctx->add_len = 0;
  
      if( iv_len == 12 )
      {
          memcpy( ctx->y, iv, iv_len );
          ctx->y[15] = 1;
      }
      else
      {
          memset( work_buf, 0x00, 16 );
          PUT_UINT32_BE( iv_len * 8, work_buf, 12 );
  
          p = iv;
          while( iv_len > 0 )
          {
              use_len = ( iv_len < 16 ) ? iv_len : 16;
  
              for( i = 0; i < use_len; i++ )
                  ctx->y[i] ^= p[i];
  
              gcm_mult( ctx, ctx->y, ctx->y );
  
              iv_len -= use_len;
              p += use_len;
          }
  
          for( i = 0; i < 16; i++ )
              ctx->y[i] ^= work_buf[i];
  
          gcm_mult( ctx, ctx->y, ctx->y );
      }
  
      if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16,
                                         ctx->base_ectr, &olen ) ) != 0 )
      {
          return( ret );
      }
  
      return( 0 );
  }
  
  
  int mbedtls_gcm_update_ad( mbedtls_gcm_context *ctx,
                             const unsigned char *add, size_t add_len )
  {
      const unsigned char *p;
      size_t use_len, i;
  
      GCM_VALIDATE_RET( add_len == 0 || add != NULL );
  
      /* IV is are limited to 2^64 bits, so 2^61 bytes */
      if( (uint64_t) add_len >> 61 != 0 )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      /* Calling update_ad multiple times is not yet supported */
      if( ctx->add_len != 0 )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      ctx->add_len = add_len;
      p = add;
      while( add_len > 0 )
      {
          use_len = ( add_len < 16 ) ? add_len : 16;
  
          for( i = 0; i < use_len; i++ )
              ctx->buf[i] ^= p[i];
  
          gcm_mult( ctx, ctx->buf, ctx->buf );
  
          add_len -= use_len;
          p += use_len;
      }
  
      return( 0 );
  }
  
  /* Increment the counter. */
  static void gcm_incr( unsigned char y[16] )
  {
      size_t i;
      for( i = 16; i > 12; i-- )
          if( ++y[i - 1] != 0 )
              break;
  }
  
  /* Calculate and apply the encryption mask. Process use_len bytes of data,
   * starting at position offset in the mask block. */
  static int gcm_mask( mbedtls_gcm_context *ctx,
                       unsigned char ectr[16],
                       size_t offset, size_t use_len,
                       const unsigned char *input,
                       unsigned char *output )
  {
      size_t i;
      size_t olen = 0;
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
  
      if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ectr,
                                         &olen ) ) != 0 )
      {
          mbedtls_platform_zeroize( ectr, 16 );
          return( ret );
      }
  
      for( i = 0; i < use_len; i++ )
      {
          if( ctx->mode == MBEDTLS_GCM_DECRYPT )
              ctx->buf[offset + i] ^= input[i];
          output[i] = ectr[offset + i] ^ input[i];
          if( ctx->mode == MBEDTLS_GCM_ENCRYPT )
              ctx->buf[offset + i] ^= output[i];
      }
      return( 0 );
  }
  
  int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
                          const unsigned char *input, size_t input_length,
                          unsigned char *output, size_t output_size,
                          size_t *output_length )
  {
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
      const unsigned char *p = input;
      unsigned char *out_p = output;
      size_t offset;
      unsigned char ectr[16];
  
      if( output_size < input_length )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
      GCM_VALIDATE_RET( output_length != NULL );
      *output_length = input_length;
  
      /* Exit early if input_length==0 so that we don't do any pointer arithmetic
       * on a potentially null pointer. */
      if( input_length == 0 )
          return( 0 );
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( input != NULL );
      GCM_VALIDATE_RET( output != NULL );
  
      if( output > input && (size_t) ( output - input ) < input_length )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      /* Total length is restricted to 2^39 - 256 bits, ie 2^36 - 2^5 bytes
       * Also check for possible overflow */
      if( ctx->len + input_length < ctx->len ||
          (uint64_t) ctx->len + input_length > 0xFFFFFFFE0ull )
      {
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
      }
  
      offset = ctx->len % 16;
      if( offset != 0 )
      {
          size_t use_len = 16 - offset;
          if( use_len > input_length )
              use_len = input_length;
  
          if( ( ret = gcm_mask( ctx, ectr, offset, use_len, p, out_p ) ) != 0 )
              return( ret );
  
          if( offset + use_len == 16 )
              gcm_mult( ctx, ctx->buf, ctx->buf );
  
          ctx->len += use_len;
          input_length -= use_len;
          p += use_len;
          out_p += use_len;
      }
  
      ctx->len += input_length;
  
      while( input_length >= 16 )
      {
          gcm_incr( ctx->y );
          if( ( ret = gcm_mask( ctx, ectr, 0, 16, p, out_p ) ) != 0 )
              return( ret );
  
          gcm_mult( ctx, ctx->buf, ctx->buf );
  
          input_length -= 16;
          p += 16;
          out_p += 16;
      }
  
      if( input_length > 0 )
      {
          gcm_incr( ctx->y );
          if( ( ret = gcm_mask( ctx, ectr, 0, input_length, p, out_p ) ) != 0 )
              return( ret );
      }
  
      mbedtls_platform_zeroize( ectr, sizeof( ectr ) );
      return( 0 );
  }
  
  int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
                          unsigned char *output, size_t output_size,
                          unsigned char *tag, size_t tag_len )
  {
      unsigned char work_buf[16];
      size_t i;
      uint64_t orig_len;
      uint64_t orig_add_len;
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( tag != NULL );
  
      /* We never pass any output in finish(). The output parameter exists only
       * for the sake of alternative implementations. */
      (void) output;
      (void) output_size;
  
      orig_len = ctx->len * 8;
      orig_add_len = ctx->add_len * 8;
  
      if( tag_len > 16 || tag_len < 4 )
          return( MBEDTLS_ERR_GCM_BAD_INPUT );
  
      if( ctx->len % 16 != 0 )
          gcm_mult( ctx, ctx->buf, ctx->buf );
  
      memcpy( tag, ctx->base_ectr, tag_len );
  
      if( orig_len || orig_add_len )
      {
          memset( work_buf, 0x00, 16 );
  
          PUT_UINT32_BE( ( orig_add_len >> 32 ), work_buf, 0  );
          PUT_UINT32_BE( ( orig_add_len       ), work_buf, 4  );
          PUT_UINT32_BE( ( orig_len     >> 32 ), work_buf, 8  );
          PUT_UINT32_BE( ( orig_len           ), work_buf, 12 );
  
          for( i = 0; i < 16; i++ )
              ctx->buf[i] ^= work_buf[i];
  
          gcm_mult( ctx, ctx->buf, ctx->buf );
  
          for( i = 0; i < tag_len; i++ )
              tag[i] ^= ctx->buf[i];
      }
  
      return( 0 );
  }
  
  int mbedtls_gcm_crypt_and_tag( mbedtls_gcm_context *ctx,
                         int mode,
                         size_t length,
                         const unsigned char *iv,
                         size_t iv_len,
                         const unsigned char *add,
                         size_t add_len,
                         const unsigned char *input,
                         unsigned char *output,
                         size_t tag_len,
                         unsigned char *tag )
  {
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
      size_t olen;
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( iv != NULL );
      GCM_VALIDATE_RET( add_len == 0 || add != NULL );
      GCM_VALIDATE_RET( length == 0 || input != NULL );
      GCM_VALIDATE_RET( length == 0 || output != NULL );
      GCM_VALIDATE_RET( tag != NULL );
  
      if( ( ret = mbedtls_gcm_starts( ctx, mode, iv, iv_len ) ) != 0 )
          return( ret );
  
      if( ( ret = mbedtls_gcm_update_ad( ctx, add, add_len ) ) != 0 )
          return( ret );
  
      if( ( ret = mbedtls_gcm_update( ctx, input, length,
                                      output, length, &olen ) ) != 0 )
          return( ret );
  
      if( ( ret = mbedtls_gcm_finish( ctx, NULL, 0, tag, tag_len ) ) != 0 )
          return( ret );
  
      return( 0 );
  }
  
  int mbedtls_gcm_auth_decrypt( mbedtls_gcm_context *ctx,
                        size_t length,
                        const unsigned char *iv,
                        size_t iv_len,
                        const unsigned char *add,
                        size_t add_len,
                        const unsigned char *tag,
                        size_t tag_len,
                        const unsigned char *input,
                        unsigned char *output )
  {
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
      unsigned char check_tag[16];
      size_t i;
      int diff;
  
      GCM_VALIDATE_RET( ctx != NULL );
      GCM_VALIDATE_RET( iv != NULL );
      GCM_VALIDATE_RET( add_len == 0 || add != NULL );
      GCM_VALIDATE_RET( tag != NULL );
      GCM_VALIDATE_RET( length == 0 || input != NULL );
      GCM_VALIDATE_RET( length == 0 || output != NULL );
  
      if( ( ret = mbedtls_gcm_crypt_and_tag( ctx, MBEDTLS_GCM_DECRYPT, length,
                                     iv, iv_len, add, add_len,
                                     input, output, tag_len, check_tag ) ) != 0 )
      {
          return( ret );
      }
  
      /* Check tag in "constant-time" */
      for( diff = 0, i = 0; i < tag_len; i++ )
          diff |= tag[i] ^ check_tag[i];
  
      if( diff != 0 )
      {
          mbedtls_platform_zeroize( output, length );
          return( MBEDTLS_ERR_GCM_AUTH_FAILED );
      }
  
      return( 0 );
  }
  
  void mbedtls_gcm_free( mbedtls_gcm_context *ctx )
  {
      if( ctx == NULL )
          return;
      mbedtls_cipher_free( &ctx->cipher_ctx );
      mbedtls_platform_zeroize( ctx, sizeof( mbedtls_gcm_context ) );
  }
  
  #endif /* !MBEDTLS_GCM_ALT */
  
  #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
  /*
   * AES-GCM test vectors from:
   *
   * http://csrc.nist.gov/groups/STM/cavp/documents/mac/gcmtestvectors.zip
   */
  #define MAX_TESTS   6
  
  static const int key_index_test_data[MAX_TESTS] =
      { 0, 0, 1, 1, 1, 1 };
  
  static const unsigned char key_test_data[MAX_TESTS][32] =
  {
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
        0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08,
        0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
        0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08 },
  };
  
  static const size_t iv_len_test_data[MAX_TESTS] =
      { 12, 12, 12, 12, 8, 60 };
  
  static const int iv_index_test_data[MAX_TESTS] =
      { 0, 0, 1, 1, 1, 2 };
  
  static const unsigned char iv_test_data[MAX_TESTS][64] =
  {
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00 },
      { 0xca, 0xfe, 0xba, 0xbe, 0xfa, 0xce, 0xdb, 0xad,
        0xde, 0xca, 0xf8, 0x88 },
      { 0x93, 0x13, 0x22, 0x5d, 0xf8, 0x84, 0x06, 0xe5,
        0x55, 0x90, 0x9c, 0x5a, 0xff, 0x52, 0x69, 0xaa,
        0x6a, 0x7a, 0x95, 0x38, 0x53, 0x4f, 0x7d, 0xa1,
        0xe4, 0xc3, 0x03, 0xd2, 0xa3, 0x18, 0xa7, 0x28,
        0xc3, 0xc0, 0xc9, 0x51, 0x56, 0x80, 0x95, 0x39,
        0xfc, 0xf0, 0xe2, 0x42, 0x9a, 0x6b, 0x52, 0x54,
        0x16, 0xae, 0xdb, 0xf5, 0xa0, 0xde, 0x6a, 0x57,
        0xa6, 0x37, 0xb3, 0x9b },
  };
  
  static const size_t add_len_test_data[MAX_TESTS] =
      { 0, 0, 0, 20, 20, 20 };
  
  static const int add_index_test_data[MAX_TESTS] =
      { 0, 0, 0, 1, 1, 1 };
  
  static const unsigned char additional_test_data[MAX_TESTS][64] =
  {
      { 0x00 },
      { 0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
        0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
        0xab, 0xad, 0xda, 0xd2 },
  };
  
  static const size_t pt_len_test_data[MAX_TESTS] =
      { 0, 16, 64, 60, 60, 60 };
  
  static const int pt_index_test_data[MAX_TESTS] =
      { 0, 0, 1, 1, 1, 1 };
  
  static const unsigned char pt_test_data[MAX_TESTS][64] =
  {
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0xd9, 0x31, 0x32, 0x25, 0xf8, 0x84, 0x06, 0xe5,
        0xa5, 0x59, 0x09, 0xc5, 0xaf, 0xf5, 0x26, 0x9a,
        0x86, 0xa7, 0xa9, 0x53, 0x15, 0x34, 0xf7, 0xda,
        0x2e, 0x4c, 0x30, 0x3d, 0x8a, 0x31, 0x8a, 0x72,
        0x1c, 0x3c, 0x0c, 0x95, 0x95, 0x68, 0x09, 0x53,
        0x2f, 0xcf, 0x0e, 0x24, 0x49, 0xa6, 0xb5, 0x25,
        0xb1, 0x6a, 0xed, 0xf5, 0xaa, 0x0d, 0xe6, 0x57,
        0xba, 0x63, 0x7b, 0x39, 0x1a, 0xaf, 0xd2, 0x55 },
  };
  
  static const unsigned char ct_test_data[MAX_TESTS * 3][64] =
  {
      { 0x00 },
      { 0x03, 0x88, 0xda, 0xce, 0x60, 0xb6, 0xa3, 0x92,
        0xf3, 0x28, 0xc2, 0xb9, 0x71, 0xb2, 0xfe, 0x78 },
      { 0x42, 0x83, 0x1e, 0xc2, 0x21, 0x77, 0x74, 0x24,
        0x4b, 0x72, 0x21, 0xb7, 0x84, 0xd0, 0xd4, 0x9c,
        0xe3, 0xaa, 0x21, 0x2f, 0x2c, 0x02, 0xa4, 0xe0,
        0x35, 0xc1, 0x7e, 0x23, 0x29, 0xac, 0xa1, 0x2e,
        0x21, 0xd5, 0x14, 0xb2, 0x54, 0x66, 0x93, 0x1c,
        0x7d, 0x8f, 0x6a, 0x5a, 0xac, 0x84, 0xaa, 0x05,
        0x1b, 0xa3, 0x0b, 0x39, 0x6a, 0x0a, 0xac, 0x97,
        0x3d, 0x58, 0xe0, 0x91, 0x47, 0x3f, 0x59, 0x85 },
      { 0x42, 0x83, 0x1e, 0xc2, 0x21, 0x77, 0x74, 0x24,
        0x4b, 0x72, 0x21, 0xb7, 0x84, 0xd0, 0xd4, 0x9c,
        0xe3, 0xaa, 0x21, 0x2f, 0x2c, 0x02, 0xa4, 0xe0,
        0x35, 0xc1, 0x7e, 0x23, 0x29, 0xac, 0xa1, 0x2e,
        0x21, 0xd5, 0x14, 0xb2, 0x54, 0x66, 0x93, 0x1c,
        0x7d, 0x8f, 0x6a, 0x5a, 0xac, 0x84, 0xaa, 0x05,
        0x1b, 0xa3, 0x0b, 0x39, 0x6a, 0x0a, 0xac, 0x97,
        0x3d, 0x58, 0xe0, 0x91 },
      { 0x61, 0x35, 0x3b, 0x4c, 0x28, 0x06, 0x93, 0x4a,
        0x77, 0x7f, 0xf5, 0x1f, 0xa2, 0x2a, 0x47, 0x55,
        0x69, 0x9b, 0x2a, 0x71, 0x4f, 0xcd, 0xc6, 0xf8,
        0x37, 0x66, 0xe5, 0xf9, 0x7b, 0x6c, 0x74, 0x23,
        0x73, 0x80, 0x69, 0x00, 0xe4, 0x9f, 0x24, 0xb2,
        0x2b, 0x09, 0x75, 0x44, 0xd4, 0x89, 0x6b, 0x42,
        0x49, 0x89, 0xb5, 0xe1, 0xeb, 0xac, 0x0f, 0x07,
        0xc2, 0x3f, 0x45, 0x98 },
      { 0x8c, 0xe2, 0x49, 0x98, 0x62, 0x56, 0x15, 0xb6,
        0x03, 0xa0, 0x33, 0xac, 0xa1, 0x3f, 0xb8, 0x94,
        0xbe, 0x91, 0x12, 0xa5, 0xc3, 0xa2, 0x11, 0xa8,
        0xba, 0x26, 0x2a, 0x3c, 0xca, 0x7e, 0x2c, 0xa7,
        0x01, 0xe4, 0xa9, 0xa4, 0xfb, 0xa4, 0x3c, 0x90,
        0xcc, 0xdc, 0xb2, 0x81, 0xd4, 0x8c, 0x7c, 0x6f,
        0xd6, 0x28, 0x75, 0xd2, 0xac, 0xa4, 0x17, 0x03,
        0x4c, 0x34, 0xae, 0xe5 },
      { 0x00 },
      { 0x98, 0xe7, 0x24, 0x7c, 0x07, 0xf0, 0xfe, 0x41,
        0x1c, 0x26, 0x7e, 0x43, 0x84, 0xb0, 0xf6, 0x00 },
      { 0x39, 0x80, 0xca, 0x0b, 0x3c, 0x00, 0xe8, 0x41,
        0xeb, 0x06, 0xfa, 0xc4, 0x87, 0x2a, 0x27, 0x57,
        0x85, 0x9e, 0x1c, 0xea, 0xa6, 0xef, 0xd9, 0x84,
        0x62, 0x85, 0x93, 0xb4, 0x0c, 0xa1, 0xe1, 0x9c,
        0x7d, 0x77, 0x3d, 0x00, 0xc1, 0x44, 0xc5, 0x25,
        0xac, 0x61, 0x9d, 0x18, 0xc8, 0x4a, 0x3f, 0x47,
        0x18, 0xe2, 0x44, 0x8b, 0x2f, 0xe3, 0x24, 0xd9,
        0xcc, 0xda, 0x27, 0x10, 0xac, 0xad, 0xe2, 0x56 },
      { 0x39, 0x80, 0xca, 0x0b, 0x3c, 0x00, 0xe8, 0x41,
        0xeb, 0x06, 0xfa, 0xc4, 0x87, 0x2a, 0x27, 0x57,
        0x85, 0x9e, 0x1c, 0xea, 0xa6, 0xef, 0xd9, 0x84,
        0x62, 0x85, 0x93, 0xb4, 0x0c, 0xa1, 0xe1, 0x9c,
        0x7d, 0x77, 0x3d, 0x00, 0xc1, 0x44, 0xc5, 0x25,
        0xac, 0x61, 0x9d, 0x18, 0xc8, 0x4a, 0x3f, 0x47,
        0x18, 0xe2, 0x44, 0x8b, 0x2f, 0xe3, 0x24, 0xd9,
        0xcc, 0xda, 0x27, 0x10 },
      { 0x0f, 0x10, 0xf5, 0x99, 0xae, 0x14, 0xa1, 0x54,
        0xed, 0x24, 0xb3, 0x6e, 0x25, 0x32, 0x4d, 0xb8,
        0xc5, 0x66, 0x63, 0x2e, 0xf2, 0xbb, 0xb3, 0x4f,
        0x83, 0x47, 0x28, 0x0f, 0xc4, 0x50, 0x70, 0x57,
        0xfd, 0xdc, 0x29, 0xdf, 0x9a, 0x47, 0x1f, 0x75,
        0xc6, 0x65, 0x41, 0xd4, 0xd4, 0xda, 0xd1, 0xc9,
        0xe9, 0x3a, 0x19, 0xa5, 0x8e, 0x8b, 0x47, 0x3f,
        0xa0, 0xf0, 0x62, 0xf7 },
      { 0xd2, 0x7e, 0x88, 0x68, 0x1c, 0xe3, 0x24, 0x3c,
        0x48, 0x30, 0x16, 0x5a, 0x8f, 0xdc, 0xf9, 0xff,
        0x1d, 0xe9, 0xa1, 0xd8, 0xe6, 0xb4, 0x47, 0xef,
        0x6e, 0xf7, 0xb7, 0x98, 0x28, 0x66, 0x6e, 0x45,
        0x81, 0xe7, 0x90, 0x12, 0xaf, 0x34, 0xdd, 0xd9,
        0xe2, 0xf0, 0x37, 0x58, 0x9b, 0x29, 0x2d, 0xb3,
        0xe6, 0x7c, 0x03, 0x67, 0x45, 0xfa, 0x22, 0xe7,
        0xe9, 0xb7, 0x37, 0x3b },
      { 0x00 },
      { 0xce, 0xa7, 0x40, 0x3d, 0x4d, 0x60, 0x6b, 0x6e,
        0x07, 0x4e, 0xc5, 0xd3, 0xba, 0xf3, 0x9d, 0x18 },
      { 0x52, 0x2d, 0xc1, 0xf0, 0x99, 0x56, 0x7d, 0x07,
        0xf4, 0x7f, 0x37, 0xa3, 0x2a, 0x84, 0x42, 0x7d,
        0x64, 0x3a, 0x8c, 0xdc, 0xbf, 0xe5, 0xc0, 0xc9,
        0x75, 0x98, 0xa2, 0xbd, 0x25, 0x55, 0xd1, 0xaa,
        0x8c, 0xb0, 0x8e, 0x48, 0x59, 0x0d, 0xbb, 0x3d,
        0xa7, 0xb0, 0x8b, 0x10, 0x56, 0x82, 0x88, 0x38,
        0xc5, 0xf6, 0x1e, 0x63, 0x93, 0xba, 0x7a, 0x0a,
        0xbc, 0xc9, 0xf6, 0x62, 0x89, 0x80, 0x15, 0xad },
      { 0x52, 0x2d, 0xc1, 0xf0, 0x99, 0x56, 0x7d, 0x07,
        0xf4, 0x7f, 0x37, 0xa3, 0x2a, 0x84, 0x42, 0x7d,
        0x64, 0x3a, 0x8c, 0xdc, 0xbf, 0xe5, 0xc0, 0xc9,
        0x75, 0x98, 0xa2, 0xbd, 0x25, 0x55, 0xd1, 0xaa,
        0x8c, 0xb0, 0x8e, 0x48, 0x59, 0x0d, 0xbb, 0x3d,
        0xa7, 0xb0, 0x8b, 0x10, 0x56, 0x82, 0x88, 0x38,
        0xc5, 0xf6, 0x1e, 0x63, 0x93, 0xba, 0x7a, 0x0a,
        0xbc, 0xc9, 0xf6, 0x62 },
      { 0xc3, 0x76, 0x2d, 0xf1, 0xca, 0x78, 0x7d, 0x32,
        0xae, 0x47, 0xc1, 0x3b, 0xf1, 0x98, 0x44, 0xcb,
        0xaf, 0x1a, 0xe1, 0x4d, 0x0b, 0x97, 0x6a, 0xfa,
        0xc5, 0x2f, 0xf7, 0xd7, 0x9b, 0xba, 0x9d, 0xe0,
        0xfe, 0xb5, 0x82, 0xd3, 0x39, 0x34, 0xa4, 0xf0,
        0x95, 0x4c, 0xc2, 0x36, 0x3b, 0xc7, 0x3f, 0x78,
        0x62, 0xac, 0x43, 0x0e, 0x64, 0xab, 0xe4, 0x99,
        0xf4, 0x7c, 0x9b, 0x1f },
      { 0x5a, 0x8d, 0xef, 0x2f, 0x0c, 0x9e, 0x53, 0xf1,
        0xf7, 0x5d, 0x78, 0x53, 0x65, 0x9e, 0x2a, 0x20,
        0xee, 0xb2, 0xb2, 0x2a, 0xaf, 0xde, 0x64, 0x19,
        0xa0, 0x58, 0xab, 0x4f, 0x6f, 0x74, 0x6b, 0xf4,
        0x0f, 0xc0, 0xc3, 0xb7, 0x80, 0xf2, 0x44, 0x45,
        0x2d, 0xa3, 0xeb, 0xf1, 0xc5, 0xd8, 0x2c, 0xde,
        0xa2, 0x41, 0x89, 0x97, 0x20, 0x0e, 0xf8, 0x2e,
        0x44, 0xae, 0x7e, 0x3f },
  };
  
  static const unsigned char tag_test_data[MAX_TESTS * 3][16] =
  {
      { 0x58, 0xe2, 0xfc, 0xce, 0xfa, 0x7e, 0x30, 0x61,
        0x36, 0x7f, 0x1d, 0x57, 0xa4, 0xe7, 0x45, 0x5a },
      { 0xab, 0x6e, 0x47, 0xd4, 0x2c, 0xec, 0x13, 0xbd,
        0xf5, 0x3a, 0x67, 0xb2, 0x12, 0x57, 0xbd, 0xdf },
      { 0x4d, 0x5c, 0x2a, 0xf3, 0x27, 0xcd, 0x64, 0xa6,
        0x2c, 0xf3, 0x5a, 0xbd, 0x2b, 0xa6, 0xfa, 0xb4 },
      { 0x5b, 0xc9, 0x4f, 0xbc, 0x32, 0x21, 0xa5, 0xdb,
        0x94, 0xfa, 0xe9, 0x5a, 0xe7, 0x12, 0x1a, 0x47 },
      { 0x36, 0x12, 0xd2, 0xe7, 0x9e, 0x3b, 0x07, 0x85,
        0x56, 0x1b, 0xe1, 0x4a, 0xac, 0xa2, 0xfc, 0xcb },
      { 0x61, 0x9c, 0xc5, 0xae, 0xff, 0xfe, 0x0b, 0xfa,
        0x46, 0x2a, 0xf4, 0x3c, 0x16, 0x99, 0xd0, 0x50 },
      { 0xcd, 0x33, 0xb2, 0x8a, 0xc7, 0x73, 0xf7, 0x4b,
        0xa0, 0x0e, 0xd1, 0xf3, 0x12, 0x57, 0x24, 0x35 },
      { 0x2f, 0xf5, 0x8d, 0x80, 0x03, 0x39, 0x27, 0xab,
        0x8e, 0xf4, 0xd4, 0x58, 0x75, 0x14, 0xf0, 0xfb },
      { 0x99, 0x24, 0xa7, 0xc8, 0x58, 0x73, 0x36, 0xbf,
        0xb1, 0x18, 0x02, 0x4d, 0xb8, 0x67, 0x4a, 0x14 },
      { 0x25, 0x19, 0x49, 0x8e, 0x80, 0xf1, 0x47, 0x8f,
        0x37, 0xba, 0x55, 0xbd, 0x6d, 0x27, 0x61, 0x8c },
      { 0x65, 0xdc, 0xc5, 0x7f, 0xcf, 0x62, 0x3a, 0x24,
        0x09, 0x4f, 0xcc, 0xa4, 0x0d, 0x35, 0x33, 0xf8 },
      { 0xdc, 0xf5, 0x66, 0xff, 0x29, 0x1c, 0x25, 0xbb,
        0xb8, 0x56, 0x8f, 0xc3, 0xd3, 0x76, 0xa6, 0xd9 },
      { 0x53, 0x0f, 0x8a, 0xfb, 0xc7, 0x45, 0x36, 0xb9,
        0xa9, 0x63, 0xb4, 0xf1, 0xc4, 0xcb, 0x73, 0x8b },
      { 0xd0, 0xd1, 0xc8, 0xa7, 0x99, 0x99, 0x6b, 0xf0,
        0x26, 0x5b, 0x98, 0xb5, 0xd4, 0x8a, 0xb9, 0x19 },
      { 0xb0, 0x94, 0xda, 0xc5, 0xd9, 0x34, 0x71, 0xbd,
        0xec, 0x1a, 0x50, 0x22, 0x70, 0xe3, 0xcc, 0x6c },
      { 0x76, 0xfc, 0x6e, 0xce, 0x0f, 0x4e, 0x17, 0x68,
        0xcd, 0xdf, 0x88, 0x53, 0xbb, 0x2d, 0x55, 0x1b },
      { 0x3a, 0x33, 0x7d, 0xbf, 0x46, 0xa7, 0x92, 0xc4,
        0x5e, 0x45, 0x49, 0x13, 0xfe, 0x2e, 0xa8, 0xf2 },
      { 0xa4, 0x4a, 0x82, 0x66, 0xee, 0x1c, 0x8e, 0xb0,
        0xc8, 0xb5, 0xd4, 0xcf, 0x5a, 0xe9, 0xf1, 0x9a },
  };
  
  int mbedtls_gcm_self_test( int verbose )
  {
      mbedtls_gcm_context ctx;
      unsigned char buf[64];
      unsigned char tag_buf[16];
      int i, j, ret;
      mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES;
      size_t olen;
  
      for( j = 0; j < 3; j++ )
      {
          int key_len = 128 + 64 * j;
  
          for( i = 0; i < MAX_TESTS; i++ )
          {
              mbedtls_gcm_init( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "  AES-GCM-%3d #%d (%s): ",
                                  key_len, i, "enc" );
  
              ret = mbedtls_gcm_setkey( &ctx, cipher,
                                        key_test_data[key_index_test_data[i]],
                                        key_len );
              /*
               * AES-192 is an optional feature that may be unavailable when
               * there is an alternative underlying implementation i.e. when
               * MBEDTLS_AES_ALT is defined.
               */
              if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && key_len == 192 )
              {
                  mbedtls_printf( "skipped\n" );
                  break;
              }
              else if( ret != 0 )
              {
                  goto exit;
              }
  
              ret = mbedtls_gcm_crypt_and_tag( &ctx, MBEDTLS_GCM_ENCRYPT,
                                  pt_len_test_data[i],
                                  iv_test_data[iv_index_test_data[i]],
                                  iv_len_test_data[i],
                                  additional_test_data[add_index_test_data[i]],
                                  add_len_test_data[i],
                                  pt_test_data[pt_index_test_data[i]],
                                  buf, 16, tag_buf );
  #if defined(MBEDTLS_GCM_ALT)
              /* Allow alternative implementations to only support 12-byte nonces. */
              if( ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED &&
                  iv_len_test_data[i] != 12 )
              {
                  mbedtls_printf( "skipped\n" );
                  break;
              }
  #endif /* defined(MBEDTLS_GCM_ALT) */
              if( ret != 0 )
                  goto exit;
  
              if ( memcmp( buf, ct_test_data[j * 6 + i],
                           pt_len_test_data[i] ) != 0 ||
                   memcmp( tag_buf, tag_test_data[j * 6 + i], 16 ) != 0 )
              {
                  ret = 1;
                  goto exit;
              }
  
              mbedtls_gcm_free( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "passed\n" );
  
              mbedtls_gcm_init( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "  AES-GCM-%3d #%d (%s): ",
                                  key_len, i, "dec" );
  
              ret = mbedtls_gcm_setkey( &ctx, cipher,
                                        key_test_data[key_index_test_data[i]],
                                        key_len );
              if( ret != 0 )
                  goto exit;
  
              ret = mbedtls_gcm_crypt_and_tag( &ctx, MBEDTLS_GCM_DECRYPT,
                                  pt_len_test_data[i],
                                  iv_test_data[iv_index_test_data[i]],
                                  iv_len_test_data[i],
                                  additional_test_data[add_index_test_data[i]],
                                  add_len_test_data[i],
                                  ct_test_data[j * 6 + i], buf, 16, tag_buf );
  
              if( ret != 0 )
                  goto exit;
  
              if( memcmp( buf, pt_test_data[pt_index_test_data[i]],
                          pt_len_test_data[i] ) != 0 ||
                  memcmp( tag_buf, tag_test_data[j * 6 + i], 16 ) != 0 )
              {
                  ret = 1;
                  goto exit;
              }
  
              mbedtls_gcm_free( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "passed\n" );
  
              mbedtls_gcm_init( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "  AES-GCM-%3d #%d split (%s): ",
                                  key_len, i, "enc" );
  
              ret = mbedtls_gcm_setkey( &ctx, cipher,
                                        key_test_data[key_index_test_data[i]],
                                        key_len );
              if( ret != 0 )
                  goto exit;
  
              ret = mbedtls_gcm_starts( &ctx, MBEDTLS_GCM_ENCRYPT,
                                        iv_test_data[iv_index_test_data[i]],
                                        iv_len_test_data[i] );
              if( ret != 0 )
                  goto exit;
  
              ret = mbedtls_gcm_update_ad( &ctx,
                                additional_test_data[add_index_test_data[i]],
                                add_len_test_data[i] );
              if( ret != 0 )
                  goto exit;
  
              if( pt_len_test_data[i] > 32 )
              {
                  size_t rest_len = pt_len_test_data[i] - 32;
                  ret = mbedtls_gcm_update( &ctx,
                                            pt_test_data[pt_index_test_data[i]],
                                            32,
                                            buf, sizeof( buf ), &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != 32 )
                      goto exit;
  
                  ret = mbedtls_gcm_update( &ctx,
                                            pt_test_data[pt_index_test_data[i]] + 32,
                                            rest_len,
                                            buf + 32, sizeof( buf ) - 32, &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != rest_len )
                      goto exit;
              }
              else
              {
                  ret = mbedtls_gcm_update( &ctx,
                                            pt_test_data[pt_index_test_data[i]],
                                            pt_len_test_data[i],
                                            buf, sizeof( buf ), &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != pt_len_test_data[i] )
                      goto exit;
              }
  
              ret = mbedtls_gcm_finish( &ctx, NULL, 0, tag_buf, 16 );
              if( ret != 0 )
                  goto exit;
  
              if( memcmp( buf, ct_test_data[j * 6 + i],
                          pt_len_test_data[i] ) != 0 ||
                  memcmp( tag_buf, tag_test_data[j * 6 + i], 16 ) != 0 )
              {
                  ret = 1;
                  goto exit;
              }
  
              mbedtls_gcm_free( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "passed\n" );
  
              mbedtls_gcm_init( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "  AES-GCM-%3d #%d split (%s): ",
                                  key_len, i, "dec" );
  
              ret = mbedtls_gcm_setkey( &ctx, cipher,
                                        key_test_data[key_index_test_data[i]],
                                        key_len );
              if( ret != 0 )
                  goto exit;
  
              ret = mbedtls_gcm_starts( &ctx, MBEDTLS_GCM_DECRYPT,
                                        iv_test_data[iv_index_test_data[i]],
                                        iv_len_test_data[i] );
              if( ret != 0 )
                  goto exit;
              ret = mbedtls_gcm_update_ad( &ctx,
                                additional_test_data[add_index_test_data[i]],
                                add_len_test_data[i] );
              if( ret != 0 )
                  goto exit;
  
              if( pt_len_test_data[i] > 32 )
              {
                  size_t rest_len = pt_len_test_data[i] - 32;
                  ret = mbedtls_gcm_update( &ctx,
                                            ct_test_data[j * 6 + i], 32,
                                            buf, sizeof( buf ), &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != 32 )
                      goto exit;
  
                  ret = mbedtls_gcm_update( &ctx,
                                            ct_test_data[j * 6 + i] + 32,
                                            rest_len,
                                            buf + 32, sizeof( buf ) - 32, &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != rest_len )
                      goto exit;
              }
              else
              {
                  ret = mbedtls_gcm_update( &ctx,
                                            ct_test_data[j * 6 + i],
                                            pt_len_test_data[i],
                                            buf, sizeof( buf ), &olen );
                  if( ret != 0 )
                      goto exit;
                  if( olen != pt_len_test_data[i] )
                      goto exit;
              }
  
              ret = mbedtls_gcm_finish( &ctx, NULL, 0, tag_buf, 16 );
              if( ret != 0 )
                  goto exit;
  
              if( memcmp( buf, pt_test_data[pt_index_test_data[i]],
                          pt_len_test_data[i] ) != 0 ||
                  memcmp( tag_buf, tag_test_data[j * 6 + i], 16 ) != 0 )
              {
                  ret = 1;
                  goto exit;
              }
  
              mbedtls_gcm_free( &ctx );
  
              if( verbose != 0 )
                  mbedtls_printf( "passed\n" );
          }
      }
  
      if( verbose != 0 )
          mbedtls_printf( "\n" );
  
      ret = 0;
  
  exit:
      if( ret != 0 )
      {
          if( verbose != 0 )
              mbedtls_printf( "failed\n" );
          mbedtls_gcm_free( &ctx );
      }
  
      return( ret );
  }
  
  #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
  
  #endif /* MBEDTLS_GCM_C */
  