mbedtls how to en/decrypt with aes ecb,cbc,ctr,cfb,ofb,xts
If you want to know the basic knowledge of ECB/CBC/CTR/PCBC/CFB/OFB, you can check the below wiki
https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
The source code path of how to use ecb/cbc/ctr/cfb/ofb/xts as below show:
mbedtls/library/aes.c
This is the self test of aes, if you want to use the below aes cipher type to handler you data, you can refer to the following code.
#if defined(MBEDTLS_SELF_TEST)
/*
* Checkup routine
*/
int mbedtls_aes_self_test( int verbose )
{
int ret = 0, i, j, u, mode;
unsigned int keybits;
unsigned char key[32];
unsigned char buf[64];
const unsigned char *aes_tests;
#if defined(MBEDTLS_CIPHER_MODE_CBC) || defined(MBEDTLS_CIPHER_MODE_CFB)
unsigned char iv[16];
#endif
#if defined(MBEDTLS_CIPHER_MODE_CBC)
unsigned char prv[16];
#endif
#if defined(MBEDTLS_CIPHER_MODE_CTR) || defined(MBEDTLS_CIPHER_MODE_CFB) || \
defined(MBEDTLS_CIPHER_MODE_OFB)
size_t offset;
#endif
#if defined(MBEDTLS_CIPHER_MODE_CTR) || defined(MBEDTLS_CIPHER_MODE_XTS)
int len;
#endif
#if defined(MBEDTLS_CIPHER_MODE_CTR)
unsigned char nonce_counter[16];
unsigned char stream_block[16];
#endif
mbedtls_aes_context ctx;
memset( key, 0, 32 );
mbedtls_aes_init( &ctx );
/*
* ECB mode
*/
for( i = 0; i < 6; i++ )
{
u = i >> 1;
keybits = 128 + u * 64;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-ECB-%3d (%s): ", keybits,
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memset( buf, 0, 16 );
if( mode == MBEDTLS_AES_DECRYPT )
{
/*设置aes解密的key*/
ret = mbedtls_aes_setkey_dec( &ctx, key, keybits );
aes_tests = aes_test_ecb_dec[u];
}
else
{
/*设置aes加密的key*/
ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
aes_tests = aes_test_ecb_enc[u];
}
/*
* 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 && keybits == 192 )
{
mbedtls_printf( "skipped\n" );
continue;
}
else if( ret != 0 )
{
goto exit;
}
for( j = 0; j < 10000; j++ )
{
/*对buf[16]={0}的数据依次加密10000次，将结果存入buf中*/
ret = mbedtls_aes_crypt_ecb( &ctx, mode, buf, buf );
if( ret != 0 )
goto exit;
}
/*比对加解密之后的数据是否和预期的结果一致*/
if( memcmp( buf, aes_tests, 16 ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
* CBC mode
*/
for( i = 0; i < 6; i++ )
{
u = i >> 1;
keybits = 128 + u * 64;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-CBC-%3d (%s): ", keybits,
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memset( iv , 0, 16 );
memset( prv, 0, 16 );
memset( buf, 0, 16 );
if( mode == MBEDTLS_AES_DECRYPT )
{
ret = mbedtls_aes_setkey_dec( &ctx, key, keybits );
aes_tests = aes_test_cbc_dec[u];
}
else
{
ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
aes_tests = aes_test_cbc_enc[u];
}
/*
* 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 && keybits == 192 )
{
mbedtls_printf( "skipped\n" );
continue;
}
else if( ret != 0 )
{
goto exit;
}
for( j = 0; j < 10000; j++ )
{
if( mode == MBEDTLS_AES_ENCRYPT )
{
unsigned char tmp[16];
memcpy( tmp, prv, 16 );
memcpy( prv, buf, 16 );
memcpy( buf, tmp, 16 );
}
ret = mbedtls_aes_crypt_cbc( &ctx, mode, 16, iv, buf, buf );
if( ret != 0 )
goto exit;
}
if( memcmp( buf, aes_tests, 16 ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
#endif /* MBEDTLS_CIPHER_MODE_CBC */
#if defined(MBEDTLS_CIPHER_MODE_CFB)
/*
* CFB128 mode
*/
for( i = 0; i < 6; i++ )
{
u = i >> 1;
keybits = 128 + u * 64;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-CFB128-%3d (%s): ", keybits,
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memcpy( iv, aes_test_cfb128_iv, 16 );
memcpy( key, aes_test_cfb128_key[u], keybits / 8 );
offset = 0;
ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
/*
* 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 && keybits == 192 )
{
mbedtls_printf( "skipped\n" );
continue;
}
else if( ret != 0 )
{
goto exit;
}
if( mode == MBEDTLS_AES_DECRYPT )
{
memcpy( buf, aes_test_cfb128_ct[u], 64 );
aes_tests = aes_test_cfb128_pt;
}
else
{
memcpy( buf, aes_test_cfb128_pt, 64 );
aes_tests = aes_test_cfb128_ct[u];
}
ret = mbedtls_aes_crypt_cfb128( &ctx, mode, 64, &offset, iv, buf, buf );
if( ret != 0 )
goto exit;
if( memcmp( buf, aes_tests, 64 ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
#endif /* MBEDTLS_CIPHER_MODE_CFB */
#if defined(MBEDTLS_CIPHER_MODE_OFB)
/*
* OFB mode
*/
for( i = 0; i < 6; i++ )
{
u = i >> 1;
keybits = 128 + u * 64;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-OFB-%3d (%s): ", keybits,
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memcpy( iv, aes_test_ofb_iv, 16 );
memcpy( key, aes_test_ofb_key[u], keybits / 8 );
offset = 0;
ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
/*
* 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 && keybits == 192 )
{
mbedtls_printf( "skipped\n" );
continue;
}
else if( ret != 0 )
{
goto exit;
}
if( mode == MBEDTLS_AES_DECRYPT )
{
memcpy( buf, aes_test_ofb_ct[u], 64 );
aes_tests = aes_test_ofb_pt;
}
else
{
memcpy( buf, aes_test_ofb_pt, 64 );
aes_tests = aes_test_ofb_ct[u];
}
ret = mbedtls_aes_crypt_ofb( &ctx, 64, &offset, iv, buf, buf );
if( ret != 0 )
goto exit;
if( memcmp( buf, aes_tests, 64 ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
#endif /* MBEDTLS_CIPHER_MODE_OFB */
#if defined(MBEDTLS_CIPHER_MODE_CTR)
/*
* CTR mode
*/
for( i = 0; i < 6; i++ )
{
u = i >> 1;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-CTR-128 (%s): ",
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memcpy( nonce_counter, aes_test_ctr_nonce_counter[u], 16 );
memcpy( key, aes_test_ctr_key[u], 16 );
offset = 0;
if( ( ret = mbedtls_aes_setkey_enc( &ctx, key, 128 ) ) != 0 )
goto exit;
len = aes_test_ctr_len[u];
if( mode == MBEDTLS_AES_DECRYPT )
{
memcpy( buf, aes_test_ctr_ct[u], len );
aes_tests = aes_test_ctr_pt[u];
}
else
{
memcpy( buf, aes_test_ctr_pt[u], len );
aes_tests = aes_test_ctr_ct[u];
}
ret = mbedtls_aes_crypt_ctr( &ctx, len, &offset, nonce_counter,
stream_block, buf, buf );
if( ret != 0 )
goto exit;
if( memcmp( buf, aes_tests, len ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
#endif /* MBEDTLS_CIPHER_MODE_CTR */
#if defined(MBEDTLS_CIPHER_MODE_XTS)
{
static const int num_tests =
sizeof(aes_test_xts_key) / sizeof(*aes_test_xts_key);
mbedtls_aes_xts_context ctx_xts;
/*
* XTS mode
*/
mbedtls_aes_xts_init( &ctx_xts );
for( i = 0; i < num_tests << 1; i++ )
{
const unsigned char *data_unit;
u = i >> 1;
mode = i & 1;
if( verbose != 0 )
mbedtls_printf( " AES-XTS-128 (%s): ",
( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
memset( key, 0, sizeof( key ) );
memcpy( key, aes_test_xts_key[u], 32 );
data_unit = aes_test_xts_data_unit[u];
len = sizeof( *aes_test_xts_ct32 );
if( mode == MBEDTLS_AES_DECRYPT )
{
ret = mbedtls_aes_xts_setkey_dec( &ctx_xts, key, 256 );
if( ret != 0)
goto exit;
memcpy( buf, aes_test_xts_ct32[u], len );
aes_tests = aes_test_xts_pt32[u];
}
else
{
ret = mbedtls_aes_xts_setkey_enc( &ctx_xts, key, 256 );
if( ret != 0)
goto exit;
memcpy( buf, aes_test_xts_pt32[u], len );
aes_tests = aes_test_xts_ct32[u];
}
ret = mbedtls_aes_crypt_xts( &ctx_xts, mode, len, data_unit,
buf, buf );
if( ret != 0 )
goto exit;
if( memcmp( buf, aes_tests, len ) != 0 )
{
ret = 1;
goto exit;
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
mbedtls_aes_xts_free( &ctx_xts );
}
#endif /* MBEDTLS_CIPHER_MODE_XTS */
ret = 0;
exit:
if( ret != 0 && verbose != 0 )
mbedtls_printf( "failed\n" );
mbedtls_aes_free( &ctx );
return( ret );
}
#endif /* MBEDTLS_SELF_TEST */