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aes: Remove AES-XEX

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AES-XEX is a building block for other cryptographic standards and not yet a
standard in and of itself. We'll just provide the standardized AES-XTS
algorithm, and not AES-XEX. The AES-XTS algorithm and interface provided
can be used to perform the AES-XEX algorithm when the length of the input
is a multiple of the AES block size.
This commit is contained in:
Jaeden Amero 2018-05-17 16:42:08 +01:00
parent 010c2cb456
commit e9ecf00007
8 changed files with 2 additions and 3794 deletions
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58
library/aes.c
View file

@ -983,64 +983,6 @@ int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */
#if defined(MBEDTLS_CIPHER_MODE_XEX)
/*
* AES-XEX buffer encryption/decryption
*/
int mbedtls_aes_crypt_xex( mbedtls_aes_context *crypt_ctx,
mbedtls_aes_context *tweak_ctx,
int mode,
size_t length,
unsigned char iv[16],
const unsigned char *input,
unsigned char *output )
{
union xex_buf128 {
uint8_t u8[16];
uint64_t u64[2];
};
union xex_buf128 scratch;
union xex_buf128 t_buf;
union xex_buf128 *inbuf;
union xex_buf128 *outbuf;
inbuf = (union xex_buf128*)input;
outbuf = (union xex_buf128*)output;
if( length % 16 )
return( MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH );
mbedtls_aes_crypt_ecb( tweak_ctx, MBEDTLS_AES_ENCRYPT, iv, t_buf.u8 );
goto first;
do
{
mbedtls_gf128mul_x_ble( t_buf.u8, t_buf.u8 );
first:
/* PP <- T xor P */
scratch.u64[0] = (uint64_t)( inbuf->u64[0] ^ t_buf.u64[0] );
scratch.u64[1] = (uint64_t)( inbuf->u64[1] ^ t_buf.u64[1] );
/* CC <- E(Key2,PP) */
mbedtls_aes_crypt_ecb( crypt_ctx, mode, scratch.u8, outbuf->u8 );
/* C <- T xor CC */
outbuf->u64[0] = (uint64_t)( outbuf->u64[0] ^ t_buf.u64[0] );
outbuf->u64[1] = (uint64_t)( outbuf->u64[1] ^ t_buf.u64[1] );
inbuf += 1;
outbuf += 1;
length -= 16;
} while( length > 0 );
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_XEX */
#if defined(MBEDTLS_CIPHER_MODE_XTS)
/* Endianess with 64 bits values */