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Add support for key inversion using AES-NI

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Manuel Pégourié-Gonnard 2013-12-28 15:58:30 +01:00
parent 80637c7520
commit 01e31bbffb
3 changed files with 42 additions and 0 deletions
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10
include/polarssl/aesni.h
View File

@ -81,6 +81,16 @@ int aesni_gcm_mult( unsigned char c[16],
const unsigned char a[16], const unsigned char a[16],
const unsigned char b[16] ); const unsigned char b[16] );
/**
* \brief Compute decryption round keys from encryption round keys
*
* \param invkey Round keys for the equivalent inverse cipher
* \param fwdkey Original round keys (for encryption)
* \param nr Number of rounds (that is, number of round keys minus one)
*/
void aesni_inverse_key( unsigned char *invkey,
const unsigned char *fwdkey, int nr );
#endif /* POLARSSL_HAVE_X86_64 */ #endif /* POLARSSL_HAVE_X86_64 */
#endif /* POLARSSL_AESNI_H */ #endif /* POLARSSL_AESNI_H */

10
library/aes.c
View File

@ -591,6 +591,15 @@ int aes_setkey_dec( aes_context *ctx, const unsigned char *key, unsigned int key
if( ret != 0 ) if( ret != 0 )
return( ret ); return( ret );
#if defined(POLARSSL_AESNI_C) && defined(POLARSSL_HAVE_X86_64)
if( aesni_supports( POLARSSL_AESNI_AES ) )
{
aesni_inverse_key( (unsigned char *) ctx->rk,
(const unsigned char *) cty.rk, ctx->nr );
goto done;
}
#endif
SK = cty.rk + cty.nr * 4; SK = cty.rk + cty.nr * 4;
*RK++ = *SK++; *RK++ = *SK++;
@ -614,6 +623,7 @@ int aes_setkey_dec( aes_context *ctx, const unsigned char *key, unsigned int key
*RK++ = *SK++; *RK++ = *SK++;
*RK++ = *SK++; *RK++ = *SK++;
done:
memset( &cty, 0, sizeof( aes_context ) ); memset( &cty, 0, sizeof( aes_context ) );
return( 0 ); return( 0 );

22
library/aesni.c
View File

@ -215,6 +215,28 @@ int aesni_gcm_mult( unsigned char c[16],
return( 0 ); return( 0 );
} }
/*
* Compute decryption round keys from encryption round keys
*/
void aesni_inverse_key( unsigned char *invkey,
const unsigned char *fwdkey, int nr )
{
unsigned char *ik = invkey;
const unsigned char *fk = fwdkey + 16 * nr;
memcpy( ik, fk, 16 );
for( fk -= 16, ik += 16; fk > fwdkey; fk -= 16, ik += 16 )
asm( "movdqu (%0), %%xmm0 \n"
"aesimc %%xmm0, %%xmm0 \n"
"movdqu %%xmm0, (%1) \n"
:
: "r" (fk), "r" (ik)
: "memory", "xmm0" );
memcpy( ik, fk, 16 );
}
#endif /* POLARSSL_HAVE_X86_64 */ #endif /* POLARSSL_HAVE_X86_64 */
#endif /* POLARSSL_AESNI_C */ #endif /* POLARSSL_AESNI_C */