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Add AES-NI key expansion for 256 bits

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This commit is contained in:
Manuel Pégourié-Gonnard 2013-12-29 13:50:32 +01:00
parent 47a3536a31
commit 4a5b995c26
2 changed files with 74 additions and 0 deletions
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5
include/polarssl/aes.h
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@ -55,6 +55,11 @@ extern "C" {
/**
* \brief AES context structure
*
* \note buf is able to hold 32 extra bytes, which can be used:
* - for alignment purposes if VIA padlock is used, and/or
* - to simplify key expansion in the 256-bit case by
* generating an extra round key
*/
typedef struct
{

69
library/aesni.c
View File

@ -248,6 +248,8 @@ void aesni_setkey_enc_128( unsigned char *rk,
"jmp 2f \n" // skip auxiliary routine
/*
* Finish generating the next round key.
*
* On entry xmm0 is r3:r2:r1:r0 and xmm1 is X:stuff:stuff:stuff
* with X = rot( sub( r3 ) ) ^ RCON.
*
@ -285,6 +287,72 @@ void aesni_setkey_enc_128( unsigned char *rk,
: "memory", "cc", "0" );
}
/*
* Key expansion, 256-bit case
*/
void aesni_setkey_enc_256( unsigned char *rk,
const unsigned char *key )
{
asm( "movdqu (%1), %%xmm0 \n"
"movdqu %%xmm0, (%0) \n"
"add $16, %0 \n"
"movdqu 16(%1), %%xmm1 \n"
"movdqu %%xmm1, (%0) \n"
"jmp 2f \n" // skip auxiliary routine
/*
* Finish generating the next two round keys.
*
* On entry xmm0 is r3:r2:r1:r0, xmm1 is r7:r6:r5:r4 and
* xmm2 is X:stuff:stuff:stuff with X = rot( sub( r7 )) ^ RCON
*
* On exit, xmm0 is r11:r10:r9:r8 and xmm1 is r15:r14:r13:r12
* and those have been written to the output buffer.
*/
"1: \n"
"pshufd $0xff, %%xmm2, %%xmm2 \n"
"pxor %%xmm0, %%xmm2 \n"
"pslldq $4, %%xmm0 \n"
"pxor %%xmm0, %%xmm2 \n"
"pslldq $4, %%xmm0 \n"
"pxor %%xmm0, %%xmm2 \n"
"pslldq $4, %%xmm0 \n"
"pxor %%xmm2, %%xmm0 \n"
"add $16, %0 \n"
"movdqu %%xmm0, (%0) \n"
/* Set xmm2 to stuff:Y:stuff:stuff with Y = subword( r11 )
* and proceed to generate next round key from there */
"aeskeygenassist $0, %%xmm0, %%xmm2\n"
"pshufd $0xaa, %%xmm2, %%xmm2 \n"
"pxor %%xmm1, %%xmm2 \n"
"pslldq $4, %%xmm1 \n"
"pxor %%xmm1, %%xmm2 \n"
"pslldq $4, %%xmm1 \n"
"pxor %%xmm1, %%xmm2 \n"
"pslldq $4, %%xmm1 \n"
"pxor %%xmm2, %%xmm1 \n"
"add $16, %0 \n"
"movdqu %%xmm1, (%0) \n"
"ret \n"
/*
* Main "loop" - Generating one more key than necessary,
* see definition of aes_context.buf
*/
"2: \n"
"aeskeygenassist $0x01, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x02, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x04, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x08, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x10, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x20, %%xmm1, %%xmm2 \ncall 1b \n"
"aeskeygenassist $0x40, %%xmm1, %%xmm2 \ncall 1b \n"
:
: "r" (rk), "r" (key)
: "memory", "cc", "0" );
}
/*
* Key expansion, wrapper
*/
@ -295,6 +363,7 @@ int aesni_setkey_enc( unsigned char *rk,
switch( bits )
{
case 128: aesni_setkey_enc_128( rk, key ); break;
case 256: aesni_setkey_enc_256( rk, key ); break;
default : return( POLARSSL_ERR_AES_INVALID_KEY_LENGTH );
}