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AES: fold the core and outer routines together.
The outer routines are the ones which handle the CBC encrypt, CBC decrypt and SDCTR cipher modes. Previously each of those had to be able to dispatch to one of the per-block-size core routines, which made it worth dividing the system up into two layers. But now there's only one set of core routines, they may as well be inlined into the outer ones. Also as part of this commit, the nasty undef/redef of MAKEWORD and LASTWORD have been removed, and the different macro definitions now have different macro _names_, to make it clearer which one is used where.
This commit is contained in:
Pavel I. Kryukov
Simon Tatham
parent
5592312636
commit
0816e2b1a0
303
sshaes.c
303
sshaes.c
@ -645,110 +645,6 @@ static const word32 D3[256] = {
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0xcb84617b, 0x32b670d5, 0x6c5c7448, 0xb85742d0,
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};
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/*
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* Common macros in both the encryption and decryption routines.
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*/
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#define ADD_ROUND_KEY_4 (block[0]^=*keysched++, block[1]^=*keysched++, \
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block[2]^=*keysched++, block[3]^=*keysched++)
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#define MOVEWORD(i) ( block[i] = newstate[i] )
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/*
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* Macros for the encryption routine.
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*/
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#define MAKEWORD(i) ( newstate[i] = (E0[(block[i] >> 24) & 0xFF] ^ \
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E1[(block[(i+C1)%NB] >> 16) & 0xFF] ^ \
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E2[(block[(i+C2)%NB] >> 8) & 0xFF] ^ \
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E3[block[(i+C3)%NB] & 0xFF]) )
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#define LASTWORD(i) ( newstate[i] = (Sbox[(block[i] >> 24) & 0xFF] << 24) | \
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(Sbox[(block[(i+C1)%NB] >> 16) & 0xFF] << 16) | \
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(Sbox[(block[(i+C2)%NB] >> 8) & 0xFF] << 8) | \
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(Sbox[(block[(i+C3)%NB] ) & 0xFF] ) )
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/*
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* Core encrypt routine, expecting word32 inputs read big-endian
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* from the byte-oriented input stream.
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*/
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static void aes_encrypt(AESContext * ctx, word32 * block)
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{
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int i;
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static const int C1 = 1, C2 = 2, C3 = 3;
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word32 *keysched = ctx->keysched;
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word32 newstate[4];
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for (i = 0; i < ctx->Nr - 1; i++) {
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ADD_ROUND_KEY_4;
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MAKEWORD(0);
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MAKEWORD(1);
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MAKEWORD(2);
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MAKEWORD(3);
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MOVEWORD(0);
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MOVEWORD(1);
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MOVEWORD(2);
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MOVEWORD(3);
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}
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ADD_ROUND_KEY_4;
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LASTWORD(0);
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LASTWORD(1);
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LASTWORD(2);
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LASTWORD(3);
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MOVEWORD(0);
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MOVEWORD(1);
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MOVEWORD(2);
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MOVEWORD(3);
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ADD_ROUND_KEY_4;
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}
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#undef MAKEWORD
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#undef LASTWORD
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/*
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* Macros for the decryption routine.
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*/
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#define MAKEWORD(i) ( newstate[i] = (D0[(block[i] >> 24) & 0xFF] ^ \
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D1[(block[(i+C1)%NB] >> 16) & 0xFF] ^ \
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D2[(block[(i+C2)%NB] >> 8) & 0xFF] ^ \
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D3[block[(i+C3)%NB] & 0xFF]) )
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#define LASTWORD(i) (newstate[i] = (Sboxinv[(block[i] >> 24) & 0xFF] << 24) | \
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(Sboxinv[(block[(i+C1)%NB] >> 16) & 0xFF] << 16) | \
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(Sboxinv[(block[(i+C2)%NB] >> 8) & 0xFF] << 8) | \
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(Sboxinv[(block[(i+C3)%NB] ) & 0xFF] ) )
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/*
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* Core decrypt routine, expecting word32 inputs read big-endian
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* from the byte-oriented input stream.
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*/
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static void aes_decrypt(AESContext * ctx, word32 * block)
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{
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int i;
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static const int C1 = 4 - 1, C2 = 4 - 2, C3 = 4 - 3;
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word32 *keysched = ctx->invkeysched;
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word32 newstate[4];
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for (i = 0; i < ctx->Nr - 1; i++) {
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ADD_ROUND_KEY_4;
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MAKEWORD(0);
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MAKEWORD(1);
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MAKEWORD(2);
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MAKEWORD(3);
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MOVEWORD(0);
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MOVEWORD(1);
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MOVEWORD(2);
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MOVEWORD(3);
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}
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ADD_ROUND_KEY_4;
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LASTWORD(0);
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LASTWORD(1);
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LASTWORD(2);
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LASTWORD(3);
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MOVEWORD(0);
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MOVEWORD(1);
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MOVEWORD(2);
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MOVEWORD(3);
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ADD_ROUND_KEY_4;
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}
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#undef MAKEWORD
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#undef LASTWORD
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/*
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* Set up an AESContext. `keylen' is measured in
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* bytes; it can be either 16 (128-bit), 24 (192-bit), or 32
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@ -762,9 +658,6 @@ static void aes_setup(AESContext * ctx, unsigned char *key, int keylen)
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assert(keylen == 16 || keylen == 24 || keylen == 32);
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/*
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* Now do the key setup itself.
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*/
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Nk = keylen / 4;
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rconst = 1;
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for (i = 0; i < (ctx->Nr + 1) * NB; i++) {
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@ -827,23 +720,139 @@ static void aes_setup(AESContext * ctx, unsigned char *key, int keylen)
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}
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}
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/*
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* Software encrypt/decrypt macros
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*/
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#define ADD_ROUND_KEY (block[0]^=*keysched++, \
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block[1]^=*keysched++, \
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block[2]^=*keysched++, \
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block[3]^=*keysched++)
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#define MOVEWORD(i) ( block[i] = newstate[i] )
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#define ENCWORD(i) ( newstate[i] = (E0[(block[i ] >> 24) & 0xFF] ^ \
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E1[(block[(i+1)%NB] >> 16) & 0xFF] ^ \
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E2[(block[(i+2)%NB] >> 8) & 0xFF] ^ \
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E3[ block[(i+3)%NB] & 0xFF]) )
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#define ENCROUND { ENCWORD(0); ENCWORD(1); ENCWORD(2); ENCWORD(3); \
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MOVEWORD(0); MOVEWORD(1); MOVEWORD(2); MOVEWORD(3); ADD_ROUND_KEY; }
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#define ENCLASTWORD(i) ( newstate[i] = \
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(Sbox[(block[i] >> 24) & 0xFF] << 24) | \
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(Sbox[(block[(i+1)%NB] >> 16) & 0xFF] << 16) | \
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(Sbox[(block[(i+2)%NB] >> 8) & 0xFF] << 8) | \
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(Sbox[(block[(i+3)%NB] ) & 0xFF] ) )
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#define ENCLASTROUND { ENCLASTWORD(0); ENCLASTWORD(1); ENCLASTWORD(2); ENCLASTWORD(3); \
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MOVEWORD(0); MOVEWORD(1); MOVEWORD(2); MOVEWORD(3); ADD_ROUND_KEY; }
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#define DECWORD(i) ( newstate[i] = (D0[(block[i] >> 24) & 0xFF] ^ \
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D1[(block[(i+3)%NB] >> 16) & 0xFF] ^ \
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D2[(block[(i+2)%NB] >> 8) & 0xFF] ^ \
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D3[ block[(i+1)%NB] & 0xFF]) )
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#define DECROUND { DECWORD(0); DECWORD(1); DECWORD(2); DECWORD(3); \
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MOVEWORD(0); MOVEWORD(1); MOVEWORD(2); MOVEWORD(3); ADD_ROUND_KEY; }
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#define DECLASTWORD(i) (newstate[i] = \
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(Sboxinv[(block[i] >> 24) & 0xFF] << 24) | \
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(Sboxinv[(block[(i+3)%NB] >> 16) & 0xFF] << 16) | \
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(Sboxinv[(block[(i+2)%NB] >> 8) & 0xFF] << 8) | \
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(Sboxinv[(block[(i+1)%NB] ) & 0xFF] ) )
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#define DECLASTROUND { DECLASTWORD(0); DECLASTWORD(1); DECLASTWORD(2); DECLASTWORD(3); \
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MOVEWORD(0); MOVEWORD(1); MOVEWORD(2); MOVEWORD(3); ADD_ROUND_KEY; }
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/*
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* Software AES encrypt/decrypt core
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*/
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static void aes_encrypt_cbc(unsigned char *blk, int len, AESContext * ctx)
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{
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word32 block[4];
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unsigned char* finish = blk + len;
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int i;
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assert((len & 15) == 0);
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memcpy(block, ctx->iv, sizeof(block));
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while (blk < finish) {
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word32 *keysched = ctx->keysched;
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word32 newstate[4];
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for (i = 0; i < 4; i++)
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block[i] ^= GET_32BIT_MSB_FIRST(blk + 4 * i);
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ADD_ROUND_KEY;
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switch (ctx->Nr) {
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case 14:
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ENCROUND;
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ENCROUND;
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case 12:
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ENCROUND;
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ENCROUND;
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case 10:
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCLASTROUND;
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break;
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default:
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assert(0);
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}
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for (i = 0; i < 4; i++)
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PUT_32BIT_MSB_FIRST(blk + 4 * i, block[i]);
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blk += 16;
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}
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memcpy(ctx->iv, block, sizeof(block));
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}
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static void aes_sdctr(unsigned char *blk, int len, AESContext *ctx)
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{
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word32 iv[4];
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unsigned char* finish = blk + len;
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int i;
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assert((len & 15) == 0);
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memcpy(iv, ctx->iv, sizeof(iv));
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while (len > 0) {
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for (i = 0; i < 4; i++)
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iv[i] ^= GET_32BIT_MSB_FIRST(blk + 4 * i);
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aes_encrypt(ctx, iv);
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for (i = 0; i < 4; i++)
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PUT_32BIT_MSB_FIRST(blk + 4 * i, iv[i]);
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while (blk < finish) {
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word32 *keysched = ctx->keysched;
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word32 newstate[4], block[4], tmp;
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memcpy(block, iv, sizeof(block));
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ADD_ROUND_KEY;
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switch (ctx->Nr) {
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case 14:
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ENCROUND;
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ENCROUND;
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case 12:
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ENCROUND;
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ENCROUND;
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case 10:
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCROUND;
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ENCLASTROUND;
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break;
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default:
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assert(0);
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}
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for (i = 0; i < 4; i++) {
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tmp = GET_32BIT_MSB_FIRST(blk + 4 * i);
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PUT_32BIT_MSB_FIRST(blk + 4 * i, tmp ^ block[i]);
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}
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for (i = 3; i >= 0; i--)
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if ((iv[i] = (iv[i] + 1) & 0xffffffff) != 0)
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break;
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blk += 16;
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len -= 16;
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}
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memcpy(ctx->iv, iv, sizeof(iv));
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@ -851,49 +860,47 @@ static void aes_encrypt_cbc(unsigned char *blk, int len, AESContext * ctx)
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static void aes_decrypt_cbc(unsigned char *blk, int len, AESContext * ctx)
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{
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word32 iv[4], x[4], ct[4];
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word32 iv[4];
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unsigned char* finish = blk + len;
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int i;
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assert((len & 15) == 0);
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memcpy(iv, ctx->iv, sizeof(iv));
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while (len > 0) {
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for (i = 0; i < 4; i++)
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x[i] = ct[i] = GET_32BIT_MSB_FIRST(blk + 4 * i);
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aes_decrypt(ctx, x);
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while (blk < finish) {
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word32 *keysched = ctx->invkeysched;
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word32 newstate[4], ct[4], block[4];
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for (i = 0; i < 4; i++)
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block[i] = ct[i] = GET_32BIT_MSB_FIRST(blk + 4 * i);
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ADD_ROUND_KEY;
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switch (ctx->Nr) {
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case 14:
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DECROUND;
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DECROUND;
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case 12:
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DECROUND;
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DECROUND;
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case 10:
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECROUND;
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DECLASTROUND;
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break;
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default:
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assert(0);
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}
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for (i = 0; i < 4; i++) {
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PUT_32BIT_MSB_FIRST(blk + 4 * i, iv[i] ^ x[i]);
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iv[i] = ct[i];
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PUT_32BIT_MSB_FIRST(blk + 4 * i, iv[i] ^ block[i]);
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iv[i] = ct[i];
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}
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blk += 16;
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len -= 16;
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}
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memcpy(ctx->iv, iv, sizeof(iv));
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}
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static void aes_sdctr(unsigned char *blk, int len, AESContext *ctx)
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{
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word32 iv[4], b[4], tmp;
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int i;
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assert((len & 15) == 0);
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memcpy(iv, ctx->iv, sizeof(iv));
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while (len > 0) {
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memcpy(b, iv, sizeof(b));
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aes_encrypt(ctx, b);
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for (i = 0; i < 4; i++) {
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tmp = GET_32BIT_MSB_FIRST(blk + 4 * i);
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PUT_32BIT_MSB_FIRST(blk + 4 * i, tmp ^ b[i]);
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}
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for (i = 3; i >= 0; i--)
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if ((iv[i] = (iv[i] + 1) & 0xffffffff) != 0)
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break;
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blk += 16;
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len -= 16;
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}
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memcpy(ctx->iv, iv, sizeof(iv));
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