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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
*/
#include "tomcrypt.h"
/**
@file pelican.c
Pelican MAC, initialize state, by Tom St Denis
*/
#ifdef PELICAN
#define ENCRYPT_ONLY
#define PELI_TAB
#include "../../ciphers/aes/aes_tab.c"
/**
Initialize a Pelican state
@param pelmac The Pelican state to initialize
@param key The secret key
@param keylen The length of the secret key (octets)
@return CRYPT_OK if successful
*/
int pelican_init(pelican_state *pelmac, const unsigned char *key, unsigned long keylen)
{
int err;
LTC_ARGCHK(pelmac != NULL);
LTC_ARGCHK(key != NULL);
#ifdef LTC_FAST
if (16 % sizeof(LTC_FAST_TYPE)) {
return CRYPT_INVALID_ARG;
}
#endif
if ((err = aes_setup(key, keylen, 0, &pelmac->K)) != CRYPT_OK) {
return err;
}
zeromem(pelmac->state, 16);
aes_ecb_encrypt(pelmac->state, pelmac->state, &pelmac->K);
pelmac->buflen = 0;
return CRYPT_OK;
}
static void four_rounds(pelican_state *pelmac)
{
ulong32 s0, s1, s2, s3, t0, t1, t2, t3;
int r;
LOAD32H(s0, pelmac->state );
LOAD32H(s1, pelmac->state + 4);
LOAD32H(s2, pelmac->state + 8);
LOAD32H(s3, pelmac->state + 12);
for (r = 0; r < 4; r++) {
t0 =
Te0(byte(s0, 3)) ^
Te1(byte(s1, 2)) ^
Te2(byte(s2, 1)) ^
Te3(byte(s3, 0));
t1 =
Te0(byte(s1, 3)) ^
Te1(byte(s2, 2)) ^
Te2(byte(s3, 1)) ^
Te3(byte(s0, 0));
t2 =
Te0(byte(s2, 3)) ^
Te1(byte(s3, 2)) ^
Te2(byte(s0, 1)) ^
Te3(byte(s1, 0));
t3 =
Te0(byte(s3, 3)) ^
Te1(byte(s0, 2)) ^
Te2(byte(s1, 1)) ^
Te3(byte(s2, 0));
s0 = t0; s1 = t1; s2 = t2; s3 = t3;
}
STORE32H(s0, pelmac->state );
STORE32H(s1, pelmac->state + 4);
STORE32H(s2, pelmac->state + 8);
STORE32H(s3, pelmac->state + 12);
}
/**
Process a block of text through Pelican
@param pelmac The Pelican MAC state
@param in The input
@param inlen The length input (octets)
@return CRYPT_OK on success
*/
int pelican_process(pelican_state *pelmac, const unsigned char *in, unsigned long inlen)
{
LTC_ARGCHK(pelmac != NULL);
LTC_ARGCHK(in != NULL);
/* check range */
if (pelmac->buflen < 0 || pelmac->buflen > 15) {
return CRYPT_INVALID_ARG;
}
#ifdef LTC_FAST
if (pelmac->buflen == 0) {
while (inlen & ~15) {
int x;
for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
*((LTC_FAST_TYPE*)((unsigned char *)pelmac->state + x)) ^= *((LTC_FAST_TYPE*)((unsigned char *)in + x));
}
four_rounds(pelmac);
in += 16;
inlen -= 16;
}
}
#endif
while (inlen--) {
pelmac->state[pelmac->buflen++] ^= *in++;
if (pelmac->buflen == 16) {
four_rounds(pelmac);
pelmac->buflen = 0;
}
}
return CRYPT_OK;
}
/**
Terminate Pelican MAC
@param pelmac The Pelican MAC state
@param out [out] The TAG
@return CRYPT_OK on sucess
*/
int pelican_done(pelican_state *pelmac, unsigned char *out)
{
LTC_ARGCHK(pelmac != NULL);
LTC_ARGCHK(out != NULL);
/* check range */
if (pelmac->buflen < 0 || pelmac->buflen > 16) {
return CRYPT_INVALID_ARG;
}
if (pelmac->buflen == 16) {
four_rounds(pelmac);
pelmac->buflen = 0;
}
pelmac->state[pelmac->buflen++] ^= 0x80;
aes_ecb_encrypt(pelmac->state, out, &pelmac->K);
aes_done(&pelmac->K);
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/mac/pelican/pelican.c,v $ */
/* $Revision: 1.18 $ */
/* $Date: 2006/04/02 13:19:10 $ */
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