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Import code from previous AssetBuilder version

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Jan
2019-09-24 10:45:09 +02:00
parent 5609557516
commit 0d8432d4f7
919 changed files with 154412 additions and 26 deletions
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99
thirdparty/libtomcrypt/modes/ctr/ctr_start.c vendored Normal file
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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.
*/
#include "tomcrypt.h"
/**
@file ctr_start.c
CTR implementation, start chain, Tom St Denis
*/
#ifdef LTC_CTR_MODE
/**
Initialize a CTR context
@param cipher The index of the cipher desired
@param IV The initialization vector
@param key The secret key
@param keylen The length of the secret key (octets)
@param num_rounds Number of rounds in the cipher desired (0 for default)
@param ctr_mode The counter mode (CTR_COUNTER_LITTLE_ENDIAN or CTR_COUNTER_BIG_ENDIAN)
@param ctr The CTR state to initialize
@return CRYPT_OK if successful
*/
int ctr_start( int cipher,
const unsigned char *IV,
const unsigned char *key, int keylen,
int num_rounds, int ctr_mode,
symmetric_CTR *ctr)
{
int x, err;
LTC_ARGCHK(IV != NULL);
LTC_ARGCHK(key != NULL);
LTC_ARGCHK(ctr != NULL);
/* bad param? */
if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
return err;
}
/* ctrlen == counter width */
ctr->ctrlen = (ctr_mode & 255) ? (ctr_mode & 255) : cipher_descriptor[cipher].block_length;
if (ctr->ctrlen > cipher_descriptor[cipher].block_length) {
return CRYPT_INVALID_ARG;
}
if ((ctr_mode & 0x1000) == CTR_COUNTER_BIG_ENDIAN) {
ctr->ctrlen = cipher_descriptor[cipher].block_length - ctr->ctrlen;
}
/* setup cipher */
if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &ctr->key)) != CRYPT_OK) {
return err;
}
/* copy ctr */
ctr->blocklen = cipher_descriptor[cipher].block_length;
ctr->cipher = cipher;
ctr->padlen = 0;
ctr->mode = ctr_mode & 0x1000;
for (x = 0; x < ctr->blocklen; x++) {
ctr->ctr[x] = IV[x];
}
if (ctr_mode & LTC_CTR_RFC3686) {
/* increment the IV as per RFC 3686 */
if (ctr->mode == CTR_COUNTER_LITTLE_ENDIAN) {
/* little-endian */
for (x = 0; x < ctr->ctrlen; x++) {
ctr->ctr[x] = (ctr->ctr[x] + (unsigned char)1) & (unsigned char)255;
if (ctr->ctr[x] != (unsigned char)0) {
break;
}
}
} else {
/* big-endian */
for (x = ctr->blocklen-1; x >= ctr->ctrlen; x--) {
ctr->ctr[x] = (ctr->ctr[x] + (unsigned char)1) & (unsigned char)255;
if (ctr->ctr[x] != (unsigned char)0) {
break;
}
}
}
}
return cipher_descriptor[ctr->cipher].ecb_encrypt(ctr->ctr, ctr->pad, &ctr->key);
}
#endif
/* ref: HEAD -> master, tag: v1.18.2 */
/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
/* commit time: 2018-07-01 22:49:01 +0200 */