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https://github.com/Laupetin/OpenAssetTools.git
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76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*/
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#include "tomcrypt.h"
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/**
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@file xcbc_done.c
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XCBC Support, terminate the state
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*/
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#ifdef LTC_XCBC
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/** Terminate the XCBC-MAC state
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@param xcbc XCBC state to terminate
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@param out [out] Destination for the MAC tag
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@param outlen [in/out] Destination size and final tag size
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Return CRYPT_OK on success
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*/
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int xcbc_done(xcbc_state *xcbc, unsigned char *out, unsigned long *outlen)
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{
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int err, x;
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LTC_ARGCHK(xcbc != NULL);
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LTC_ARGCHK(out != NULL);
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/* check structure */
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if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) {
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return err;
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}
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if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) ||
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(xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) {
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return CRYPT_INVALID_ARG;
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}
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/* which key do we use? */
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if (xcbc->buflen == xcbc->blocksize) {
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/* k2 */
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for (x = 0; x < xcbc->blocksize; x++) {
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xcbc->IV[x] ^= xcbc->K[1][x];
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}
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} else {
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xcbc->IV[xcbc->buflen] ^= 0x80;
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/* k3 */
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for (x = 0; x < xcbc->blocksize; x++) {
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xcbc->IV[x] ^= xcbc->K[2][x];
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}
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}
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/* encrypt */
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cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
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cipher_descriptor[xcbc->cipher].done(&xcbc->key);
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/* extract tag */
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for (x = 0; x < xcbc->blocksize && (unsigned long)x < *outlen; x++) {
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out[x] = xcbc->IV[x];
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}
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*outlen = x;
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#ifdef LTC_CLEAN_STACK
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zeromem(xcbc, sizeof(*xcbc));
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#endif
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return CRYPT_OK;
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}
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#endif
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/* ref: HEAD -> master, tag: v1.18.2 */
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/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
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/* commit time: 2018-07-01 22:49:01 +0200 */
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