diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c')
-rw-r--r-- | core/lib/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c b/core/lib/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c new file mode 100644 index 0000000..30a81c8 --- /dev/null +++ b/core/lib/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c @@ -0,0 +1,135 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* 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://libtom.org + */ + +/** + @file eax_decrypt_verify_memory.c + EAX implementation, decrypt block of memory, by Tom St Denis +*/ +#include "tomcrypt.h" + +#ifdef LTC_EAX_MODE + +/** + Decrypt a block of memory and verify the provided MAC tag with EAX + @param cipher The index of the cipher desired + @param key The secret key + @param keylen The length of the key (octets) + @param nonce The nonce data (use once) for the session + @param noncelen The length of the nonce data. + @param header The session header data + @param headerlen The length of the header (octets) + @param ct The ciphertext + @param ctlen The length of the ciphertext (octets) + @param pt [out] The plaintext + @param tag The authentication tag provided by the encoder + @param taglen [in/out] The length of the tag (octets) + @param stat [out] The result of the decryption (1==valid tag, 0==invalid) + @return CRYPT_OK if successful regardless of the resulting tag comparison +*/ +int eax_decrypt_verify_memory(int cipher, + const unsigned char *key, unsigned long keylen, + const unsigned char *nonce, unsigned long noncelen, + const unsigned char *header, unsigned long headerlen, + const unsigned char *ct, unsigned long ctlen, + unsigned char *pt, + unsigned char *tag, unsigned long taglen, + int *stat) +{ + int err; + eax_state *eax; + unsigned char *buf; + unsigned long buflen; + + LTC_ARGCHK(stat != NULL); + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LTC_ARGCHK(tag != NULL); + + /* default to zero */ + *stat = 0; + + /* allocate ram */ + buf = XMALLOC(taglen); + eax = XMALLOC(sizeof(*eax)); + if (eax == NULL || buf == NULL) { + if (eax != NULL) { + XFREE(eax); + } + if (buf != NULL) { + XFREE(buf); + } + return CRYPT_MEM; + } + + if ((err = eax_init(eax, cipher, key, keylen, nonce, noncelen, header, headerlen)) != CRYPT_OK) { + goto LBL_ERR; + } + + if ((err = eax_decrypt(eax, ct, pt, ctlen)) != CRYPT_OK) { + goto LBL_ERR; + } + + buflen = taglen; + if ((err = eax_done(eax, buf, &buflen)) != CRYPT_OK) { + goto LBL_ERR; + } + + /* compare tags */ + if (buflen >= taglen && XMEMCMP(buf, tag, taglen) == 0) { + *stat = 1; + } + + err = CRYPT_OK; +LBL_ERR: +#ifdef LTC_CLEAN_STACK + zeromem(buf, taglen); + zeromem(eax, sizeof(*eax)); +#endif + + XFREE(eax); + XFREE(buf); + + return err; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c,v $ */ +/* $Revision: 1.7 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |