Mercurial > dropbear
view libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c @ 769:b2d4205b0897
reset terminal modes before printing a message
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 10 Apr 2013 21:32:44 +0800 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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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, [email protected], http://libtomcrypt.com */ /** @file eax_decrypt_verify_memory.c EAX implementation, decrypt block of memory, by Tom St Denis */ #include "tomcrypt.h" #ifdef 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: 1.5 $ */ /* $Date: 2006/11/01 09:28:17 $ */