Mercurial > dropbear
view libtomcrypt/src/encauth/eax/eax_done.c @ 297:79bf1023cf11 agent-client
propagate from branch 'au.asn.ucc.matt.dropbear' (head 0501e6f661b5415eb76f3b312d183c3adfbfb712)
to branch 'au.asn.ucc.matt.dropbear.cli-agent' (head 01038174ec27245b51bd43a66c01ad930880f67b)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 21 Mar 2006 16:20:59 +0000 |
parents | 1b9e69c058d2 |
children | 0cbe8f6dbf9e |
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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.org */ /** @file eax_done.c EAX implementation, terminate session, by Tom St Denis */ #include "tomcrypt.h" #ifdef EAX_MODE /** Terminate an EAX session and get the tag. @param eax The EAX state @param tag [out] The destination of the authentication tag @param taglen [in/out] The max length and resulting length of the authentication tag @return CRYPT_OK if successful */ int eax_done(eax_state *eax, unsigned char *tag, unsigned long *taglen) { int err; unsigned char *headermac, *ctmac; unsigned long x, len; LTC_ARGCHK(eax != NULL); LTC_ARGCHK(tag != NULL); LTC_ARGCHK(taglen != NULL); /* allocate ram */ headermac = XMALLOC(MAXBLOCKSIZE); ctmac = XMALLOC(MAXBLOCKSIZE); if (headermac == NULL || ctmac == NULL) { if (headermac != NULL) { XFREE(headermac); } if (ctmac != NULL) { XFREE(ctmac); } return CRYPT_MEM; } /* finish ctomac */ len = MAXBLOCKSIZE; if ((err = omac_done(&eax->ctomac, ctmac, &len)) != CRYPT_OK) { goto LBL_ERR; } /* finish headeromac */ /* note we specifically don't reset len so the two lens are minimal */ if ((err = omac_done(&eax->headeromac, headermac, &len)) != CRYPT_OK) { goto LBL_ERR; } /* terminate the CTR chain */ if ((err = ctr_done(&eax->ctr)) != CRYPT_OK) { goto LBL_ERR; } /* compute N xor H xor C */ for (x = 0; x < len && x < *taglen; x++) { tag[x] = eax->N[x] ^ headermac[x] ^ ctmac[x]; } *taglen = x; err = CRYPT_OK; LBL_ERR: #ifdef LTC_CLEAN_STACK zeromem(ctmac, MAXBLOCKSIZE); zeromem(headermac, MAXBLOCKSIZE); zeromem(eax, sizeof(*eax)); #endif XFREE(ctmac); XFREE(headermac); return err; } #endif /* $Source: /cvs/libtom/libtomcrypt/src/encauth/eax/eax_done.c,v $ */ /* $Revision: 1.4 $ */ /* $Date: 2005/05/05 14:35:58 $ */