1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 2 * 3 * LibTomCrypt is a library that provides various cryptographic 4 * algorithms in a highly modular and flexible manner. 5 * 6 * The library is free for all purposes without any express 7 * guarantee it works. 8 * 9 * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com 10 */ 11 12 /** 13 @file eax_decrypt.c 14 EAX implementation, decrypt block, by Tom St Denis 15 */ 16 #include "tomcrypt.h" 17 18 #ifdef EAX_MODE 19 20 /** 21 Decrypt data with the EAX protocol 22 @param eax The EAX state 23 @param ct The ciphertext 24 @param pt [out] The plaintext 25 @param length The length (octets) of the ciphertext 26 @return CRYPT_OK if successful 27 */ 28 int eax_decrypt(eax_state *eax, const unsigned char *ct, unsigned char *pt, 29 unsigned long length) 30 { 31 int err; 32 33 LTC_ARGCHK(eax != NULL); 34 LTC_ARGCHK(pt != NULL); 35 LTC_ARGCHK(ct != NULL); 36 37 /* omac ciphertext */ 38 if ((err = omac_process(&eax->ctomac, ct, length)) != CRYPT_OK) { 39 return err; 40 } 41 42 /* decrypt */ 43 return ctr_decrypt(ct, pt, length, &eax->ctr); 44 } 45 46 #endif 47 48 /* $Source: /cvs/libtom/libtomcrypt/src/encauth/eax/eax_decrypt.c,v $ */ 49 /* $Revision: 1.4 $ */ 50 /* $Date: 2006/03/31 14:15:35 $ */ 51
