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@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 */
eax_decrypt(eax_state * eax,const unsigned char * ct,unsigned char * pt,unsigned long length)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