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 #include "tomcrypt.h" 12 13 /** 14 @file f9_done.c 15 f9 Support, terminate the state 16 */ 17 18 #ifdef LTC_F9_MODE 19 20 /** Terminate the f9-MAC state 21 @param f9 f9 state to terminate 22 @param out [out] Destination for the MAC tag 23 @param outlen [in/out] Destination size and final tag size 24 Return CRYPT_OK on success 25 */ 26 int f9_done(f9_state *f9, unsigned char *out, unsigned long *outlen) 27 { 28 int err, x; 29 LTC_ARGCHK(f9 != NULL); 30 LTC_ARGCHK(out != NULL); 31 32 /* check structure */ 33 if ((err = cipher_is_valid(f9->cipher)) != CRYPT_OK) { 34 return err; 35 } 36 37 if ((f9->blocksize > cipher_descriptor[f9->cipher].block_length) || (f9->blocksize < 0) || 38 (f9->buflen > f9->blocksize) || (f9->buflen < 0)) { 39 return CRYPT_INVALID_ARG; 40 } 41 42 if (f9->buflen != 0) { 43 /* encrypt */ 44 cipher_descriptor[f9->cipher].ecb_encrypt(f9->IV, f9->IV, &f9->key); 45 f9->buflen = 0; 46 for (x = 0; x < f9->blocksize; x++) { 47 f9->ACC[x] ^= f9->IV[x]; 48 } 49 } 50 51 /* schedule modified key */ 52 if ((err = cipher_descriptor[f9->cipher].setup(f9->akey, f9->keylen, 0, &f9->key)) != CRYPT_OK) { 53 return err; 54 } 55 56 /* encrypt the ACC */ 57 cipher_descriptor[f9->cipher].ecb_encrypt(f9->ACC, f9->ACC, &f9->key); 58 cipher_descriptor[f9->cipher].done(&f9->key); 59 60 /* extract tag */ 61 for (x = 0; x < f9->blocksize && (unsigned long)x < *outlen; x++) { 62 out[x] = f9->ACC[x]; 63 } 64 *outlen = x; 65 66 #ifdef LTC_CLEAN_STACK 67 zeromem(f9, sizeof(*f9)); 68 #endif 69 return CRYPT_OK; 70 } 71 72 #endif 73 74 /* $Source: /cvs/libtom/libtomcrypt/src/mac/f9/f9_done.c,v $ */ 75 /* $Revision: 1.5 $ */ 76 /* $Date: 2006/11/09 01:53:32 $ */ 77 78
