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 pmac_done.c 15 PMAC implementation, terminate a session, by Tom St Denis 16 */ 17 18 #ifdef LTC_PMAC 19 20 int pmac_done(pmac_state *state, unsigned char *out, unsigned long *outlen) 21 { 22 int err, x; 23 24 LTC_ARGCHK(state != NULL); 25 LTC_ARGCHK(out != NULL); 26 if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) { 27 return err; 28 } 29 30 if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) || 31 (state->block_len > (int)sizeof(state->block)) || (state->buflen > state->block_len)) { 32 return CRYPT_INVALID_ARG; 33 } 34 35 36 /* handle padding. If multiple xor in L/x */ 37 38 if (state->buflen == state->block_len) { 39 /* xor Lr against the checksum */ 40 for (x = 0; x < state->block_len; x++) { 41 state->checksum[x] ^= state->block[x] ^ state->Lr[x]; 42 } 43 } else { 44 /* otherwise xor message bytes then the 0x80 byte */ 45 for (x = 0; x < state->buflen; x++) { 46 state->checksum[x] ^= state->block[x]; 47 } 48 state->checksum[x] ^= 0x80; 49 } 50 51 /* encrypt it */ 52 if ((err = cipher_descriptor[state->cipher_idx].ecb_encrypt(state->checksum, state->checksum, &state->key)) != CRYPT_OK) { 53 return err; 54 } 55 cipher_descriptor[state->cipher_idx].done(&state->key); 56 57 /* store it */ 58 for (x = 0; x < state->block_len && x < (int)*outlen; x++) { 59 out[x] = state->checksum[x]; 60 } 61 *outlen = x; 62 63 #ifdef LTC_CLEAN_STACK 64 zeromem(state, sizeof(*state)); 65 #endif 66 return CRYPT_OK; 67 } 68 69 #endif 70 71 72 /* $Source: /cvs/libtom/libtomcrypt/src/mac/pmac/pmac_done.c,v $ */ 73 /* $Revision: 1.8 $ */ 74 /* $Date: 2006/11/03 00:39:49 $ */ 75
