1f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* LibTomCrypt, modular cryptographic library -- Tom St Denis 2f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 3f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * LibTomCrypt is a library that provides various cryptographic 4f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * algorithms in a highly modular and flexible manner. 5f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 6f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library is free for all purposes without any express 7f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * guarantee it works. 8f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 9f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com 10f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */ 11f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include "tomcrypt.h" 12f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 13f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/** 14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @file ofb_start.c 15f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project OFB implementation, start chain, Tom St Denis 16f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/ 17f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 18f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef LTC_OFB_MODE 20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/** 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project Initialize a OFB context 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param cipher The index of the cipher desired 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param IV The initial vector 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param key The secret key 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param keylen The length of the secret key (octets) 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param num_rounds Number of rounds in the cipher desired (0 for default) 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ofb The OFB state to initialize 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @return CRYPT_OK if successful 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/ 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint ofb_start(int cipher, const unsigned char *IV, const unsigned char *key, 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int keylen, int num_rounds, symmetric_OFB *ofb) 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int x, err; 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(IV != NULL); 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(key != NULL); 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(ofb != NULL); 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* copy details */ 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ofb->cipher = cipher; 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ofb->blocklen = cipher_descriptor[cipher].block_length; 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (x = 0; x < ofb->blocklen; x++) { 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ofb->IV[x] = IV[x]; 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* init the cipher */ 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ofb->padlen = ofb->blocklen; 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return cipher_descriptor[cipher].setup(key, keylen, num_rounds, &ofb->key); 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtomcrypt/src/modes/ofb/ofb_start.c,v $ */ 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.5 $ */ 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/06/29 01:51:34 $ */ 61