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 12f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/** 13f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @file ocb_encrypt.c 14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project OCB implementation, encrypt data, by Tom St Denis 15f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/ 16f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include "tomcrypt.h" 17f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 18f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef OCB_MODE 19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/** 21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project Encrypt a block of data with OCB. 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ocb The OCB state 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param pt The plaintext (length of the block size of the block cipher) 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ct [out] The ciphertext (same size as the pt) 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @return CRYPT_OK if successful 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/ 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint ocb_encrypt(ocb_state *ocb, const unsigned char *pt, unsigned char *ct) 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project unsigned char Z[MAXBLOCKSIZE], tmp[MAXBLOCKSIZE]; 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int err, x; 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(ocb != NULL); 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(pt != NULL); 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(ct != NULL); 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = cipher_is_valid(ocb->cipher)) != CRYPT_OK) { 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (ocb->block_len != cipher_descriptor[ocb->cipher].block_length) { 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return CRYPT_INVALID_ARG; 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* compute checksum */ 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (x = 0; x < ocb->block_len; x++) { 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ocb->checksum[x] ^= pt[x]; 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* Get Z[i] value */ 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ocb_shift_xor(ocb, Z); 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* xor pt in, encrypt, xor Z out */ 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (x = 0; x < ocb->block_len; x++) { 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project tmp[x] = pt[x] ^ Z[x]; 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = cipher_descriptor[ocb->cipher].ecb_encrypt(tmp, ct, &ocb->key)) != CRYPT_OK) { 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (x = 0; x < ocb->block_len; x++) { 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ct[x] ^= Z[x]; 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef LTC_CLEAN_STACK 62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project zeromem(Z, sizeof(Z)); 63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project zeromem(tmp, sizeof(tmp)); 64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return CRYPT_OK; 66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 67f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 68f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 69f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 70f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_encrypt.c,v $ */ 71f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.5 $ */ 72f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/03/31 14:15:35 $ */ 73