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_done_decrypt.c 14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project OCB implementation, terminate decryption, 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 Terminate a decrypting OCB state 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ocb The OCB state 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ct The ciphertext (if any) 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param ctlen The length of the ciphertext (octets) 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param pt [out] The plaintext 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param tag The authentication tag (to compare against) 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param taglen The length of the authentication tag provided 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @param stat [out] The result of the tag comparison 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project @return CRYPT_OK if the process was successful regardless if the tag is valid 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/ 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint ocb_done_decrypt(ocb_state *ocb, 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project const unsigned char *ct, unsigned long ctlen, 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project unsigned char *pt, 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project const unsigned char *tag, unsigned long taglen, int *stat) 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int err; 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project unsigned char *tagbuf; 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project unsigned long tagbuflen; 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(ocb != NULL); 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(pt != NULL); 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(ct != NULL); 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(tag != NULL); 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project LTC_ARGCHK(stat != NULL); 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* default to failed */ 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *stat = 0; 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* allocate memory */ 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project tagbuf = XMALLOC(MAXBLOCKSIZE); 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (tagbuf == NULL) { 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return CRYPT_MEM; 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project tagbuflen = MAXBLOCKSIZE; 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((err = s_ocb_done(ocb, ct, ctlen, pt, tagbuf, &tagbuflen, 1)) != CRYPT_OK) { 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project goto LBL_ERR; 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (taglen <= tagbuflen && XMEMCMP(tagbuf, tag, taglen) == 0) { 61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *stat = 1; 62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project err = CRYPT_OK; 65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source ProjectLBL_ERR: 66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef LTC_CLEAN_STACK 67f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project zeromem(tagbuf, MAXBLOCKSIZE); 68f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 69f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 70f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project XFREE(tagbuf); 71f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 72f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return err; 73f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 74f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 75f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 76f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 77f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 78f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_done_decrypt.c,v $ */ 79f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.5 $ */ 80f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/11/01 09:28:17 $ */ 81