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Diffstat (limited to 'core/lib/libtomcrypt/src/modes/xts/xts_encrypt.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/modes/xts/xts_encrypt.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/modes/xts/xts_encrypt.c b/core/lib/libtomcrypt/src/modes/xts/xts_encrypt.c new file mode 100644 index 0000000..3448383 --- /dev/null +++ b/core/lib/libtomcrypt/src/modes/xts/xts_encrypt.c @@ -0,0 +1,189 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtom.org + */ +#include "tomcrypt.h" + +/** + Source donated by Elliptic Semiconductor Inc (www.ellipticsemi.com) to the LibTom Projects +*/ + +#ifdef LTC_XTS_MODE + +static int tweak_crypt(const unsigned char *P, unsigned char *C, unsigned char *T, symmetric_xts *xts) +{ + unsigned long x; + int err; + + /* tweak encrypt block i */ +#ifdef LTC_FAST + for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)&C[x]) = *((LTC_FAST_TYPE*)&P[x]) ^ *((LTC_FAST_TYPE*)&T[x]); + } +#else + for (x = 0; x < 16; x++) { + C[x] = P[x] ^ T[x]; + } +#endif + + if ((err = cipher_descriptor[xts->cipher]->ecb_encrypt(C, C, &xts->key1)) != CRYPT_OK) { + return err; + } + +#ifdef LTC_FAST + for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)&C[x]) ^= *((LTC_FAST_TYPE*)&T[x]); + } +#else + for (x = 0; x < 16; x++) { + C[x] = C[x] ^ T[x]; + } +#endif + + /* LFSR the tweak */ + xts_mult_x(T); + + return CRYPT_OK; +} + +/** XTS Encryption + @param pt [in] Plaintext + @param ptlen Length of plaintext (and ciphertext) + @param ct [out] Ciphertext + @param tweak [in] The 128--bit encryption tweak (e.g. sector number) + @param xts The XTS structure + Returns CRYPT_OK upon success +*/ +int xts_encrypt(const unsigned char *pt, unsigned long ptlen, unsigned char *ct, unsigned char *tweak, + symmetric_xts *xts) +{ + const struct ltc_cipher_descriptor *desc; + unsigned char PP[16], CC[16], T[16]; + unsigned long i, m, mo, lim; + int err; + + /* check inputs */ + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LTC_ARGCHK(tweak != NULL); + LTC_ARGCHK(xts != NULL); + + /* check if valid */ + if ((err = cipher_is_valid(xts->cipher)) != CRYPT_OK) { + return err; + } + + /* get number of blocks */ + m = ptlen >> 4; + mo = ptlen & 15; + + /* must have at least one full block */ + if (m == 0) { + return CRYPT_INVALID_ARG; + } + + if (mo == 0) { + lim = m; + } else { + lim = m - 1; + } + + desc = cipher_descriptor[xts->cipher]; + + if (desc->accel_xts_encrypt && lim > 0) { + + /* use accelerated encryption for whole blocks */ + if ((err = desc->accel_xts_encrypt(pt, ct, lim, tweak, &xts->key1, + &xts->key2) != CRYPT_OK)) { + return err; + } + ct += lim * 16; + pt += lim * 16; + + /* tweak is encrypted on output */ + XMEMCPY(T, tweak, sizeof(T)); + } else { + + /* encrypt the tweak */ + if ((err = desc->ecb_encrypt(tweak, T, &xts->key2)) != CRYPT_OK) { + return err; + } + + for (i = 0; i < lim; i++) { + if ((err = tweak_crypt(pt, ct, T, xts)) != CRYPT_OK) { + return err; + } + ct += 16; + pt += 16; + } + } + + /* if ptlen not divide 16 then */ + if (mo > 0) { + /* CC = tweak encrypt block m-1 */ + if ((err = tweak_crypt(pt, CC, T, xts)) != CRYPT_OK) { + return err; + } + + /* Cm = first ptlen % 16 bytes of CC */ + for (i = 0; i < mo; i++) { + PP[i] = pt[16+i]; + ct[16+i] = CC[i]; + } + + for (; i < 16; i++) { + PP[i] = CC[i]; + } + + /* Cm-1 = Tweak encrypt PP */ + if ((err = tweak_crypt(PP, ct, T, xts)) != CRYPT_OK) { + return err; + } + } + + /* Decrypt the tweak back */ + if ((err = cipher_descriptor[xts->cipher]->ecb_decrypt(T, tweak, &xts->key2)) != CRYPT_OK) { + return err; + } + + return err; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/modes/xts/xts_encrypt.c,v $ */ +/* $Revision: 1.5 $ */ +/* $Date: 2007/05/12 14:05:56 $ */ |