pcompress/crypto/scrypt/crypto_aesctr.c

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/*
* This file is a part of Pcompress, a chunked parallel multi-
* algorithm lossless compression and decompression program.
*
* Copyright (C) 2012 Moinak Ghosh. All rights reserved.
* Use is subject to license terms.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* moinakg@belenix.org, http://moinakg.wordpress.com/
*/
/*-
* Copyright 2007-2009 Colin Percival
* 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 AUTHOR 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 AUTHOR 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.
*
* This file was originally written by Colin Percival as part of the Tarsnap
* online backup system.
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
#ifdef __USE_SSE_INTRIN__
#include <emmintrin.h>
#endif
#include <utils.h>
#include "crypto_aesctr.h"
extern setkey_func_ptr enc_setkey;
extern encrypt_func_ptr enc_encrypt;
struct crypto_aesctr {
AES_KEY * key;
uint64_t nonce;
uint64_t bytectr;
uint8_t buf[16] __attribute__((aligned(16)));
};
/**
* crypto_aesctr_init(key, nonce):
* Prepare to encrypt/decrypt data with AES in CTR mode, using the provided
* expanded key and nonce. The key provided must remain valid for the
* lifetime of the stream.
*/
struct crypto_aesctr *
crypto_aesctr_init(AES_KEY * key, uint64_t nonce)
{
struct crypto_aesctr * stream;
/* Allocate memory. */
if ((stream = (struct crypto_aesctr *)malloc(sizeof(struct crypto_aesctr))) == NULL)
goto err0;
/* Initialize values. */
stream->key = key;
stream->nonce = nonce;
stream->bytectr = 0;
/* Success! */
return (stream);
err0:
/* Failure! */
return (NULL);
}
/**
* crypto_aesctr_stream(stream, inbuf, outbuf, buflen):
* Generate the next ${buflen} bytes of the AES-CTR stream and xor them with
* bytes from ${inbuf}, writing the result into ${outbuf}. If the buffers
* ${inbuf} and ${outbuf} overlap, they must be identical.
*/
void
crypto_aesctr_stream(struct crypto_aesctr * stream, const uint8_t * inbuf,
uint8_t * outbuf, size_t buflen)
{
uint8_t pblk[16];
size_t pos;
int bytemod, last;
last = 0;
pos = 0;
*((uint64_t *)pblk) = htonll(stream->nonce);
do_last:
for (; pos < buflen; pos++) {
/* How far through the buffer are we? */
bytemod = stream->bytectr & (16 - 1);
/* Generate a block of cipherstream if needed. */
if (bytemod == 0) {
*((uint64_t *)(pblk + 8)) = htonll(stream->bytectr / 16);
enc_encrypt(pblk, stream->buf, stream->key);
#ifdef __USE_SSE_INTRIN__
if (!last)
break;
#endif
}
/* Encrypt a byte. */
outbuf[pos] = inbuf[pos] ^ stream->buf[bytemod];
/* Move to the next byte of cipherstream. */
stream->bytectr += 1;
}
#ifdef __USE_SSE_INTRIN__
if (last) {
memset(pblk, 0, 16);
return;
}
for (; pos < buflen-15; pos += 16) {
__m128i cblk, dat, odat;
PREFETCH_WRITE(outbuf+pos, 0);
PREFETCH_READ(inbuf+pos, 0);
cblk = _mm_load_si128((__m128i *)(stream->buf));
dat = _mm_loadu_si128((__m128i *)(inbuf+pos));
odat = _mm_xor_si128(cblk, dat);
_mm_storeu_si128((__m128i *)(outbuf+pos), odat);
stream->bytectr += 16;
*((uint64_t *)(pblk + 8)) = htonll(stream->bytectr / 16);
enc_encrypt(pblk, stream->buf, stream->key);
}
last = 1;
goto do_last;
#endif
}
/**
* crypto_aesctr_free(stream):
* Free the provided stream object.
*/
void
crypto_aesctr_free(struct crypto_aesctr * stream)
{
int i;
/* Zero potentially sensitive information. */
for (i = 0; i < 16; i++)
stream->buf[i] = 0;
stream->bytectr = stream->nonce = 0;
/* Free the stream. */
free(stream);
}