openssl/crypto/seed/seed_cbc.c

/* crypto/seed/seed_cbc.c -*- mode:C; c-file-style: "eay" -*- */
/* ====================================================================
 * Copyright (c) 1998-2007 The OpenSSL Project.  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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
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 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * 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.
 * ====================================================================
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 */

#include "seed_locl.h"
#include <string.h>

void SEED_cbc_encrypt(const unsigned char *in, unsigned char *out,
                      size_t len, const SEED_KEY_SCHEDULE *ks,
                      unsigned char ivec[SEED_BLOCK_SIZE], int enc)
{
    size_t n;
    unsigned char tmp[SEED_BLOCK_SIZE];
    const unsigned char *iv = ivec;

    if (enc) {
        while (len >= SEED_BLOCK_SIZE) {
            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
                out[n] = in[n] ^ iv[n];
            SEED_encrypt(out, out, ks);
            iv = out;
            len -= SEED_BLOCK_SIZE;
            in += SEED_BLOCK_SIZE;
            out += SEED_BLOCK_SIZE;
        }
        if (len) {
            for (n = 0; n < len; ++n)
                out[n] = in[n] ^ iv[n];
            for (n = len; n < SEED_BLOCK_SIZE; ++n)
                out[n] = iv[n];
            SEED_encrypt(out, out, ks);
            iv = out;
        }
        memcpy(ivec, iv, SEED_BLOCK_SIZE);
    } else if (in != out) {     /* decrypt */
        while (len >= SEED_BLOCK_SIZE) {
            SEED_decrypt(in, out, ks);
            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
                out[n] ^= iv[n];
            iv = in;
            len -= SEED_BLOCK_SIZE;
            in += SEED_BLOCK_SIZE;
            out += SEED_BLOCK_SIZE;
        }
        if (len) {
            SEED_decrypt(in, tmp, ks);
            for (n = 0; n < len; ++n)
                out[n] = tmp[n] ^ iv[n];
            iv = in;
        }
        memcpy(ivec, iv, SEED_BLOCK_SIZE);
    } else {                    /* decrypt, overlap */

        while (len >= SEED_BLOCK_SIZE) {
            memcpy(tmp, in, SEED_BLOCK_SIZE);
            SEED_decrypt(in, out, ks);
            for (n = 0; n < SEED_BLOCK_SIZE; ++n)
                out[n] ^= ivec[n];
            memcpy(ivec, tmp, SEED_BLOCK_SIZE);
            len -= SEED_BLOCK_SIZE;
            in += SEED_BLOCK_SIZE;
            out += SEED_BLOCK_SIZE;
        }
        if (len) {
            memcpy(tmp, in, SEED_BLOCK_SIZE);
            SEED_decrypt(tmp, tmp, ks);
            for (n = 0; n < len; ++n)
                out[n] = tmp[n] ^ ivec[n];
            memcpy(ivec, tmp, SEED_BLOCK_SIZE);
        }
    }
}