mirror of
https://github.com/guanzhi/GmSSL.git
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118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
/*
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* Copyright (c) 2014 - 2020 The GmSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the GmSSL Project.
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* (http://gmssl.org/)"
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*
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* 4. The name "GmSSL Project" must not be used to endorse or promote
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* products derived from this software without prior written
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* permission. For written permission, please contact
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* guanzhi1980@gmail.com.
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*
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* 5. Products derived from this software may not be called "GmSSL"
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* nor may "GmSSL" appear in their names without prior written
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* permission of the GmSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the GmSSL Project
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* (http://gmssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE GmSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE GmSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <gmssl/rc4.h>
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void rc4_init(RC4_STATE *state, const uint8_t *key, size_t keylen)
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{
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int i, j;
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uint8_t *s = state->d;
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uint8_t k[256];
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uint8_t temp;
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/* expand key */
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for (i = 0; i < keylen; i++) {
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k[i] = key[i];
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}
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for (i = keylen; i < 256; i++) {
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k[i] = key[i % keylen];
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}
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/* init state */
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for (i = 0; i < 256; i++) {
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s[i] = i;
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}
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/* shuffle state with key */
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j = 0;
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for (i = 0; i < 256; i++) {
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j = (j + s[i] + k[i]) % 256;
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/* swap(s[i], s[j]) */
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temp = s[j];
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s[j] = s[i];
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s[i] = temp;
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}
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/* clean expanded temp key */
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memset(k, 0, sizeof(k));
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}
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void rc4_generate_keystream(RC4_STATE *state, size_t outlen, uint8_t *out)
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{
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int i = 0, j = 0;
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uint8_t *s = state->d;
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int oi;
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int temp;
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while (outlen > 0) {
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i = (i + 1) % 256;
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j = (j + s[i]) % 256;
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/* swap(s[i], s[j]) */
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temp = s[j];
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s[j] = s[i];
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s[i] = temp;
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oi = (s[i] + s[j]) % 256;
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*out++ = s[oi];
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outlen--;
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}
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}
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uint8_t rc4_generate_keybyte(RC4_STATE *state)
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{
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uint8_t out[1];
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rc4_generate_keystream(state, 1, out);
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return out[0];
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}
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