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1acab96d97
Add an implementation of RC4. This will be used by Rockchip booting but may be useful in other situations. Signed-off-by: Simon Glass <sjg@chromium.org>
50 lines
825 B
C
50 lines
825 B
C
/*
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* (C) Copyright 2015 Google, Inc
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*
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* (C) Copyright 2008-2014 Rockchip Electronics
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*
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* Rivest Cipher 4 (RC4) implementation
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef USE_HOSTCC
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#include <common.h>
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#endif
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#include <rc4.h>
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void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
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{
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unsigned char s[256], k[256], temp;
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unsigned short i, j, t;
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int ptr;
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j = 0;
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for (i = 0; i < 256; i++) {
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s[i] = (unsigned char)i;
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j &= 0x0f;
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k[i] = key[j];
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j++;
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}
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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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temp = s[i];
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s[i] = s[j];
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s[j] = temp;
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}
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i = 0;
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j = 0;
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for (ptr = 0; ptr < len; ptr++) {
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i = (i + 1) % 256;
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j = (j + s[i]) % 256;
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temp = s[i];
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s[i] = s[j];
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s[j] = temp;
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t = (s[i] + (s[j] % 256)) % 256;
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buf[ptr] = buf[ptr] ^ s[t];
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}
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}
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