345 lines
10 KiB
C
345 lines
10 KiB
C
/* rfc2268.c - The cipher described in rfc2268; aka Ron's Cipher 2.
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* Copyright (C) 2003 Nikos Mavroyanopoulos
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* Copyright (C) 2004 Free Software Foundation, Inc.
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*
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* This file is part of Libgcrypt
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*
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* Libgcrypt is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser general Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* Libgcrypt is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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/* This implementation was written by Nikos Mavroyanopoulos for GNUTLS
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* as a Libgcrypt module (gnutls/lib/x509/rc2.c) and later adapted for
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* direct use by Libgcrypt by Werner Koch. This implementation is
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* only useful for pkcs#12 descryption.
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*
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* The implementation here is based on Peter Gutmann's RRC.2 paper.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "g10lib.h"
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#include "types.h"
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#include "cipher.h"
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#define RFC2268_BLOCKSIZE 8
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typedef struct
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{
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u16 S[64];
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} RFC2268_context;
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static const unsigned char rfc2268_sbox[] = {
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217, 120, 249, 196, 25, 221, 181, 237,
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40, 233, 253, 121, 74, 160, 216, 157,
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198, 126, 55, 131, 43, 118, 83, 142,
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98, 76, 100, 136, 68, 139, 251, 162,
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23, 154, 89, 245, 135, 179, 79, 19,
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97, 69, 109, 141, 9, 129, 125, 50,
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189, 143, 64, 235, 134, 183, 123, 11,
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240, 149, 33, 34, 92, 107, 78, 130,
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84, 214, 101, 147, 206, 96, 178, 28,
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115, 86, 192, 20, 167, 140, 241, 220,
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18, 117, 202, 31, 59, 190, 228, 209,
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66, 61, 212, 48, 163, 60, 182, 38,
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111, 191, 14, 218, 70, 105, 7, 87,
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39, 242, 29, 155, 188, 148, 67, 3,
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248, 17, 199, 246, 144, 239, 62, 231,
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6, 195, 213, 47, 200, 102, 30, 215,
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8, 232, 234, 222, 128, 82, 238, 247,
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132, 170, 114, 172, 53, 77, 106, 42,
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150, 26, 210, 113, 90, 21, 73, 116,
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75, 159, 208, 94, 4, 24, 164, 236,
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194, 224, 65, 110, 15, 81, 203, 204,
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36, 145, 175, 80, 161, 244, 112, 57,
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153, 124, 58, 133, 35, 184, 180, 122,
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252, 2, 54, 91, 37, 85, 151, 49,
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45, 93, 250, 152, 227, 138, 146, 174,
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5, 223, 41, 16, 103, 108, 186, 201,
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211, 0, 230, 207, 225, 158, 168, 44,
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99, 22, 1, 63, 88, 226, 137, 169,
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13, 56, 52, 27, 171, 51, 255, 176,
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187, 72, 12, 95, 185, 177, 205, 46,
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197, 243, 219, 71, 229, 165, 156, 119,
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10, 166, 32, 104, 254, 127, 193, 173
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};
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#define rotl16(x,n) (((x) << ((u16)(n))) | ((x) >> (16 - (u16)(n))))
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#define rotr16(x,n) (((x) >> ((u16)(n))) | ((x) << (16 - (u16)(n))))
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static const char *selftest (void);
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static void
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do_encrypt (void *context, unsigned char *outbuf, const unsigned char *inbuf)
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{
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RFC2268_context *ctx = context;
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register int i, j;
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u16 word0 = 0, word1 = 0, word2 = 0, word3 = 0;
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word0 = (word0 << 8) | inbuf[1];
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word0 = (word0 << 8) | inbuf[0];
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word1 = (word1 << 8) | inbuf[3];
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word1 = (word1 << 8) | inbuf[2];
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word2 = (word2 << 8) | inbuf[5];
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word2 = (word2 << 8) | inbuf[4];
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word3 = (word3 << 8) | inbuf[7];
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word3 = (word3 << 8) | inbuf[6];
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for (i = 0; i < 16; i++)
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{
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j = i * 4;
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/* For some reason I cannot combine those steps. */
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word0 += (word1 & ~word3) + (word2 & word3) + ctx->S[j];
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word0 = rotl16(word0, 1);
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word1 += (word2 & ~word0) + (word3 & word0) + ctx->S[j + 1];
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word1 = rotl16(word1, 2);
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word2 += (word3 & ~word1) + (word0 & word1) + ctx->S[j + 2];
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word2 = rotl16(word2, 3);
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word3 += (word0 & ~word2) + (word1 & word2) + ctx->S[j + 3];
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word3 = rotl16(word3, 5);
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if (i == 4 || i == 10)
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{
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word0 += ctx->S[word3 & 63];
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word1 += ctx->S[word0 & 63];
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word2 += ctx->S[word1 & 63];
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word3 += ctx->S[word2 & 63];
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}
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}
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outbuf[0] = word0 & 255;
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outbuf[1] = word0 >> 8;
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outbuf[2] = word1 & 255;
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outbuf[3] = word1 >> 8;
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outbuf[4] = word2 & 255;
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outbuf[5] = word2 >> 8;
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outbuf[6] = word3 & 255;
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outbuf[7] = word3 >> 8;
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}
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static void
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do_decrypt (void *context, unsigned char *outbuf, const unsigned char *inbuf)
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{
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RFC2268_context *ctx = context;
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register int i, j;
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u16 word0 = 0, word1 = 0, word2 = 0, word3 = 0;
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word0 = (word0 << 8) | inbuf[1];
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word0 = (word0 << 8) | inbuf[0];
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word1 = (word1 << 8) | inbuf[3];
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word1 = (word1 << 8) | inbuf[2];
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word2 = (word2 << 8) | inbuf[5];
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word2 = (word2 << 8) | inbuf[4];
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word3 = (word3 << 8) | inbuf[7];
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word3 = (word3 << 8) | inbuf[6];
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for (i = 15; i >= 0; i--)
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{
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j = i * 4;
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word3 = rotr16(word3, 5);
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word3 -= (word0 & ~word2) + (word1 & word2) + ctx->S[j + 3];
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word2 = rotr16(word2, 3);
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word2 -= (word3 & ~word1) + (word0 & word1) + ctx->S[j + 2];
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word1 = rotr16(word1, 2);
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word1 -= (word2 & ~word0) + (word3 & word0) + ctx->S[j + 1];
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word0 = rotr16(word0, 1);
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word0 -= (word1 & ~word3) + (word2 & word3) + ctx->S[j];
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if (i == 5 || i == 11)
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{
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word3 = word3 - ctx->S[word2 & 63];
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word2 = word2 - ctx->S[word1 & 63];
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word1 = word1 - ctx->S[word0 & 63];
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word0 = word0 - ctx->S[word3 & 63];
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}
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}
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outbuf[0] = word0 & 255;
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outbuf[1] = word0 >> 8;
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outbuf[2] = word1 & 255;
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outbuf[3] = word1 >> 8;
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outbuf[4] = word2 & 255;
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outbuf[5] = word2 >> 8;
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outbuf[6] = word3 & 255;
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outbuf[7] = word3 >> 8;
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}
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static gpg_err_code_t
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setkey_core (void *context, const unsigned char *key, unsigned int keylen, int with_phase2)
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{
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static int initialized;
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static const char *selftest_failed;
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RFC2268_context *ctx = context;
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unsigned int i;
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unsigned char *S, x;
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int len;
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int bits = keylen * 8;
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if (!initialized)
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{
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initialized = 1;
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selftest_failed = selftest ();
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if (selftest_failed)
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log_error ("RFC2268 selftest failed (%s).\n", selftest_failed);
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}
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if (selftest_failed)
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return GPG_ERR_SELFTEST_FAILED;
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if (keylen < 40 / 8) /* We want at least 40 bits. */
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return GPG_ERR_INV_KEYLEN;
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S = (unsigned char *) ctx->S;
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for (i = 0; i < keylen; i++)
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S[i] = key[i];
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for (i = keylen; i < 128; i++)
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S[i] = rfc2268_sbox[(S[i - keylen] + S[i - 1]) & 255];
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S[0] = rfc2268_sbox[S[0]];
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/* Phase 2 - reduce effective key size to "bits". This was not
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* discussed in Gutmann's paper. I've copied that from the public
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* domain code posted in sci.crypt. */
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if (with_phase2)
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{
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len = (bits + 7) >> 3;
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i = 128 - len;
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x = rfc2268_sbox[S[i] & (255 >> (7 & -bits))];
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S[i] = x;
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while (i--)
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{
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x = rfc2268_sbox[x ^ S[i + len]];
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S[i] = x;
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}
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}
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/* Make the expanded key, endian independent. */
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for (i = 0; i < 64; i++)
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ctx->S[i] = ( (u16) S[i * 2] | (((u16) S[i * 2 + 1]) << 8));
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return 0;
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}
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static gpg_err_code_t
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do_setkey (void *context, const unsigned char *key, unsigned int keylen)
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{
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return setkey_core (context, key, keylen, 1);
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}
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static const char *
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selftest (void)
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{
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RFC2268_context ctx;
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unsigned char scratch[16];
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/* Test vectors from Peter Gutmann's paper. */
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static unsigned char key_1[] =
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static unsigned char plaintext_1[] =
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
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static const unsigned char ciphertext_1[] =
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{ 0x1C, 0x19, 0x8A, 0x83, 0x8D, 0xF0, 0x28, 0xB7 };
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static unsigned char key_2[] =
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{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
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};
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static unsigned char plaintext_2[] =
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
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static unsigned char ciphertext_2[] =
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{ 0x50, 0xDC, 0x01, 0x62, 0xBD, 0x75, 0x7F, 0x31 };
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/* This one was checked against libmcrypt's RFC2268. */
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static unsigned char key_3[] =
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{ 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static unsigned char plaintext_3[] =
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{ 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
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static unsigned char ciphertext_3[] =
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{ 0x8f, 0xd1, 0x03, 0x89, 0x33, 0x6b, 0xf9, 0x5e };
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/* First test. */
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setkey_core (&ctx, key_1, sizeof(key_1), 0);
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do_encrypt (&ctx, scratch, plaintext_1);
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if (memcmp (scratch, ciphertext_1, sizeof(ciphertext_1)))
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return "RFC2268 encryption test 1 failed.";
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setkey_core (&ctx, key_1, sizeof(key_1), 0);
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do_decrypt (&ctx, scratch, scratch);
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if (memcmp (scratch, plaintext_1, sizeof(plaintext_1)))
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return "RFC2268 decryption test 1 failed.";
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/* Second test. */
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setkey_core (&ctx, key_2, sizeof(key_2), 0);
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do_encrypt (&ctx, scratch, plaintext_2);
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if (memcmp (scratch, ciphertext_2, sizeof(ciphertext_2)))
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return "RFC2268 encryption test 2 failed.";
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setkey_core (&ctx, key_2, sizeof(key_2), 0);
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do_decrypt (&ctx, scratch, scratch);
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if (memcmp (scratch, plaintext_2, sizeof(plaintext_2)))
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return "RFC2268 decryption test 2 failed.";
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/* Third test. */
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setkey_core(&ctx, key_3, sizeof(key_3), 0);
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do_encrypt(&ctx, scratch, plaintext_3);
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if (memcmp(scratch, ciphertext_3, sizeof(ciphertext_3)))
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return "RFC2268 encryption test 3 failed.";
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setkey_core (&ctx, key_3, sizeof(key_3), 0);
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do_decrypt (&ctx, scratch, scratch);
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if (memcmp(scratch, plaintext_3, sizeof(plaintext_3)))
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return "RFC2268 decryption test 3 failed.";
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return NULL;
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}
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static gcry_cipher_oid_spec_t oids_rfc2268_40[] =
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{
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/*{ "1.2.840.113549.3.2", GCRY_CIPHER_MODE_CBC },*/
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/* pbeWithSHAAnd40BitRC2_CBC */
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{ "1.2.840.113549.1.12.1.6", GCRY_CIPHER_MODE_CBC },
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{ NULL }
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};
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gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_40 = {
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"RFC2268_40", NULL, oids_rfc2268_40,
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RFC2268_BLOCKSIZE, 40, sizeof(RFC2268_context),
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do_setkey, do_encrypt, do_decrypt
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};
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