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rfc2268.c
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/* rfc2268.c - The cipher described in rfc2268; aka Ron's Cipher 2.
* Copyright (C) 2003 Nikos Mavroyanopoulos
* Copyright (C) 2004 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt
*
* Libgcrypt 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 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, see <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
/* This implementation was written by Nikos Mavroyanopoulos for GNUTLS
* as a Libgcrypt module (gnutls/lib/x509/rc2.c) and later adapted for
* direct use by Libgcrypt by Werner Koch. This implementation is
* only useful for pkcs#12 decryption.
*
* The implementation here is based on Peter Gutmann's RRC.2 paper.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "g10lib.h"
#include "types.h"
#include "cipher.h"
#include "cipher-internal.h"
#define RFC2268_BLOCKSIZE 8
typedef struct
{
u16 S[64];
} RFC2268_context;
static const unsigned char rfc2268_sbox[] = {
217, 120, 249, 196, 25, 221, 181, 237,
40, 233, 253, 121, 74, 160, 216, 157,
198, 126, 55, 131, 43, 118, 83, 142,
98, 76, 100, 136, 68, 139, 251, 162,
23, 154, 89, 245, 135, 179, 79, 19,
97, 69, 109, 141, 9, 129, 125, 50,
189, 143, 64, 235, 134, 183, 123, 11,
240, 149, 33, 34, 92, 107, 78, 130,
84, 214, 101, 147, 206, 96, 178, 28,
115, 86, 192, 20, 167, 140, 241, 220,
18, 117, 202, 31, 59, 190, 228, 209,
66, 61, 212, 48, 163, 60, 182, 38,
111, 191, 14, 218, 70, 105, 7, 87,
39, 242, 29, 155, 188, 148, 67, 3,
248, 17, 199, 246, 144, 239, 62, 231,
6, 195, 213, 47, 200, 102, 30, 215,
8, 232, 234, 222, 128, 82, 238, 247,
132, 170, 114, 172, 53, 77, 106, 42,
150, 26, 210, 113, 90, 21, 73, 116,
75, 159, 208, 94, 4, 24, 164, 236,
194, 224, 65, 110, 15, 81, 203, 204,
36, 145, 175, 80, 161, 244, 112, 57,
153, 124, 58, 133, 35, 184, 180, 122,
252, 2, 54, 91, 37, 85, 151, 49,
45, 93, 250, 152, 227, 138, 146, 174,
5, 223, 41, 16, 103, 108, 186, 201,
211, 0, 230, 207, 225, 158, 168, 44,
99, 22, 1, 63, 88, 226, 137, 169,
13, 56, 52, 27, 171, 51, 255, 176,
187, 72, 12, 95, 185, 177, 205, 46,
197, 243, 219, 71, 229, 165, 156, 119,
10, 166, 32, 104, 254, 127, 193, 173
};
#define rotl16(x,n) (((x) << ((u16)(n))) | ((x) >> (16 - (u16)(n))))
#define rotr16(x,n) (((x) >> ((u16)(n))) | ((x) << (16 - (u16)(n))))
static const char *selftest (void);
static void
do_encrypt (void *context, unsigned char *outbuf, const unsigned char *inbuf)
{
RFC2268_context *ctx = context;
register int i, j;
u16 word0 = 0, word1 = 0, word2 = 0, word3 = 0;
word0 = (word0 << 8) | inbuf[1];
word0 = (word0 << 8) | inbuf[0];
word1 = (word1 << 8) | inbuf[3];
word1 = (word1 << 8) | inbuf[2];
word2 = (word2 << 8) | inbuf[5];
word2 = (word2 << 8) | inbuf[4];
word3 = (word3 << 8) | inbuf[7];
word3 = (word3 << 8) | inbuf[6];
for (i = 0; i < 16; i++)
{
j = i * 4;
/* For some reason I cannot combine those steps. */
word0 += (word1 & ~word3) + (word2 & word3) + ctx->S[j];
word0 = rotl16(word0, 1);
word1 += (word2 & ~word0) + (word3 & word0) + ctx->S[j + 1];
word1 = rotl16(word1, 2);
word2 += (word3 & ~word1) + (word0 & word1) + ctx->S[j + 2];
word2 = rotl16(word2, 3);
word3 += (word0 & ~word2) + (word1 & word2) + ctx->S[j + 3];
word3 = rotl16(word3, 5);
if (i == 4 || i == 10)
{
word0 += ctx->S[word3 & 63];
word1 += ctx->S[word0 & 63];
word2 += ctx->S[word1 & 63];
word3 += ctx->S[word2 & 63];
}
}
outbuf[0] = word0 & 255;
outbuf[1] = word0 >> 8;
outbuf[2] = word1 & 255;
outbuf[3] = word1 >> 8;
outbuf[4] = word2 & 255;
outbuf[5] = word2 >> 8;
outbuf[6] = word3 & 255;
outbuf[7] = word3 >> 8;
}
static unsigned int
encrypt_block (void *context, unsigned char *outbuf, const unsigned char *inbuf)
{
do_encrypt (context, outbuf, inbuf);
return /*burn_stack*/ (4 * sizeof(void *) + sizeof(void *) + sizeof(u32) * 4);
}
static void
do_decrypt (void *context, unsigned char *outbuf, const unsigned char *inbuf)
{
RFC2268_context *ctx = context;
register int i, j;
u16 word0 = 0, word1 = 0, word2 = 0, word3 = 0;
word0 = (word0 << 8) | inbuf[1];
word0 = (word0 << 8) | inbuf[0];
word1 = (word1 << 8) | inbuf[3];
word1 = (word1 << 8) | inbuf[2];
word2 = (word2 << 8) | inbuf[5];
word2 = (word2 << 8) | inbuf[4];
word3 = (word3 << 8) | inbuf[7];
word3 = (word3 << 8) | inbuf[6];
for (i = 15; i >= 0; i--)
{
j = i * 4;
word3 = rotr16(word3, 5);
word3 -= (word0 & ~word2) + (word1 & word2) + ctx->S[j + 3];
word2 = rotr16(word2, 3);
word2 -= (word3 & ~word1) + (word0 & word1) + ctx->S[j + 2];
word1 = rotr16(word1, 2);
word1 -= (word2 & ~word0) + (word3 & word0) + ctx->S[j + 1];
word0 = rotr16(word0, 1);
word0 -= (word1 & ~word3) + (word2 & word3) + ctx->S[j];
if (i == 5 || i == 11)
{
word3 = word3 - ctx->S[word2 & 63];
word2 = word2 - ctx->S[word1 & 63];
word1 = word1 - ctx->S[word0 & 63];
word0 = word0 - ctx->S[word3 & 63];
}
}
outbuf[0] = word0 & 255;
outbuf[1] = word0 >> 8;
outbuf[2] = word1 & 255;
outbuf[3] = word1 >> 8;
outbuf[4] = word2 & 255;
outbuf[5] = word2 >> 8;
outbuf[6] = word3 & 255;
outbuf[7] = word3 >> 8;
}
static unsigned int
decrypt_block (void *context, unsigned char *outbuf, const unsigned char *inbuf)
{
do_decrypt (context, outbuf, inbuf);
return /*burn_stack*/ (4 * sizeof(void *) + sizeof(void *) + sizeof(u32) * 4);
}
static gpg_err_code_t
setkey_core (void *context, const unsigned char *key, unsigned int keylen, int with_phase2)
{
static int initialized;
static const char *selftest_failed;
RFC2268_context *ctx = context;
unsigned int i;
unsigned char *S, x;
int len;
int bits = keylen * 8;
if (!initialized)
{
initialized = 1;
selftest_failed = selftest ();
if (selftest_failed)
log_error ("RFC2268 selftest failed (%s).\n", selftest_failed);
}
if (selftest_failed)
return GPG_ERR_SELFTEST_FAILED;
if (keylen < 40 / 8) /* We want at least 40 bits. */
return GPG_ERR_INV_KEYLEN;
if (keylen > 128)
return GPG_ERR_INV_KEYLEN;
S = (unsigned char *) ctx->S;
for (i = 0; i < keylen; i++)
S[i] = key[i];
for (i = keylen; i < 128; i++)
S[i] = rfc2268_sbox[(S[i - keylen] + S[i - 1]) & 255];
S[0] = rfc2268_sbox[S[0]];
/* Phase 2 - reduce effective key size to "bits". This was not
* discussed in Gutmann's paper. I've copied that from the public
* domain code posted in sci.crypt. */
if (with_phase2)
{
len = (bits + 7) >> 3;
i = 128 - len;
x = rfc2268_sbox[S[i] & (255 >> (7 & -bits))];
S[i] = x;
while (i--)
{
x = rfc2268_sbox[x ^ S[i + len]];
S[i] = x;
}
}
/* Make the expanded key, endian independent. */
for (i = 0; i < 64; i++)
ctx->S[i] = ( (u16) S[i * 2] | (((u16) S[i * 2 + 1]) << 8));
return 0;
}
static gpg_err_code_t
do_setkey (void *context, const unsigned char *key, unsigned int keylen,
cipher_bulk_ops_t *bulk_ops)
{
(void)bulk_ops;
return setkey_core (context, key, keylen, 1);
}
static const char *
selftest (void)
{
RFC2268_context ctx;
unsigned char scratch[16];
/* Test vectors from Peter Gutmann's paper. */
static unsigned char key_1[] =
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static unsigned char plaintext_1[] =
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
static const unsigned char ciphertext_1[] =
{ 0x1C, 0x19, 0x8A, 0x83, 0x8D, 0xF0, 0x28, 0xB7 };
static unsigned char key_2[] =
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
};
static unsigned char plaintext_2[] =
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
static unsigned char ciphertext_2[] =
{ 0x50, 0xDC, 0x01, 0x62, 0xBD, 0x75, 0x7F, 0x31 };
/* This one was checked against libmcrypt's RFC2268. */
static unsigned char key_3[] =
{ 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static unsigned char plaintext_3[] =
{ 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
static unsigned char ciphertext_3[] =
{ 0x8f, 0xd1, 0x03, 0x89, 0x33, 0x6b, 0xf9, 0x5e };
/* First test. */
setkey_core (&ctx, key_1, sizeof(key_1), 0);
do_encrypt (&ctx, scratch, plaintext_1);
if (memcmp (scratch, ciphertext_1, sizeof(ciphertext_1)))
return "RFC2268 encryption test 1 failed.";
setkey_core (&ctx, key_1, sizeof(key_1), 0);
do_decrypt (&ctx, scratch, scratch);
if (memcmp (scratch, plaintext_1, sizeof(plaintext_1)))
return "RFC2268 decryption test 1 failed.";
/* Second test. */
setkey_core (&ctx, key_2, sizeof(key_2), 0);
do_encrypt (&ctx, scratch, plaintext_2);
if (memcmp (scratch, ciphertext_2, sizeof(ciphertext_2)))
return "RFC2268 encryption test 2 failed.";
setkey_core (&ctx, key_2, sizeof(key_2), 0);
do_decrypt (&ctx, scratch, scratch);
if (memcmp (scratch, plaintext_2, sizeof(plaintext_2)))
return "RFC2268 decryption test 2 failed.";
/* Third test. */
setkey_core(&ctx, key_3, sizeof(key_3), 0);
do_encrypt(&ctx, scratch, plaintext_3);
if (memcmp(scratch, ciphertext_3, sizeof(ciphertext_3)))
return "RFC2268 encryption test 3 failed.";
setkey_core (&ctx, key_3, sizeof(key_3), 0);
do_decrypt (&ctx, scratch, scratch);
if (memcmp(scratch, plaintext_3, sizeof(plaintext_3)))
return "RFC2268 decryption test 3 failed.";
return NULL;
}
static const gcry_cipher_oid_spec_t oids_rfc2268_40[] =
{
/*{ "1.2.840.113549.3.2", GCRY_CIPHER_MODE_CBC },*/
/* pbeWithSHAAnd40BitRC2_CBC */
{ "1.2.840.113549.1.12.1.6", GCRY_CIPHER_MODE_CBC },
{ NULL }
};
static const gcry_cipher_oid_spec_t oids_rfc2268_128[] =
{
/* pbeWithSHAAnd128BitRC2_CBC */
{ "1.2.840.113549.1.12.1.5", GCRY_CIPHER_MODE_CBC },
{ NULL }
};
gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_40 =
{
GCRY_CIPHER_RFC2268_40, {0, 0},
"RFC2268_40", NULL, oids_rfc2268_40,
RFC2268_BLOCKSIZE, 40, sizeof(RFC2268_context),
do_setkey, encrypt_block, decrypt_block
};
gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_128 =
{
GCRY_CIPHER_RFC2268_128, {0, 0},
"RFC2268_128", NULL, oids_rfc2268_128,
RFC2268_BLOCKSIZE, 128, sizeof(RFC2268_context),
do_setkey, encrypt_block, decrypt_block
};

File Metadata

Mime Type
text/x-c
Expires
Sat, Feb 1, 9:24 AM (1 d, 13 h)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
19/1b/ea1f0e888c3fce405a01f1a6e1ca

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