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/* ====================================================================
* Copyright (c) 2008 The OpenSSL Project. All rights reserved.
*
* Rights for redistribution and usage in source and binary
* forms are granted according to the OpenSSL license.
*/
#include "modes.h"
#include <string.h>
#ifndef MODES_DEBUG
# ifndef NDEBUG
# define NDEBUG
# endif
#endif
#include <assert.h>
/*
* Trouble with Ciphertext Stealing, CTS, mode is that there is no
* common official specification, but couple of cipher/application
* specific ones: RFC2040 and RFC3962. Then there is 'Proposal to
* Extend CBC Mode By "Ciphertext Stealing"' at NIST site, which
* deviates from mentioned RFCs. Most notably it allows input to be
* of block length and it doesn't flip the order of the last two
* blocks. CTS is being discussed even in ECB context, but it's not
* adopted for any known application. This implementation complies
* with mentioned RFCs and [as such] extends CBC mode.
*/
size_t CRYPTO_cts128_encrypt_block(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], block128_f block)
{ size_t residue, n;
assert (in && out && key && ivec);
if (len <= 16) return 0;
if ((residue=len%16) == 0) residue = 16;
len -= residue;
CRYPTO_cbc128_encrypt(in,out,len,key,ivec,block);
in += len;
out += len;
for (n=0; n<residue; ++n)
ivec[n] ^= in[n];
(*block)(ivec,ivec,key);
memcpy(out,out-16,residue);
memcpy(out-16,ivec,16);
return len+residue;
}
size_t CRYPTO_cts128_encrypt(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], cbc128_f cbc)
{ size_t residue;
union { size_t align; unsigned char c[16]; } tmp;
assert (in && out && key && ivec);
if (len <= 16) return 0;
if ((residue=len%16) == 0) residue = 16;
len -= residue;
(*cbc)(in,out,len,key,ivec,1);
in += len;
out += len;
#if defined(CBC_HANDLES_TRUNCATED_IO)
memcpy(tmp.c,out-16,16);
(*cbc)(in,out-16,residue,key,ivec,1);
memcpy(out,tmp.c,residue);
#else
memset(tmp.c,0,sizeof(tmp));
memcpy(tmp.c,in,residue);
memcpy(out,out-16,residue);
(*cbc)(tmp.c,out-16,16,key,ivec,1);
#endif
return len+residue;
}
size_t CRYPTO_cts128_decrypt_block(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], block128_f block)
{ size_t residue, n;
union { size_t align; unsigned char c[32]; } tmp;
assert (in && out && key && ivec);
if (len<=16) return 0;
if ((residue=len%16) == 0) residue = 16;
len -= 16+residue;
if (len) {
CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block);
in += len;
out += len;
}
(*block)(in,tmp.c+16,key);
memcpy(tmp.c,tmp.c+16,16);
memcpy(tmp.c,in+16,residue);
(*block)(tmp.c,tmp.c,key);
for(n=0; n<16; ++n) {
unsigned char c = in[n];
out[n] = tmp.c[n] ^ ivec[n];
ivec[n] = c;
}
for(residue+=16; n<residue; ++n)
out[n] = tmp.c[n] ^ in[n];
return len+residue-16;
}
size_t CRYPTO_cts128_decrypt(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], cbc128_f cbc)
{ size_t residue;
union { size_t align; unsigned char c[32]; } tmp;
assert (in && out && key && ivec);
if (len<=16) return 0;
if ((residue=len%16) == 0) residue = 16;
len -= 16+residue;
if (len) {
(*cbc)(in,out,len,key,ivec,0);
in += len;
out += len;
}
memset(tmp.c,0,sizeof(tmp));
/* this places in[16] at &tmp.c[16] and decrypted block at &tmp.c[0] */
(*cbc)(in,tmp.c,16,key,tmp.c+16,0);
memcpy(tmp.c,in+16,residue);
#if defined(CBC_HANDLES_TRUNCATED_IO)
(*cbc)(tmp.c,out,16+residue,key,ivec,0);
#else
(*cbc)(tmp.c,tmp.c,32,key,ivec,0);
memcpy(out,tmp.c,16+residue);
#endif
return len+residue;
}
#if defined(SELFTEST)
#include <stdio.h>
#include <openssl/aes.h>
/* test vectors from RFC 3962 */
static const unsigned char test_key[16] = "chicken teriyaki";
static const unsigned char test_input[64] =
"I would like the" " General Gau's C"
"hicken, please, " "and wonton soup.";
static const unsigned char test_iv[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
static const unsigned char vector_17[17] = {
0xc6,0x35,0x35,0x68,0xf2,0xbf,0x8c,0xb4,
0xd8,0xa5,0x80,0x36,0x2d,0xa7,0xff,0x7f,
0x97};
static const unsigned char vector_31[31] = {
0xfc,0x00,0x78,0x3e,0x0e,0xfd,0xb2,0xc1,
0xd4,0x45,0xd4,0xc8,0xef,0xf7,0xed,0x22,
0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0,
0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5};
static const unsigned char vector_32[32] = {
0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5,
0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8,
0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0,
0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84};
static const unsigned char vector_47[47] = {
0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0,
0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84,
0xb3,0xff,0xfd,0x94,0x0c,0x16,0xa1,0x8c,
0x1b,0x55,0x49,0xd2,0xf8,0x38,0x02,0x9e,
0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5,
0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5};
static const unsigned char vector_48[48] = {
0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0,
0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84,
0x9d,0xad,0x8b,0xbb,0x96,0xc4,0xcd,0xc0,
0x3b,0xc1,0x03,0xe1,0xa1,0x94,0xbb,0xd8,
0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5,
0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8};
static const unsigned char vector_64[64] = {
0x97,0x68,<
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