/*
* cipher.c
*
* cipher meta-functions
*
* David A. McGrew
* Cisco Systems, Inc.
*
*/
/*
*
* Copyright (c) 2001-2006, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "cipher.h"
#include "rand_source.h" /* used in invertibiltiy tests */
#include "alloc.h" /* for crypto_alloc(), crypto_free() */
debug_module_t mod_cipher = {
0, /* debugging is off by default */
"cipher" /* printable module name */
};
err_status_t
cipher_output(cipher_t *c, uint8_t *buffer, int num_octets_to_output) {
/* zeroize the buffer */
octet_string_set_to_zero(buffer, num_octets_to_output);
/* exor keystream into buffer */
return cipher_encrypt(c, buffer, (unsigned int *) &num_octets_to_output);
}
/* some bookkeeping functions */
int
cipher_get_key_length(const cipher_t *c) {
return c->key_len;
}
/*
* cipher_type_self_test(ct) tests a cipher of type ct against test cases
* provided in an array of values of key, salt, xtd_seq_num_t,
* plaintext, and ciphertext that is known to be good
*/
#define SELF_TEST_BUF_OCTETS 128
#define NUM_RAND_TESTS 128
#define MAX_KEY_LEN 64
err_status_t
cipher_type_self_test(const cipher_type_t *ct) {
const cipher_test_case_t *test_case = ct->test_data;
cipher_t *c;
err_status_t status;
uint8_t buffer[SELF_TEST_BUF_OCTETS];
uint8_t buffer2[SELF_TEST_BUF_OCTETS];
unsigned int len;
int i, j, case_num = 0;
debug_print(mod_cipher, "running self-test for cipher %s",
ct->description);
/*
* check to make sure that we have at least one test case, and
* return an error if we don't - we need to be paranoid here
*/
if (test_case == NULL)
return err_status_cant_check;
/*
* loop over all test cases, perform known-answer tests of both the
* encryption and decryption functions
*/
while (test_case != NULL) {
/* allocate cipher */
status = cipher_type_alloc(ct, &c, test_case->key_length_octets);
if (status)
return status;
/*
* test the encrypt function
*/
debug_print(mod_cipher, "testing encryption", NULL);
/* initialize cipher */
status = cipher_init(c, test_case->key, direction_encrypt);
if (status) {
cipher_dealloc(c);
return status;
}
/* copy plaintext into test buffer */
if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
cipher_dealloc(c);
return err_status_bad_param;
}
for (i=0; i < test_case->plaintext_length_octets; i++)
buffer[i] = test_case->plaintext[i];
debug_print(mod_cipher, "plaintext: %s",
octet_string_hex_string(buffer,
test_case->plaintext_length_octets));
/* set the initialization vector */
status = cipher_set_iv(c, test_case->idx);
if (status) {
cipher_dealloc(c);
return status;
}
/* encrypt */
len = test_case->plaintext_length_octets;
status = cipher_encrypt(c, buffer, &len);
if (status) {
cipher_dealloc(c);
return status;
}
debug_print(mod_cipher, "ciphertext: %s",
octet_string_hex_string(buffer,
test_case->ciphertext_length_octets));
/* compare the resulting ciphertext with that in the test case */
if (len != test_case->ciphertext_length_octets)
return err_status_algo_fail;
status = err_status_ok;
for (i=0; i < test_case->ciphertext_length_octets; i++)
if (buffer[i] != test_case->ciphertext[i]) {
status = err_status_algo_fail;
debug_print(mod_cipher, "test case %d failed", case_num);
debug_print(mod_cipher, "(failure at byte %d)", i);
break;
}
if (status) {
debug_print(mod_cipher, "c computed: %s",
octet_string_hex_string(buffer,
2*test_case->plaintext_length_octets));
debug_print(mod_cipher, "c expected: %s",
octet_string_hex_string(test_case->ciphertext,
2*test_case->plaintext_length_octets));
cipher_dealloc(c);
return err_status_algo_fail;
}
/*
* test the decrypt function
*/
debug_print(mod_cipher, "testing decryption", NULL);
/* re-initialize cipher for decryption */
status = cipher_init(c, test_case->key, direction_decrypt);
if (status) {
cipher_dealloc(c);
return status;
}
/* copy ciphertext into test buffer */
if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
cipher_dealloc(c);
return err_status_bad_param;
}
for (i=0; i < test_case->ciphertext_length_octets; i++)
buffer[i] = test_case->ciphertext[i];
debug_print(mod_cipher, "ciphertext: %s",
octet_string_hex_string(buffer,
test_case->plaintext_length_octets));
/* set the initialization vector */
status = cipher_set_iv(c, test_case->idx);
if (status) {
cipher_dealloc(c);
return status;
}
/* decrypt */
len = test_case->ciphertext_length_octets;
status = cipher_decrypt(c, buffer, &len);
if (status) {
cipher_dealloc(c);
return status;
}
debug_print(mod_cipher, "plaintext: %s",
octet_string_hex_string(buffer,
test_case->plaintext_length_octets));
/* compare the resulting plaintext with that in the test case */
if (len != test_case->plaintext_length_octets)
return err_status_algo_fail;
status = err_status_ok;
for (i=0; i < test_case->plaintext_length_octets; i++)
if (buffer[i] != test_case->plaintext[i]) {
status = err_status_algo_fail;
debug_print(mod_cipher, "test case %d failed", case_num);
debug_print(mod_cipher, "(failure at byte %d)", i);
}
if (status) {
debug_print(mod_cipher, "p computed: %s",
octet_string_hex_string(buffer,
2*test_case->plaintext_length_octets));
debug_print(mod_cipher, "p expected: %s",
octet_string_hex_string(test_case->plaintext,
2*test_case->plaintext_length_octets));
cipher_dealloc(c);
return err_status_algo_fail;
}
/* deallocate the cipher */
status = cipher_dealloc(c);
if (status)
return status;
/*
* the cipher passed the test case, so move on to the next test
* case in the list; if NULL, we'l proceed to the next test
*/
test_case = test_case->next_test_case;
++case_num;
}
/* now run some random invertibility tests */
/* allocate cipher, using paramaters from the first test case */
test_case = ct->test_data;
status = cipher_type_alloc(ct, &c, test_case->key_length_octets);
if (status)
return status;
rand_source_init();
for (j=0; j < NUM_RAND_TESTS; j++) {
unsigned length;
int plaintext_len;
uint8_t key[MAX_KEY_LEN];
uint8_t iv[MAX_KEY_LEN];
/* choose a length at random (leaving room for IV and padding) */
length = rand() % (SELF_TEST_BUF_OCTETS - 64);
debug_print(mod_cipher, "random plaintext length %d\n", length);
status = rand_source_get_octet_string(buffer, length);
if (status) return status;
debug_print(mod_cipher, "plaintext: %s",
octet_string_hex_string(buffer, length));
/* copy plaintext into second buffer */
for (i=0; (unsigned int)i < length; i++)
buffer2[i] = buffer[i];
/* choose a key at random */
if (test_case->key_length_octets > MAX_KEY_LEN)
return err_status_cant_check;
status = rand_source_get_octet_string(key, test_case->key_length_octets);
if (status) return status;
/* chose a random initialization vector */
status = rand_source_get_octet_string(iv, MAX_KEY_LEN);
if (status) return status;
/* initialize cipher */
status = cipher_init(c, key, direction_encrypt);
if (status) {
cipher_dealloc(c);
return status;
}
/* set initialization vector */
status = cipher_set_iv(c, test_case->idx);
if (status) {
cipher_dealloc(c);
return status;
}
/* encrypt buffer with cipher */
plaintext_len = length;
status = cipher_encrypt(c, buffer, &length);
if (status) {
cipher_dealloc(c);
return status;
}
debug_print(mod_cipher, "ciphertext: %s",
octet_string_hex_string(buffer, length));
/*
* re-initialize cipher for decryption, re-set the iv, then
* decrypt the ciphertext
*/
status = cipher_init(c, key, direction_decrypt);
if (status) {
cipher_dealloc(c);
return status;
}
status = cipher_set_iv(c, test_case->idx);
if (status) {
cipher_dealloc(c);
return status;
}
status = cipher_decrypt(c, buffer, &length);
if (status) {
cipher_dealloc(c);
return status;
}
debug_print(mod_cipher, "plaintext[2]: %s",
octet_string_hex_string(buffer, length));
/* compare the resulting plaintext with the original one */
if (length != plaintext_len)
return err_status_algo_fail;
status = err_status_ok;
for (i=0; i < plaintext_len; i++)
if (buffer[i] != buffer2[i]) {
status = err_status_algo_fail;
debug_print(mod_cipher, "random test case %d failed", case_num);
debug_print(mod_cipher, "(failure at byte %d)", i);
}
if (status) {
cipher_dealloc(c);
return err_status_algo_fail;
}
}
return err_status_ok;
}
/*
* cipher_bits_per_second(c, l, t) computes (an estimate of) the
* number of bits that a cipher implementation can encrypt in a second
*
* c is a cipher (which MUST be allocated and initialized already), l
* is the length in octets of the test data to be encrypted, and t is
* the number of trials
*
* if an error is encountered, the value 0 is returned
*/
uint64_t
cipher_bits_per_second(cipher_t *c, int octets_in_buffer, int num_trials) {
int i;
v128_t nonce;
clock_t timer;
unsigned char *enc_buf;
unsigned int len = octets_in_buffer;
enc_buf = (unsigned char*) crypto_alloc(octets_in_buffer);
if (enc_buf == NULL)
return 0; /* indicate bad parameters by returning null */
/* time repeated trials */
v128_set_to_zero(&nonce);
timer = clock();
for(i=0; i < num_trials; i++, nonce.v32[3] = i) {
cipher_set_iv(c, &nonce);
cipher_encrypt(c, enc_buf, &len);
}
timer = clock() - timer;
crypto_free(enc_buf);
if (timer == 0) {
/* Too fast! */
return 0;
}
return (uint64_t)CLOCKS_PER_SEC * num_trials * 8 * octets_in_buffer / timer;
}