example_evp_cipher.c

This is an example how to use EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex().

/*
* Copyright (c) 2008 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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 <config.h>
#include <roken.h>
#include <krb5-types.h> /* should really be stdint.h */
#include <hcrypto/evp.h>
#include <hcrypto/evp-pkcs11.h>
#ifdef __APPLE__
#include <hcrypto/evp-cc.h>
#endif
#ifdef _WIN32
#include <hcrypto/evp-w32.h>
#endif
#include <err.h>
#include <assert.h>
/* key and initial vector */
static char key[16] =
"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"
"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4";
static char ivec[16] =
"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"
"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4";
static void
usage(int exit_code) __attribute__((noreturn));
static void
usage(int exit_code)
{
printf("usage: %s in out [pkcs11 | cc | w32]\n", getprogname());
exit(exit_code);
}
int
main(int argc, char **argv)
{
int encryptp = 1;
const char *ifn = NULL, *ofn = NULL;
FILE *in, *out;
void *ibuf, *obuf;
int ilen, olen;
size_t block_size = 0;
const EVP_CIPHER *c = EVP_aes_128_cbc();
EVP_CIPHER_CTX ctx;
int ret;
setprogname(argv[0]);
if (argc == 2) {
if (strcmp(argv[1], "--version") == 0) {
printf("version");
exit(0);
}
if (strcmp(argv[1], "--help") == 0)
usage(0);
usage(1);
} else if (argc == 4 || argc == 5) {
block_size = atoi(argv[1]);
if (block_size == 0)
errx(1, "invalid blocksize %s", argv[1]);
ifn = argv[2];
ofn = argv[3];
if (argc == 5) {
if (strcmp(argv[4], "pkcs11") == 0)
c = hc_EVP_pkcs11_aes_128_cbc();
#ifdef __APPLE__
else if (strcmp(argv[4], "cc") == 0)
c = hc_EVP_cc_aes_128_cbc();
#endif
#ifdef _WIN32
else if (strcmp(argv[4], "w32") == 0)
c = hc_EVP_w32crypto_aes_128_cbc();
#endif
else
usage(1);
}
} else
usage(1);
in = fopen(ifn, "r");
if (in == NULL)
errx(1, "failed to open input file");
out = fopen(ofn, "w+");
if (out == NULL)
errx(1, "failed to open output file");
/* Check that key and ivec are long enough */
assert(EVP_CIPHER_key_length(c) <= sizeof(key));
assert(EVP_CIPHER_iv_length(c) <= sizeof(ivec));
/*
* Allocate buffer, the output buffer is at least
* EVP_CIPHER_block_size() longer
*/
ibuf = malloc(block_size);
obuf = malloc(block_size + EVP_CIPHER_block_size(c));
/*
* Init the memory used for EVP_CIPHER_CTX and set the key and
* ivec.
*/
EVP_CIPHER_CTX_init(&ctx);
EVP_CipherInit_ex(&ctx, c, NULL, key, ivec, encryptp);
/* read in buffer */
while ((ilen = fread(ibuf, 1, block_size, in)) > 0) {
/* encrypto/decrypt */
ret = EVP_CipherUpdate(&ctx, obuf, &olen, ibuf, ilen);
if (ret != 1) {
EVP_CIPHER_CTX_cleanup(&ctx);
errx(1, "EVP_CipherUpdate failed");
}
/* write out to output file */
fwrite(obuf, 1, olen, out);
}
/* done reading */
fclose(in);
/* clear up any last bytes left in the output buffer */
ret = EVP_CipherFinal_ex(&ctx, obuf, &olen);
EVP_CIPHER_CTX_cleanup(&ctx);
if (ret != 1)
errx(1, "EVP_CipherFinal_ex failed");
/* write the last bytes out and close */
fwrite(obuf, 1, olen, out);
fclose(out);
return 0;
}
EVP_CIPHER_CTX_init
void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *c)
Definition: evp.c:570
EVP_aes_128_cbc
const EVP_CIPHER * EVP_aes_128_cbc(void)
Definition: evp.c:1153
EVP_CIPHER_block_size
size_t EVP_CIPHER_block_size(const EVP_CIPHER *c)
Definition: evp.c:523
EVP_CIPHER_key_length
size_t EVP_CIPHER_key_length(const EVP_CIPHER *c)
Definition: evp.c:539
EVP_CipherFinal_ex
int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, void *out, int *outlen)
Definition: evp.c:939
EVP_CIPHER_iv_length
size_t EVP_CIPHER_iv_length(const EVP_CIPHER *c)
Definition: evp.c:555
EVP_CipherUpdate
int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, void *out, int *outlen, void *in, size_t inlen)
Definition: evp.c:853
EVP_CipherInit_ex
int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *c, ENGINE *engine, const void *key, const void *iv, int encp)
Definition: evp.c:775
EVP_CIPHER_CTX_cleanup
int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
Definition: evp.c:586