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/*-
* Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*-
* Example of using EVP_MD_fetch and EVP_Digest* methods to calculate
* a digest of static buffers
* You can find SHA3 test vectors from NIST here:
* https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Algorithm-Validation-Program/documents/sha3/sha-3bytetestvectors.zip
* For example, contains these lines:
Len = 80
Msg = 1ca984dcc913344370cf
MD = 6915ea0eeffb99b9b246a0e34daf3947852684c3d618260119a22835659e4f23d4eb66a15d0affb8e93771578f5e8f25b7a5f2a55f511fb8b96325ba2cd14816
* use xxd convert the hex message string to binary input for EVP_MD_stdin:
* echo "1ca984dcc913344370cf" | xxd -r -p | ./EVP_MD_stdin
* and then verify the output matches MD above.
*/
#include <string.h>
#include <stdio.h>
#include <openssl/err.h>
#include <openssl/evp.h>
/*-
* This demonstration will show how to digest data using
* a BIO created to read from stdin
*/
int demonstrate_digest(BIO *input)
{
OSSL_LIB_CTX *library_context = NULL;
int ret = 0;
const char * option_properties = NULL;
EVP_MD *message_digest = NULL;
EVP_MD_CTX *digest_context = NULL;
unsigned int digest_length;
unsigned char *digest_value = NULL;
unsigned char buffer[512];
int ii;
library_context = OSSL_LIB_CTX_new();
if (library_context == NULL) {
fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
goto cleanup;
}
/*
* Fetch a message digest by name
* The algorithm name is case insensitive.
* See providers(7) for details about algorithm fetching
*/
message_digest = EVP_MD_fetch(library_context,
"SHA3-512", option_properties);
if (message_digest == NULL) {
fprintf(stderr, "EVP_MD_fetch could not find SHA3-512.");
ERR_print_errors_fp(stderr);
OSSL_LIB_CTX_free(library_context);
return 0;
}
/* Determine the length of the fetched digest type */
digest_length = EVP_MD_get_size(message_digest);
if (digest_length <= 0) {
fprintf(stderr, "EVP_MD_get_size returned invalid size.\n");
goto cleanup;
}
digest_value = OPENSSL_malloc(digest_length);
if (digest_value == NULL) {
fprintf(stderr, "No memory.\n");
goto cleanup;
}
/*
* Make a message digest context to hold temporary state
* during digest creation
*/
digest_context = EVP_MD_CTX_new();
if (digest_context == NULL) {
fprintf(stderr, "EVP_MD_CTX_new failed.\n");
ERR_print_errors_fp(stderr);
goto cleanup;
}
/*
* Initialize the message digest context to use the fetched
* digest provider
*/
if (EVP_DigestInit(digest_context, message_digest) != 1) {
fprintf(stderr, "EVP_DigestInit failed.\n");
ERR_print_errors_fp(stderr);
goto cleanup;
}
while ((ii = BIO_read(input, buffer, sizeof(buffer))) > 0) {
if (EVP_DigestUpdate(digest_context, buffer, ii) != 1) {
fprintf(stderr, "EVP_DigestUpdate() failed.\n");
goto cleanup;
}
}
if (EVP_DigestFinal(digest_context, digest_value, &digest_length) != 1) {
fprintf(stderr, "EVP_DigestFinal() failed.\n");
goto cleanup;
}
ret = 1;
for (ii=0; ii<digest_length; ii++) {
fprintf(stdout, "%02x", digest_value[ii]);
}
fprintf(stdout, "\n");
cleanup:
if (ret != 1)
ERR_print_errors_fp(stderr);
/* OpenSSL free functions will ignore NULL arguments */
EVP_MD_CTX_free(digest_context);
OPENSSL_free(digest_value);
EVP_MD_free(message_digest);
OSSL_LIB_CTX_free(library_context);
return ret;
}
int main(void)
{
int ret = EXIT_FAILURE;
BIO *input = BIO_new_fd(fileno(stdin), 1);
if (input != NULL) {
ret = (demonstrate_digest(input) ? EXIT_SUCCESS : EXIT_FAILURE);
BIO_free(input);
}
if (ret != EXIT_SUCCESS)
ERR_print_errors_fp(stderr);
return ret;
}
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