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Diffstat (limited to 'demos/digest/BIO_f_md.c')
-rwxr-xr-x | demos/digest/BIO_f_md.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/demos/digest/BIO_f_md.c b/demos/digest/BIO_f_md.c new file mode 100755 index 0000000000..ce1dfcc34a --- /dev/null +++ b/demos/digest/BIO_f_md.c @@ -0,0 +1,122 @@ +/*- + * 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 BIO_f_md: + * echo "1ca984dcc913344370cf" | xxd -r -p | ./BIO_f_md + * and then verify the output matches MD above. + */ + +#include <string.h> +#include <stdio.h> +#include <openssl/err.h> +#include <openssl/bio.h> +#include <openssl/evp.h> + +/*- + * This demonstration will show how to digest data using + * a BIO configured with a message digest + * A message digest name may be passed as an argument. + * The default digest is SHA3-512 + */ + +int main(int argc, char * argv[]) +{ + int result = 1; + OSSL_LIB_CTX *library_context = NULL; + BIO *input = NULL; + BIO *bio_digest = NULL; + EVP_MD *md = NULL; + unsigned char buffer[512]; + size_t readct, writect; + size_t digest_size; + char *digest_value=NULL; + int j; + + input = BIO_new_fd( fileno(stdin), 1 ); + if (input == NULL) { + fprintf(stderr, "BIO_new_fd() for stdin returned NULL\n"); + goto cleanup; + } + 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 + */ + md = EVP_MD_fetch( library_context, "SHA3-512", NULL ); + if (md == NULL) { + fprintf(stderr, "EVP_MD_fetch did not find SHA3-512.\n"); + goto cleanup; + } + digest_size = EVP_MD_size(md); + digest_value = OPENSSL_malloc(digest_size); + if (digest_value == NULL) { + fprintf(stderr, "Can't allocate %lu bytes for the digest value.\n", (unsigned long)digest_size); + goto cleanup; + } + /* Make a bio that uses the digest */ + bio_digest = BIO_new(BIO_f_md()); + if (bio_digest == NULL) { + fprintf(stderr, "BIO_new(BIO_f_md()) returned NULL\n"); + goto cleanup; + } + /* set our bio_digest BIO to digest data */ + if (BIO_set_md(bio_digest,md) != 1) { + fprintf(stderr, "BIO_set_md failed.\n"); + goto cleanup; + } + /*- + * We will use BIO chaining so that as we read, the digest gets updated + * See the man page for BIO_push + */ + BIO *reading = BIO_push( bio_digest, input ); + + while( BIO_read(reading, buffer, sizeof(buffer)) > 0 ) + ; + + /*- + * BIO_gets must be used to calculate the final + * digest value and then copy it to digest_value. + */ + if (BIO_gets(bio_digest, digest_value, digest_size) != digest_size) { + fprintf(stderr, "BIO_gets(bio_digest) failed\n"); + goto cleanup; + } + for (j=0; j<digest_size; j++) { + fprintf(stdout, "%02x", (unsigned char)digest_value[j]); + } + fprintf(stdout, "\n"); + result = 0; + +cleanup: + if (result != 0) + ERR_print_errors_fp(stderr); + + OPENSSL_free(digest_value); + BIO_free(input); + BIO_free(bio_digest); + EVP_MD_free(md); + OSSL_LIB_CTX_free(library_context); + + return result; +} |