Add utility to pad a given hash for PKCS1.5 signatures

utility/signature_digest_utility.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Utility that outputs the cryptographic digest of a contents of a
  * file in a format that can be directly used to generate PKCS#1 v1.5
  * signatures via the "openssl" command line utility.
  */
 
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "file_keys.h"
 #include "padding.h"
 #include "signature_digest.h"
 #include "utility.h"
 
 int main(int argc, char* argv[]) {
   int algorithm = -1;
   int error_code = 0;
   uint8_t* buf = NULL;
   uint8_t* signature_digest = NULL;
   uint64_t len;
   uint32_t signature_digest_len;
 
   if (argc != 3) {
-    fprintf(stderr, "Usage: %s <algoid> <file>", argv[0]);
+    fprintf(stderr, "Usage: %s <alg_id> <file>", argv[0]);
     return -1;
   }
   algorithm = atoi(argv[1]);
   if (algorithm < 0 || algorithm >= kNumAlgorithms) {
     fprintf(stderr, "Invalid Algorithm!\n");
     return -1;
   }
 
   buf = BufferFromFile(argv[2], &len);
   if (!buf) {
-    fprintf(stderr, "Could read file: %s\n", argv[2]);
+    fprintf(stderr, "Could not read file: %s\n", argv[2]);
     return -1;
   }
 
   signature_digest = SignatureDigest(buf, len, algorithm);
   signature_digest_len = (hash_size_map[algorithm] +
                           digestinfo_size_map[algorithm]);
   if (!signature_digest)
     error_code = -1;
   if(signature_digest &&
      1 != fwrite(signature_digest, signature_digest_len, 1, stdout))
     error_code = -1;
   Free(signature_digest);
   Free(buf);
   return error_code;
 }