Code auditing weekend results and fixes committing.

[silc.git] / lib / silccrypt / silchash.c

diff --git a/lib/silccrypt/silchash.c b/lib/silccrypt/silchash.c
index 547cb60d0a42421f7c4d6c4270ebe96f77bc188b..8bb7339336e98188d45ec00925a4c02b0527d3f5 100644 (file)
--- a/lib/silccrypt/silchash.c
+++ b/lib/silccrypt/silchash.c
@@ -4,7 +4,7 @@
 
   Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
 
-  Copyright (C) 1997 - 2000 Pekka Riikonen
+  Copyright (C) 1997 - 2001 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -17,17 +17,7 @@
   GNU General Public License for more details.
 
 */
-/*
- * $Id$
- * $Log$
- * Revision 1.2  2000/07/05 06:08:43  priikone
- *     Global cosmetic change.
- *
- * Revision 1.1.1.1  2000/06/27 11:36:55  priikone
- *     Imported from internal CVS/Added Log headers.
- *
- *
- */
+/* $Id$ */
 
 #include "silcincludes.h"
 
@@ -279,3 +269,35 @@ void silc_hash_make(SilcHash hash, const unsigned char *data,
   hash->hash->update(hash->context, (unsigned char *)data, len);
   hash->hash->final(hash->context, return_hash);
 }
+
+/* Creates fingerprint of the data. If `hash' is NULL SHA1 is used as
+   default hash function. The returned fingerprint must be free's by the
+   caller. */
+
+char *silc_hash_fingerprint(SilcHash hash, const unsigned char *data,
+                           unsigned int data_len)
+{
+  char fingerprint[64], *cp;
+  unsigned char h[32];
+  int i;
+
+  if (!hash)
+    silc_hash_alloc("sha1", &hash);
+
+  silc_hash_make(hash, data, data_len, h);
+  
+  memset(fingerprint, 0, sizeof(fingerprint));
+  cp = fingerprint;
+  for (i = 0; i < hash->hash->hash_len; i++) {
+    snprintf(cp, sizeof(fingerprint), "%02X", h[i]);
+    cp += 2;
+    
+    if ((i + 1) % 2 == 0)
+      snprintf(cp++, sizeof(fingerprint), " ");
+
+    if ((i + 1) % 10 == 0)
+      snprintf(cp++, sizeof(fingerprint), " ");
+  }
+  
+  return strdup(fingerprint);
+}