implemented PGP fingerprinting

2009-08-26 11:23:51 +02:00
parent e773fe4cab
commit d1b3e8607e
4 changed files with 107 additions and 0 deletions
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2009 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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 the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "pgp_encoder.h"
+
+#include <debug.h>
+
+/**
+ * Build a PGPv3 fingerprint
+ */
+static bool build_v3_fingerprint(chunk_t *encoding, va_list args)
+{
+	hasher_t *hasher;
+	chunk_t n, e;
+	
+	if (key_encoding_args(args, KEY_PART_RSA_MODULUS, &n,
+						  KEY_PART_RSA_PUB_EXP, &e, KEY_PART_END))
+	{
+		hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5);
+		if (!hasher)
+		{
+			DBG1("MD5 hash algorithm not supported, PGP fingerprinting failed");
+			return FALSE;
+		}
+		/* remove leading zero bytes before hashing modulus and exponent */
+		while (n.len > 0 && n.ptr[0] == 0x00)
+		{
+			n = chunk_skip(n, 1);
+		}
+		while (e.len > 0 && e.ptr[0] == 0x00)
+		{
+			e = chunk_skip(e, 1);
+		}
+		hasher->allocate_hash(hasher, n, NULL);
+		hasher->allocate_hash(hasher, e, encoding);
+		hasher->destroy(hasher);
+		return TRUE;
+	}
+	return FALSE;
+}
+
+/**
+ * See header.
+ */
+bool pgp_encoder_encode(key_encoding_type_t type, chunk_t *encoding,
+						  va_list args)
+{
+	switch (type)
+	{
+		case KEY_ID_PGPV3:
+			return build_v3_fingerprint(encoding, args);
+		default:
+			return FALSE;
+	}
+}
+