algorithm abstraction

src/algorithm.h

@@ -0,0 +1,61 @@
+
+/*
+ * This file is part of Codecrypt.
+ *
+ * Codecrypt is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Codecrypt 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 Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Codecrypt. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ccr_algorithm_h_
+#define _ccr_algorithm_h_
+
+#include "bvector.h"
+#include "prng.h"
+#include "sencode.h"
+
+#include <map>
+#include <string>
+class algorithm;
+typedef std::map<std::string, algorithm*> algorithm_suite;
+
+//virtual interface definition for all cryptographic algorithm instances
+class algorithm
+{
+public:
+	virtual bool provides_signatures() = 0;
+	virtual bool provides_encryption() = 0;
+	virtual std::string get_alg_id() = 0;
+
+	void register_into_suite (algorithm_suite&s) {
+		s[this->get_alg_id()] = this;
+	}
+
+	/*
+	 * note that these functions should be ready for different
+	 * plaintext/ciphertext/message lengths, usually padding them somehow.
+	 */
+	virtual int encrypt (const bvector&plain, bvector&cipher,
+	                     sencode* pubkey, prng&rng) = 0;
+
+	virtual int decrypt (const bvector&cipher, bvector&plain,
+	                     sencode* privkey) = 0;
+
+	virtual int sign (const bvector&msg, bvector&sig,
+	                  sencode* privkey, prng&rng) = 0;
+
+	virtual int verify (const bvector&sig, const bvector&msg,
+	                    sencode* pubkey) = 0;
+};
+
+#endif
+

src/message.cpp

@@ -18,11 +18,10 @@
 
 #include "message.h"
 
-#include "mce_qd.h"
-
 int encrypted_msg::encrypt (const bvector&msg,
-                            const std::string& Alg_id, const std::string& Key_id,
-                            keyring&kr, prng&rng)
+                            const std::string& Alg_id,
+                            const std::string& Key_id,
+                            algorithm_suite&algs, keyring&kr, prng&rng)
 {
 	key_id = Key_id;
 	alg_id = Alg_id;
@@ -30,36 +29,21 @@ int encrypted_msg::encrypt (const bvector&msg,
 	sencode*pubkey = kr.get_pubkey (key_id);
 	if (!pubkey) return 1; //PK not found
 
-	if (alg_id == "MCEQD-128") {
-	} else if (alg_id == "MCEQD-256") {
-		mce_qd::pubkey pk;
-		if (!pk.unserialize (pubkey) ) return 3; //Key unreadable
-
-		//TODO fujisaki-okamoto
-	} else return 2; //unknown algorithm
-
 	return 0;
 }
 
-int encrypted_msg::decrypt (bvector&msg, keyring&kr)
+int encrypted_msg::decrypt (bvector& msg, algorithm_suite&algs, keyring& kr)
 {
 	sencode*privkey = kr.get_privkey (key_id);
 	if (!privkey) return 1; //no key found
 
-	if (alg_id == "MCEQD-128") {
-	} else if (alg_id == "MCEQD-256") {
-		mce_qd::privkey sk;
-		if (!sk.unserialize (privkey) ) return 3; //key unreadable
-
-		//TODO fujisaki-okamoto
-	} else return 2; //unknown algorithm
-
 	return 0;
 }
 
 int signed_msg::sign (const bvector&msg,
-                      const std::string& Alg_id, const std::string&Key_id,
-                      keyring&kr, prng&rng)
+                      const std::string& Alg_id,
+                      const std::string& Key_id,
+                      algorithm_suite&algs, keyring&kr, prng&rng)
 {
 	key_id = Key_id;
 	alg_id = Alg_id;
@@ -68,25 +52,13 @@ int signed_msg::sign (const bvector&msg,
 	sencode*privkey = kr.get_privkey (key_id);
 	if (!privkey) return 1;
 
-	if (alg_id == "FMTSEQ-S256-128") {
-
-	} else if (alg_id == "FMTSEQ-S256-256") {
-
-		//TODO produce a reasonable signature
-	} else return 2; //unknown algorithm
-
+	return 0;
 }
 
-int signed_msg::verify (keyring&kr)
+int signed_msg::verify (algorithm_suite&algs, keyring&kr)
 {
 	sencode*pubkey = kr.get_pubkey (key_id);
 	if (!pubkey) return 1;
-	if (alg_id == "FMTSEQ-S256-128") {
-
-		//TODO check it
-	} else if (alg_id == "FMTSEQ-S256-256") {
-
-	} else return 2; //unknown algorithm
 
 	return 0;
 }

src/message.h

@@ -22,6 +22,7 @@
 #include <string>
 #include "bvector.h"
 #include "sencode.h"
+#include "algorithm.h"
 #include "keyring.h"
 #include "prng.h"
 
@@ -31,12 +32,11 @@ public:
 	bvector message;
 	std::string alg_id, key_id;
 
-	int decrypt (bvector&, keyring&);
+	int decrypt (bvector&, algorithm_suite&, keyring&);
 	int encrypt (const bvector& msg,
 	             const std::string& alg_id,
 	             const std::string& key_id,
-	             keyring&, prng&);
-
+	             algorithm_suite&, keyring&, prng&);
 
 	sencode* serialize();
 	bool unserialize (sencode*);
@@ -48,11 +48,11 @@ public:
 	bvector message, signature;
 	std::string alg_id, key_id;
 
-	int verify (keyring&);
+	int verify (algorithm_suite&, keyring&);
 	int sign (const bvector&msg,
 	          const std::string&alg_id,
 	          const std::string&key_id,
-	          keyring&, prng&);
+	          algorithm_suite&, keyring&, prng&);
 
 	sencode* serialize();
 	bool unserialize (sencode*);