Add Comb4P hash combiner, as described in Anja Lehmann's thesis.

1 files changed, 47 insertions, 0 deletions

diff --git a/src/hash/comb4p/comb4p.h b/src/hash/comb4p/comb4p.h
new file mode 100644
index 000000000..ce66bb9c9
--- /dev/null
+++ b/src/hash/comb4p/comb4p.h
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+/**
+* Comb4P hash combiner
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_COMB4P_H__
+#define BOTAN_COMB4P_H__
+
+#include <botan/hash.h>
+
+namespace Botan {
+
+/**
+* Combines two hash functions using a Feistel scheme. Described in
+* "On the Security of Hash Function Combiners", Anja Lehmann
+*/
+class Comb4P : public HashFunction
+   {
+   public:
+      Comb4P(HashFunction* h1, HashFunction* h2);
+
+      ~Comb4P() { delete hash1; delete hash2; }
+
+      HashFunction* clone() const
+         {
+         return new Comb4P(hash1->clone(), hash2->clone());
+         }
+
+      std::string name() const
+         {
+         return "Comb4P(" + hash1->name() + "," + hash2->name() + ")";
+         }
+
+      void clear();
+   private:
+      void add_data(const byte input[], u32bit length);
+      void final_result(byte out[]);
+
+      HashFunction* hash1;
+      HashFunction* hash2;
+   };
+
+}
+
+#endif