1 files changed, 61 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/hash/comb4p/comb4p.h b/comm/third_party/botan/src/lib/hash/comb4p/comb4p.h
new file mode 100644
index 0000000000..518314c17d
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+++ b/comm/third_party/botan/src/lib/hash/comb4p/comb4p.h
@@ -0,0 +1,61 @@
+/*
+* Comb4P hash combiner
+* (C) 2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_COMB4P_H_
+#define BOTAN_COMB4P_H_
+
+#include <botan/hash.h>
+
+BOTAN_FUTURE_INTERNAL_HEADER(comb4p.h)
+
+namespace Botan {
+
+/**
+* Combines two hash functions using a Feistel scheme. Described in
+* "On the Security of Hash Function Combiners", Anja Lehmann
+*/
+class BOTAN_PUBLIC_API(2,0) Comb4P final : public HashFunction
+   {
+   public:
+      /**
+      * @param h1 the first hash
+      * @param h2 the second hash
+      */
+      Comb4P(HashFunction* h1, HashFunction* h2);
+
+      size_t hash_block_size() const override;
+
+      size_t output_length() const override
+         {
+         return m_hash1->output_length() + m_hash2->output_length();
+         }
+
+      HashFunction* clone() const override
+         {
+         return new Comb4P(m_hash1->clone(), m_hash2->clone());
+         }
+
+      std::unique_ptr<HashFunction> copy_state() const override;
+
+      std::string name() const override
+         {
+         return "Comb4P(" + m_hash1->name() + "," + m_hash2->name() + ")";
+         }
+
+      void clear() override;
+   private:
+      Comb4P() = default;
+
+      void add_data(const uint8_t input[], size_t length) override;
+      void final_result(uint8_t out[]) override;
+
+      std::unique_ptr<HashFunction> m_hash1, m_hash2;
+   };
+
+}
+
+#endif