1 files changed, 51 insertions, 0 deletions
diff --git a/src/lib/prf/hkdf/hkdf.h b/src/lib/prf/hkdf/hkdf.h
new file mode 100644
index 000000000..e0b5a7376
--- /dev/null
+++ b/src/lib/prf/hkdf/hkdf.h
@@ -0,0 +1,51 @@
+/*
+* HKDF
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_HKDF_H__
+#define BOTAN_HKDF_H__
+
+#include <botan/mac.h>
+#include <botan/hash.h>
+#include <memory>
+
+namespace Botan {
+
+/**
+* HKDF, see @rfc 5869 for details
+*/
+class BOTAN_DLL HKDF
+   {
+   public:
+      HKDF(MessageAuthenticationCode* extractor,
+           MessageAuthenticationCode* prf) :
+         m_extractor(extractor), m_prf(prf) {}
+
+      HKDF(MessageAuthenticationCode* prf) :
+         m_extractor(prf), m_prf(m_extractor->clone()) {}
+
+      void start_extract(const byte salt[], size_t salt_len);
+      void extract(const byte input[], size_t input_len);
+      void finish_extract();
+
+      /**
+      * Only call after extract
+      * @param output_len must be less than 256*hashlen
+      */
+      void expand(byte output[], size_t output_len,
+                  const byte info[], size_t info_len);
+
+      std::string name() const;
+
+      void clear();
+   private:
+      std::unique_ptr<MessageAuthenticationCode> m_extractor;
+      std::unique_ptr<MessageAuthenticationCode> m_prf;
+   };
+
+}
+
+#endif