3 files changed, 90 insertions, 0 deletions
diff --git a/src/lib/kdf/sp800_56c/info.txt b/src/lib/kdf/sp800_56c/info.txt
new file mode 100644
index 000000000..203c05a83
--- /dev/null
+++ b/src/lib/kdf/sp800_56c/info.txt
@@ -0,0 +1,6 @@
+define SP800_56C 20160211
+
+<requires>
+sp800_108
+hmac
+</requires>
diff --git a/src/lib/kdf/sp800_56c/sp800_56c.cpp b/src/lib/kdf/sp800_56c/sp800_56c.cpp
new file mode 100644
index 000000000..664d32b30
--- /dev/null
+++ b/src/lib/kdf/sp800_56c/sp800_56c.cpp
@@ -0,0 +1,45 @@
+/*
+* KDF defined in NIST SP 800-56c
+* (C) 2016 Kai Michaelis
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/sp800_108.h>
+#include <botan/sp800_56c.h>
+#include <botan/hmac.h>
+
+namespace Botan {
+
+SP800_56C* SP800_56C::make(const Spec& spec)
+   {
+   if(auto exp = SP800_108_Feedback::make(spec))
+      {
+      if(auto mac = MessageAuthenticationCode::create(spec.arg(0)))
+         return new SP800_56C(mac.release(), exp);
+
+      if(auto mac = MessageAuthenticationCode::create("HMAC(" + spec.arg(0) + ")"))
+         return new SP800_56C(mac.release(), exp);
+      }
+
+   return nullptr;
+   }
+
+size_t SP800_56C::kdf(byte key[], size_t key_len,
+                      const byte secret[], size_t secret_len,
+                      const byte salt[], size_t salt_len) const
+   {
+      // Randomness Extraction
+      secure_vector< byte > k_dk, context;
+
+      m_prf->set_key(salt, salt_len);
+      m_prf->update(secret, secret_len);
+      m_prf->final(k_dk);
+
+      // Key Expansion
+      m_exp->kdf(key, key_len, k_dk.data(), k_dk.size(), context.data(), context.size());
+
+   return key_len;
+   }
+
+}
diff --git a/src/lib/kdf/sp800_56c/sp800_56c.h b/src/lib/kdf/sp800_56c/sp800_56c.h
new file mode 100644
index 000000000..d1b6f39b5
--- /dev/null
+++ b/src/lib/kdf/sp800_56c/sp800_56c.h
@@ -0,0 +1,39 @@
+/*
+* KDF defined in NIST SP 800-56c
+* (C) 2016 Kai Michaelis
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_SP800_56C_H__
+#define BOTAN_SP800_56C_H__
+
+#include <botan/kdf.h>
+#include <botan/mac.h>
+
+namespace Botan {
+
+/**
+ * NIST SP 800-56C KDF
+ */
+class BOTAN_DLL SP800_56C : public KDF
+   {
+   public:
+      std::string name() const override { return "SP800-56C(" + m_prf->name() + ")"; }
+
+      KDF* clone() const override { return new SP800_56C(m_prf->clone(), m_exp->clone()); }
+
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
+
+      SP800_56C(MessageAuthenticationCode* mac, KDF* exp) : m_prf(mac), m_exp(exp) {}
+
+      static SP800_56C* make(const Spec& spec);
+   private:
+      std::unique_ptr<MessageAuthenticationCode> m_prf;
+      std::unique_ptr<KDF> m_exp;
+   };
+}
+
+#endif