1 files changed, 90 insertions, 0 deletions
diff --git a/src/hmac.cpp b/src/hmac.cpp
new file mode 100644
index 000000000..1cac5faa2
--- /dev/null
+++ b/src/hmac.cpp
@@ -0,0 +1,90 @@
+/*************************************************
+* HMAC Source File                               *
+* (C) 1999-2006 The Botan Project                *
+*************************************************/
+
+#include <botan/hmac.h>
+#include <botan/lookup.h>
+#include <botan/bit_ops.h>
+
+namespace Botan {
+
+/*************************************************
+* Update a HMAC Calculation                      *
+*************************************************/
+void HMAC::add_data(const byte input[], u32bit length)
+   {
+   hash->update(input, length);
+   }
+
+/*************************************************
+* Finalize a HMAC Calculation                    *
+*************************************************/
+void HMAC::final_result(byte mac[])
+   {
+   hash->final(mac);
+   hash->update(o_key);
+   hash->update(mac, OUTPUT_LENGTH);
+   hash->final(mac);
+   hash->update(i_key);
+   }
+
+/*************************************************
+* HMAC Key Schedule                              *
+*************************************************/
+void HMAC::key(const byte key[], u32bit length)
+   {
+   hash->clear();
+   std::fill(i_key.begin(), i_key.end(), 0x36);
+   std::fill(o_key.begin(), o_key.end(), 0x5C);
+
+   SecureVector<byte> hmac_key(key, length);
+   if(hmac_key.size() > hash->HASH_BLOCK_SIZE)
+      hmac_key = hash->process(hmac_key);
+
+   xor_buf(i_key, hmac_key, hmac_key.size());
+   xor_buf(o_key, hmac_key, hmac_key.size());
+   hash->update(i_key);
+   }
+
+/*************************************************
+* Clear memory of sensitive data                 *
+*************************************************/
+void HMAC::clear() throw()
+   {
+   hash->clear();
+   i_key.clear();
+   o_key.clear();
+   }
+
+/*************************************************
+* Return the name of this type                   *
+*************************************************/
+std::string HMAC::name() const
+   {
+   return "HMAC(" + hash->name() + ")";
+   }
+
+/*************************************************
+* Return a clone of this object                  *
+*************************************************/
+MessageAuthenticationCode* HMAC::clone() const
+   {
+   return new HMAC(hash->name());
+   }
+
+/*************************************************
+* HMAC Constructor                               *
+*************************************************/
+HMAC::HMAC(const std::string& hash_name) :
+   MessageAuthenticationCode(output_length_of(hash_name),
+                             1, 2*block_size_of(hash_name)),
+   hash(get_hash(hash_name))
+   {
+   if(hash->HASH_BLOCK_SIZE == 0)
+      throw Invalid_Argument("HMAC cannot be used with " + hash->name());
+   i_key.create(hash->HASH_BLOCK_SIZE);
+   o_key.create(hash->HASH_BLOCK_SIZE);
+   }
+
+}