1 files changed, 115 insertions, 0 deletions
diff --git a/src/aead/ocb/ocb.h b/src/aead/ocb/ocb.h
new file mode 100644
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+++ b/src/aead/ocb/ocb.h
@@ -0,0 +1,115 @@
+/*
+* OCB Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_OCB_H__
+#define BOTAN_OCB_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/buf_filt.h>
+#include <memory>
+
+namespace Botan {
+
+class L_computer;
+class Nonce_State;
+
+/**
+* OCB Mode (base class for OCB_Encryption and OCB_Decryption). Note
+* that OCB is patented, but is freely licensed in some circumstances.
+*
+* @see "The OCB Authenticated-Encryption Algorithm" internet draft
+        http://tools.ietf.org/html/draft-irtf-cfrg-ocb-00
+* @see Free Licenses http://www.cs.ucdavis.edu/~rogaway/ocb/license.htm
+* @see OCB home page http://www.cs.ucdavis.edu/~rogaway/ocb
+*/
+class BOTAN_DLL OCB_Mode : public AEAD_Mode
+   {
+   public:
+      secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override;
+
+      size_t update_granularity() const;
+
+      Key_Length_Specification key_spec() const override;
+
+      bool valid_nonce_length(size_t) const override;
+
+      void clear();
+
+      ~OCB_Mode();
+   protected:
+      static const size_t BS = 16; // intrinsic to OCB definition
+
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Mode(BlockCipher* cipher, size_t tag_size);
+
+      void key_schedule(const byte key[], size_t length) override;
+
+      size_t tag_size() const { return m_tag_size; }
+
+      // fixme make these private
+      std::unique_ptr<BlockCipher> m_cipher;
+      std::unique_ptr<L_computer> m_L;
+
+      size_t m_tag_size = 0;
+      size_t m_block_index = 0;
+
+      secure_vector<byte> m_ad_hash;
+      secure_vector<byte> m_offset;
+      secure_vector<byte> m_checksum;
+   private:
+      std::unique_ptr<Nonce_State> m_nonce_state;
+   };
+
+class BOTAN_DLL OCB_Encryption : public OCB_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
+         OCB_Mode(cipher, tag_size) {}
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks) override;
+
+      void finish(secure_vector<byte>& final_block) override;
+   private:
+      void encrypt(byte input[], size_t blocks);
+   };
+
+class BOTAN_DLL OCB_Decryption : public OCB_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
+         OCB_Mode(cipher, tag_size) {}
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks) override;
+
+      void finish(secure_vector<byte>& final_block) override;
+   private:
+      void decrypt(byte input[], size_t blocks);
+   };
+
+}
+
+#endif