Move EAX to new AEAD_Mode interface

1 files changed, 81 insertions, 0 deletions

diff --git a/src/aead/aead.h b/src/aead/aead.h
new file mode 100644
index 000000000..af6f0e76a
--- /dev/null
+++ b/src/aead/aead.h
@@ -0,0 +1,81 @@
+/*
+* Interface for AEAD modes
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_MODE_H__
+#define BOTAN_AEAD_MODE_H__
+
+#include <botan/sym_algo.h>
+
+namespace Botan {
+
+/**
+* Interface for AEAD (Authenticated Encryption with Associated Data)
+* modes. These modes provide both encryption and message
+* authentication, and can authenticate additional per-message data
+* which is not included in the ciphertext (for instance a sequence
+* number).
+*/
+class AEAD_Mode : public SymmetricAlgorithm
+   {
+   public:
+      /**
+      * @return size of required blocks to update
+      */
+      virtual size_t update_granularity() const = 0;
+
+      /**
+      * @return required minimium size to finalize() - may be any
+      *         length larger than this.
+      */
+      virtual size_t minimum_final_size() const = 0;
+
+      /**
+      * Set associated data that is not included in the ciphertext but
+      * that should be authenticated. Must be called after set_key
+      * and before end_msg.
+      *
+      * Unless reset by another call, the associated data is kept
+      * between messages. Thus, if the AD does not change, calling
+      * once (after set_key) is the optimum.
+      *
+      * @param ad the associated data
+      * @param ad_len length of add in bytes
+      */
+      virtual void set_associated_data(const byte ad[], size_t ad_len) = 0;
+
+      virtual bool valid_nonce_length(size_t) const = 0;
+
+      /**
+      * Begin processing a message.
+      *
+      * @param nonce the per message nonce
+      * @param nonce_len length of nonce
+      */
+      virtual secure_vector<byte> start(const byte nonce[], size_t nonce_len) = 0;
+
+      /**
+      * Update (encrypt or decrypt) some data. Input must be in size
+      * update_granularity() byte blocks.
+      * @param blocks in/out paramter which will possibly be resized
+      */
+      virtual void update(secure_vector<byte>& blocks) = 0;
+
+      /**
+      * Complete processing of a message. For decryption, may throw an exception
+      * due to authentication failure.
+      *
+      * @param final_block in/out parameter which must be at least
+      *        minimum_final_size() bytes, and will be set to any final output
+      */
+      virtual void finish(secure_vector<byte>& final_block) = 0;
+
+      virtual ~AEAD_Mode() {}
+   };
+
+}
+
+#endif