1 files changed, 91 insertions, 0 deletions
diff --git a/src/algo_base/sym_algo.h b/src/algo_base/sym_algo.h
new file mode 100644
index 000000000..705c7d00a
--- /dev/null
+++ b/src/algo_base/sym_algo.h
@@ -0,0 +1,91 @@
+/*
+* Symmetric Algorithm Base Class
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_SYMMETRIC_ALGORITHM_H__
+#define BOTAN_SYMMETRIC_ALGORITHM_H__
+
+#include <botan/algo_base.h>
+#include <botan/key_spec.h>
+#include <botan/exceptn.h>
+#include <botan/symkey.h>
+#include <botan/types.h>
+
+namespace Botan {
+
+/**
+* This class represents a symmetric algorithm object.
+*/
+class BOTAN_DLL SymmetricAlgorithm : public Algorithm
+   {
+   public:
+      /**
+      * @return object describing limits on key size
+      */
+      virtual Key_Length_Specification key_spec() const = 0;
+
+      /**
+      * @return minimum allowed key length
+      */
+      size_t maximum_keylength() const
+         {
+         return key_spec().maximum_keylength();
+         }
+
+      /**
+      * @return maxmium allowed key length
+      */
+      size_t minimum_keylength() const
+         {
+         return key_spec().minimum_keylength();
+         }
+
+      /**
+      * Check whether a given key length is valid for this algorithm.
+      * @param length the key length to be checked.
+      * @return true if the key length is valid.
+      */
+      bool valid_keylength(size_t length) const
+         {
+         return key_spec().valid_keylength(length);
+         }
+
+      /**
+      * Set the symmetric key of this object.
+      * @param key the SymmetricKey to be set.
+      */
+      void set_key(const SymmetricKey& key)
+         { set_key(key.begin(), key.length()); }
+
+      /**
+      * Set the symmetric key of this object.
+      * @param key the to be set as a byte array.
+      * @param length in bytes of key param
+      */
+      void set_key(const byte key[], size_t length)
+         {
+         if(!valid_keylength(length))
+            throw Invalid_Key_Length(name(), length);
+         key_schedule(key, length);
+         }
+   private:
+      /**
+      * Run the key schedule
+      * @param key the key
+      * @param length of key
+      */
+      virtual void key_schedule(const byte key[], size_t length) = 0;
+   };
+
+/**
+* The two possible directions for cipher filters, determining whether they
+* actually perform encryption or decryption.
+*/
+enum Cipher_Dir { ENCRYPTION, DECRYPTION };
+
+}
+
+#endif