1 files changed, 95 insertions, 0 deletions
diff --git a/src/lib/base/key_spec.h b/src/lib/base/key_spec.h
new file mode 100644
index 000000000..78b6b8a23
--- /dev/null
+++ b/src/lib/base/key_spec.h
@@ -0,0 +1,95 @@
+/*
+* Symmetric Key Length Specification
+* (C) 2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_KEY_LEN_SPECIFICATION_H__
+#define BOTAN_KEY_LEN_SPECIFICATION_H__
+
+#include <botan/types.h>
+
+namespace Botan {
+
+/**
+* Represents the length requirements on an algorithm key
+*/
+class BOTAN_DLL Key_Length_Specification
+   {
+   public:
+      /**
+      * Constructor for fixed length keys
+      * @param keylen the supported key length
+      */
+      Key_Length_Specification(size_t keylen) :
+         min_keylen(keylen),
+         max_keylen(keylen),
+         keylen_mod(1)
+         {
+         }
+
+      /**
+      * Constructor for variable length keys
+      * @param min_k the smallest supported key length
+      * @param max_k the largest supported key length
+      * @param k_mod the number of bytes the key must be a multiple of
+      */
+      Key_Length_Specification(size_t min_k,
+                               size_t max_k,
+                               size_t k_mod = 1) :
+         min_keylen(min_k),
+         max_keylen(max_k ? max_k : min_k),
+         keylen_mod(k_mod)
+         {
+         }
+
+      /**
+      * @param length is a key length in bytes
+      * @return true iff this length is a valid length for this algo
+      */
+      bool valid_keylength(size_t length) const
+         {
+         return ((length >= min_keylen) &&
+                 (length <= max_keylen) &&
+                 (length % keylen_mod == 0));
+         }
+
+      /**
+      * @return minimum key length in bytes
+      */
+      size_t minimum_keylength() const
+         {
+         return min_keylen;
+         }
+
+      /**
+      * @return maximum key length in bytes
+      */
+      size_t maximum_keylength() const
+         {
+         return max_keylen;
+         }
+
+      /**
+      * @return key length multiple in bytes
+      */
+      size_t keylength_multiple() const
+         {
+         return keylen_mod;
+         }
+
+      Key_Length_Specification multiple(size_t n) const
+         {
+         return Key_Length_Specification(n * min_keylen,
+                                         n * max_keylen,
+                                         n * keylen_mod);
+         }
+
+   private:
+      size_t min_keylen, max_keylen, keylen_mod;
+   };
+
+}
+
+#endif