Introduce concept Key.

Chaos/Cipher/Block/Des/DesCrypt.hpp

@@ -10,6 +10,7 @@
 #include "Service/ChaosException.hpp"
 #include "Service/SeArray.hpp"
 
+#include "Cipher/Block/Key.hpp"
 #include "Cipher/Block/Encryptor.hpp"
 #include "Cipher/Block/Decryptor.hpp"
 
@@ -233,6 +234,8 @@ public:
         Inner_::RawKey Key_;
     };
 
+    static_assert(Chaos::Cipher::Block::Key<Key>);
+
     class Encryptor
     {
     public: