From: Thomas DuBuisson

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class (Binary p, Serialize p) => AsymCipher p where generateKeypair :: RandomGen g => g -> BitLength -> Maybe ((p,p),g) encryptAsym :: p -> B.ByteString -> B.ByteString decryptAsym :: p -> B.ByteString -> B.ByteString asymKeyLength :: p -> BitLength

Regarding AsymCipher: Some algorithms do not lend themselves to encryption/decryption or have special properties which differentiate their use in enc/dec an signing/verifying.

I propose the following two additions for the class: signAsym :: p -> B.ByteString -> B.ByteString verifyAsym :: p -> B.ByteString -> Bool

This way algorithms can leave parts undefined which do not apply to them or hide their different behaviour.

I am strongly against classes for which we already know instanes will need a good deal of undefined routines.

I agree. However, you could just make separate type class for these methods. John Lato