The Keypair trait not usable for keys not implementing the Signer trait. For example, I looked upon implementing it for the new RSA key structures. Implementing the Keypair for the pkcs1v15::SigningKey involves some pain, put should be possible. For the pss::SigningKey the Keypair can not be implemented at all, since the PSS keys only implement the RandomizedSigner and RandomizedVerified traits.
The
Keypairtrait not usable for keys not implementing theSignertrait. For example, I looked upon implementing it for the new RSA key structures. Implementing theKeypairfor thepkcs1v15::SigningKeyinvolves some pain, put should be possible. For thepss::SigningKeytheKeypaircan not be implemented at all, since the PSS keys only implement theRandomizedSignerandRandomizedVerifiedtraits.