Maybe because EVP_PKEY_EC designates an ECDSA key, that an EdDSA key is not generated the same way (particularly the public part), and that the encodings are different? Cordialement, Erwann Abalea Le 15/03/2019 19:20, « openssl-users au nom de Sam Roberts » <openssl-users-bounces@xxxxxxxxxxx au nom de vieuxtech@xxxxxxxxx> a écrit : It seems like they are EC keys, with specific curve designs, and that also have some algorithms designed specifically for them, like EdDSA -- though it looks like that alg is being generalized to other curve types (https://tools.ietf.org/html/rfc8032#ref-EDDSA2). What about them makes it necessary to make them distinct, both from each other, and EVP_PKEY_EC? Thanks, Sam