* cipher/pubkey.c (pubkey_encrypt): Fold into gcry_pk_encrypt.
(pubkey_decrypt): Fold into gcry_pk_decrypt.
(pubkey_sign): Fold into gcry_pk_sign.
(pubkey_verify): Fold into gcry_pk_verify.
(octet_string_from_mpi): Make it a wrapper and factor code out to ...
* mpi/mpicoder.c (_gcry_mpi_to_octet_string): New function.
* src/cipher.h (PUBKEY_FLAG_FIXEDLEN): New.
* cipher/pubkey.c (sexp_data_to_mpi): Set flag for some encodings.
(gcry_pk_encrypt): Simply by moving the s-expr generation to the modules.
(gcry_pk_sign): Ditto.
* cipher/dsa.c (dsa_sign): Create s-expr.
* cipher/elgamal.c (elg_encrypt, elg_sign): Ditto.
* cipher/rsa.c (rsa_encrypt, rsa_sign): Ditto.
* cipher/ecc.c (ecc_sign, ecc_encrypt_raw): Ditto.
(ecdsa_names): Add "eddsa".
* tests/t-ed25519.c (one_test): Expect "eddsa" token.