X.509 certificate based on Daniel J. Bernstein’s Curve25519 (as per RFC 8410).
$ openssl req -x509 -newkey ed25519 -keyout test.key -out test.cer -days 3652 -subj '/C=IT/L=Milano/CN=Test ed25519'
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----