Generate x25519 certificate

generate_x25519.py

#!/usr/bin/env python
import datetime as dt

from cryptography import x509
from cryptography.hazmat.backends.openssl import backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ed25519, x25519
from cryptography.x509.oid import NameOID

issuer_private_key = ed25519.Ed25519PrivateKey.generate()
subject_private_key = x25519.X25519PrivateKey.generate()

not_valid_before = dt.datetime(2022, 1, 1, 12, 1)
not_valid_after = dt.datetime(2040, 12, 31, 8, 30)

builder = (
    x509.CertificateBuilder()
    .serial_number(777)
    .issuer_name(x509.Name([x509.NameAttribute(NameOID.COUNTRY_NAME, "HU")]))
    .subject_name(x509.Name([x509.NameAttribute(NameOID.COUNTRY_NAME, "HU")]))
    .public_key(subject_private_key.public_key())
    .not_valid_before(not_valid_before)
    .not_valid_after(not_valid_after)
)

cert = builder.sign(issuer_private_key, None, backend)

print(cert.public_bytes(serialization.Encoding.PEM).decode())