SSLCertificate.py
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from OpenSSL import crypto, SSL


def create_self_signed_cert(cert_file, key):
    cert = crypto.X509()
    cert.set_serial_number(1001)
    cert.set_notBefore(b'20190101000000Z')
    cert.set_notAfter(b'20290101000000Z')
    subject = cert.get_subject()
    subject.C = "NO"
    subject.ST = "Aust-Agder"
    subject.L = "Grimstad"
    subject.OU = "UiA"
    subject.CN = "localhost"
    cert.set_issuer(subject)
    cert.set_pubkey(key)
    cert.sign(key, "SHA256")
    write_to_file(crypto.dump_certificate(crypto.FILETYPE_PEM, cert),cert_file)
    return cert



def write_to_file(data, filename):
    file = open(filename, "wb")
    file.write(data)
    file.close()


def create_public_key_pair(key_file):
    k = crypto.PKey()
    k.generate_key(crypto.TYPE_RSA, 4096)
    write_to_file(crypto.dump_privatekey(crypto.FILETYPE_PEM, k), key_file)
    return k

if __name__ == "__main__":
    k=create_public_key_pair("example.key")
    create_self_signed_cert("example.crt", k)