ed25519 digital signature methods in PostgreSQL via PL/Python

ed25519.sql

CREATE EXTENSION IF NOT EXISTS plpythonu;

CREATE FUNCTION py_create_ed25519_keypair ()
  RETURNS varchar[]
AS $$
  import axolotl_curve25519 as curve
  import os
  import base64

  randm32 = os.urandom(32)
  private_key = curve.generatePrivateKey(randm32)
  public_key = curve.generatePublicKey(private_key)
  return [base64.b64encode(private_key), base64.b64encode(public_key)]
$$ LANGUAGE plpythonu;

CREATE FUNCTION py_create_ed25519_signature (message varchar, private_key varchar)
  RETURNS varchar
AS $$
  import axolotl_curve25519 as curve
  import os
  import base64
  randm64 = os.urandom(64)
  signature = curve.calculateSignature(randm64, base64.b64decode(private_key), message)
  return base64.b64encode(signature)
$$ LANGUAGE plpythonu;

CREATE FUNCTION py_verify_ed25519_signature (message varchar, signature varchar, public_key varchar)
  RETURNS boolean
AS $$
  import axolotl_curve25519 as curve
  import base64
  valid = (curve.verifySignature(base64.b64decode(public_key), message, base64.b64decode(signature)) == 0)
  return valid
$$ LANGUAGE plpythonu;