code: def extract(input, output):
      
      log("Loading paillier keypair")
      priv = json.load(input)
      error_msg = "Invalid private key"
      assert 'pub' in priv, error_msg
      assert priv['kty'] == 'DAJ', error_msg
      json.dump(priv['pub'], output)
      output.write('\n')
      log("Public key written to {}".format(output.name))
docs: Extract public key from private key.
  
      Given INPUT a private paillier key file as generated by generate, extract the
      public key portion to OUTPUT.
  
      Use "-" to output to stdout.