Privacy preserving electronic ticket scheme with attribute based credentials

def create_credential_proof(attribute_list, blind_factors, nonce):
  """
  Create a zero-knowledge proof that the prover knows secret key values that
  correspond to the given attributes without revealing those secrets.
  """
  # Generate a nonce (random value)
  # nonce = random.randrange(2**128)
  
  # Commit to the nonce (k)
  blind_nonce = nonce * g
  
  # Commit to the attributes
  blind_attribute_list = [a * g for a in attribute_list]
  
  # Prove knowledge of the secret key values for each attribute
  proof_list = []
  for i in range(len(attribute_list)):
    proof = zkp.dLog_proof(g, blind_attribute_list[i],
                           attribute_list[i], blind_nonce, blind_factors[i], nonce)
    proof_list.append(proof)
  
  proof_tuple = tuple(proof_list)
  
  return