Such an electronic cash exchange system assumes that the three parties involved in it, i.e. the bank, the client and the seller, are completely independent of one another. Thus the system must guarantee to each party that it will not be cheated,
even if the other two parties are acting in bad faith and in collusion. In addition, every one of the three stages, i.e. the creation, spending and cashing of the notes can be executed separately. Hence every one of these stages requires a different special protocol. The notes held by the client after it finishes communicating with the bank are called electronic cash due to their guaranteed anonymity, just as paper cash is anonymous. After it is spent at the second stage, the seller holds certificates of the transaction which it presents to the bank any time after finishing its communications with the client.