Selling or acquiring a digital certificate can be done in three different ways:
(1) The BLX Listing Services show all open offers (digital contracts) in an easy to search interface. A second participant can find this offer (digital contract), and begin to fulfill the contract by attaching his part of the obligation. Once both parties sign with their private key, both sides of the digital contract are signed, and the trade automatically executes. If signatures are not provided in a timely manner, the offer is canceled. Such listing services can easily be provided by any participants on the blockchain.
(2) Participants agree between each other, and start the transaction with a contract on their own without using BLX Listing Services. The contract is executed as soon as both parties sign. In this case, both parties must predetermine their expected time to receive a signature on the contract.
In both cases above, the digital certificate or debt-letters tied to any non-executed digital contract remain blocked from any future transactions until the time the contract is executed. When the contract is executed, both parties get their contractually promised certificates sent to their public key. Thus, until the contract is executed and the transaction is logged in the blockchain or canceled, the underlying digital certificates are blocked from further trade. This process will help prevent fraud or bifurcation of the blockchain.
(3) A clearing house takes over the digital certificates, and matches offers to buyers. The main difference is that both parties have already signed their leg of the digital contract and the clearing house is matching them up. If the match is completed, the digital contract is signed by the clearing house, and each party will receive their promised certificate from each leg of the contract by logging it in the blockchain.