Abstract: An over-the-counter (OTC) transaction system comprising a computing device operable to send a transaction request to initiate a transaction; and a server operable to receive an OTC electronic transaction request from a computing device and thereafter generate a unique identifier based on the transaction request received from the computing device as part of the transaction; the server further operable to verify the transaction based on the generated unique identifier; and upon verification, process and inform the computing device a status of the transaction; wherein the verification includes comparing a portion of the unique identifier with the entries in a whitelist maintained by the server; and wherein the unique identifier is temporary and is configured to expire after a predetermined criteria is met.