@Wanderer18 30 April 2021 more from that month

A follow up to my previous post regarding paytaca, i can't wait for it be launched fully. The app can now be downloaded though it is still in development. Let's help in completing this project by giving our feedbacks and suggestions to the developers team. How do paytaca facilitate offline payments? We use 2-of-2 Schnorr multi-signature address, one key held by the user and another key held by the server. An offline transaction is created from pre-fetched UTXOs, then it is partially signed by the user’s key. Merchant wallet or POS is able to scan this partially signed transaction from a QR code presented by the user’s wallet. Without broadcasting this to the server and even in offline mode, it’s able to verify if the partial signature is valid. If the merchant is online, it can instantly send this to the server. The server then checks the transaction and provides the second signature to form the final combined signature which will make the transaction valid. It is then broadcast to the blockchain. In this scenario, there is no risk of double spending since settlement is immediate (assuming zero-conf). If the merchant is offline, the wallet allows merchants to accept the partially signed transaction as "proof of payment” as long as the partial signature is valid. The merchant wallet/POS then broadcasts this transaction later when internet connection is resumed. Source: https://devpost.com/software/paytaca#updates #BitcoinCash