The user device is first placed into a primed state, ready to sign inbound transactions using its secure element. In this mode, it can receive unsigned payloads and sign them without exposing private keys. The merchant device constructs the transaction, including the network parameters, recipent address and USDC amount. Once prepared, the unsigned transaction is broadcast to the user device via NFC, where it is signed locally and returned as a signed payload. With the signature attached, the merchant device completes the transaction and submits it to the Solana mainnet. It then retrieves the transaction ID and confirms network acceptance.