Yes or No, determined by the method they transact.
Bob’s wallet need to do something
No matter how they transaction, Bob’ wallet should do something to make transaction, which means Bob should be online to receive coins. Because both Alice and Bob’s private key should be used to finish the transaction. It’s different from Bitcoin, which only need sender’s private key to finish transaction. It’s determined by the mechanism of MimbleWimble.
Grin wallet
With original Grin wallet, there’re 2 ways to make transactions:
- Sending file: Bob needs to receive coins manually. He needs to receive the transaction file from Alice, generates a response file, and send it back to Alice. This process is described in Vite’s inviting Beta tester for Grin wallet!
- HTTP: Bob’s wallet can receive coins automatically. Bob’s Grin wallet listen to a port. Whenever Alice sends the transaction file to this port, Bob’s wallet automatically receives the transaction file, generate a response file, and send it back. But it needs a static IP address and your client should work continually.
Grinbox
Grinbox make things much easier. The wallet’s CLI client is called wallet713, server side is called grinbox. Grinbox server records users’ IP address and public address, and act as a proxy of sending transaction files back and forth, so users can finish the transaction processes automatically without static IP address. Grinbox server and Alice, Bob’s wallet713 clients cooperate to make transaction automatically.
If both Alice and Bob run wallet713 at the same time, then Alice can send coins to Bob just by specifying Bob’s public address, the experience is like Bitcoin.
grinpurse is similar to grinbox, it has a GUI client.