Sending and receiving crypto

Sending crypto takes seconds and cannot be undone. Almost every loss at this stage comes from a wrong address or a wrong network. This lesson builds the habits that prevent both.

Receiving

1. Open your wallet and tap "receive".
2. Choose the coin and, where asked, the network.
3. Share the address as text or as a QR code.

Sharing an address is safe. Tell the sender which network you expect. A Bitcoin wallet shows a new address each time, and all of them are yours.

Sending

1. Get the recipient's address directly from them, as text or a QR code.
2. Paste or scan it into your wallet. Never type it by hand.
3. Choose the same network the recipient is using.
4. Enter the amount.
5. Review the address, amount, network and fee.
6. Confirm.

bitcoin.org states the stakes plainly: a transaction "cannot be reversed, it can only be refunded by the person receiving the funds".

Check the address properly

Addresses are long, and people check only the first and last few characters. Two attacks rely on that.

Clipboard malware. Malicious software watches for a copied address and swaps in the attacker's own when you paste. After pasting, compare what appears in your wallet with the original, including characters in the middle.

Address poisoning. An attacker creates an address that matches the start and end of one you use. They send you a tiny or zero-value transaction so their address appears in your history. Later you copy it from your history by mistake.

Researchers at Carnegie Mellon University counted about 270 million of these attempts on two networks between July 2022 and June 2024. Confirmed losses were at least $83.8 million.

The defences are simple:

• Never copy an address from your transaction history.
• Save addresses you use often in your wallet's address book.
• Ignore small deposits you did not expect.
• On a hardware wallet, read the address on the device's screen.

Send a test first

For any large payment or new address, send a small amount first. Wait until the recipient confirms it arrived. Then send the rest. The extra fee is small next to the cost of a mistake.

Waiting for confirmation

A sent transaction shows as pending until the network includes it in a block. Lesson 3 explained confirmations. Exchanges wait for several before crediting a deposit, which can take from seconds to an hour depending on the network.

Details that catch people out

• Memos and tags. Some coins need an extra code when you deposit to an exchange. If the exchange shows one, include it.
• Minimum amounts. Exchanges may ignore deposits below a minimum.
• Fees. You need some of the network's own coin to pay the fee. Lesson 32 covers this.