Читать книгу Cryptocurrency Mining For Dummies - Peter Kent - Страница 32

So, here’s how cryptography is used when you want to send a transaction to the blockchain, to transfer a cryptocurrency balance to another person. Say there’s an address in the blockchain with Bitcoin associated with it. When I checked, 1L7hHWfJL1dd7ZhQFgRv8ke1PTKAHoc9Tq had a balance of 0.10701382 Bitcoin. Now, say this is your Bitcoin, and you want to send, perhaps, 0.05 Bitcoin to a friend, an exchange, or a merchant from whom you are buying a good or service.

The address I use in this example is a real address; you can see it for yourself in a blockchain explorer. (Use this link to get to it: https://blockstream.info/address/1L7hHWfJL1dd7ZhQFgRv8ke1PTKAHoc9Tq.) At the time of writing, it had 0.10701382 Bitcoin. By the time you see it, the number may be different, of course.

You send a message to the blockchain saying, essentially, “I own address 1L7hHWfJL1dd7ZhQFgRv8ke1PTKAHoc9Tq, and I want to send 0.05 Bitcoin to address 1NdaT7URGyG67L9nkP2TuBZjYV6yL7XepS.”

If I just sent a plaintext (unencrypted) message to the blockchain, there would be a huge problem of verification and validity. How would the Bitcoin node receiving this message know that I do indeed own this address and the money associated with it? I could just be spoofing this information and making this up, right?

What we do is use the wallet to sign the message using the private key associated with the address. In other words, we use the private key to encrypt the message. Then we take the public key, add it to the encrypted message, and send it all out across the cryptocurrency network.