TinkerBrightwater’s invoice, not yet sealed. Toy-size numbers.
Chapter 4 of 7
Sealed with your key
Brightwater’s invoice arrives with bank details. Anyone can close its padlock, so who really wrote this?
This chapter: How does a signature prove who wrote a message, and that nobody changed it?
About this chapter
You will learn
- Sign with the private key
- Anyone checks with the public key
- One changed byte breaks the seal
Words you’ll meet
- Signature
- A seal only the private key can make, and anyone can check with the public key.
- Verify
- Check a signature against the message and the signer’s public key.
Step 1 of 4
A runs the padlock backwards: only the private key makes it, anyone checks it with the public key.
Sign the invoice.
“Invoice 1207: pay 1880.00 to account 4417-2209.”