BAC-L0-FOUND-105
Public keys, private keys, signatures
Asymmetric cryptography as a mechanism of authority: what a signature proves, who can produce one, and why the private key is the identity itself.
- Level
- L0 — Foundation
- Duration
- 3 h
- Track
- Foundation
- Maintainer
- Developer Curriculum Architect
Learning objectives
- 01Generate a key pair and sign a message a third party can verify
- 02Explain the difference between signing and encrypting
- 03Describe what happens, irreversibly, when a private key leaks
Guided lab
Sign and verify messages with ed25519, then forge a signature and watch verification fail.
Independent lab
Write an independent signature verifier without reusing the demonstration code.
Security angle
Two signatures over one nonce: show how a faulty random generator exposes the private key.
Assessment
Working verifier, tested against supplied test vectors.