Lion Cipher Lab
Encrypt and sign with GPG (public-key crypto you can use today)
- Identity & Access Management
- Beginner
- ~45-60 min
- Free · no account required
Why it matters
Two everyday problems have the same answer, and GPG is it. The first is privacy: you want to send a file or note so that ONLY one specific person can read it, even if it passes through email servers, cloud storage, or a USB stick along the way. The second, which most people never learn, is authenticity: you want a reader to be able to PROVE that a file, a message, or a piece of software really came from you and was not tampered with in transit. Public-key cryptography solves both with one idea -- a matched pair of keys. Your PUBLIC key is safe to hand out to the whole world; your PRIVATE key…
What you'll learn
- what public-key cryptography is in plain terms: a public key you share and a private key you guard
- installing GnuPG (GPG) on Windows, macOS, or Linux from the official source
- generating your own key pair with a strong passphrase, and reading your key's fingerprint
- exporting your PUBLIC key and publishing it (to a file and to a keyserver) so others can write to you
- importing someone else's public key and verifying it by fingerprint before trusting it
- encrypting a file so ONLY the intended recipient can open it, and decrypting one sent to you
- cryptographically SIGNING a file or message, and VERIFYING a signature to prove author + integrity
- the difference between encrypting (privacy) and signing (authenticity) and which key does each
- the web of trust: how PGP validates keys without a central authority
- protecting the private key and passphrase, setting key expiry, and making a revocation certificate in advance
Steps in this lab
- The one big idea: two keys, and what each one is for
- Open a terminal and install GnuPG
- Generate your own key pair
- Make a revocation certificate NOW, before you ever need it
- Export and publish your PUBLIC key so others can write to you
- Import a recipient's public key and verify it by fingerprint
- Encrypt a file for a recipient, and decrypt one sent to you
- Sign a file or message, and verify a signature
- Key management and the habits that keep you safe
- My take: learn signing, not just encryption