Science & TechMental model
Encryption explained with an open padlock.
Imagine handing out open padlocks that only your key can open. Anyone can lock a box with one, but only you can unlock it. The padlock is your public key, the key is your private key. That's asymmetric cryptography, the foundation of nearly all secure communication since 1976.
Useful: That's why you can show your public key to anyone: it can only lock, never unlock.
Source: en.wikipedia.org