Encryption in Messaging Apps
Explore how Signal, WhatsApp, and iMessage use end-to-end encryption to keep your conversations private.
What Is End-to-End Encryption?
End-to-end encryption (E2E) means that messages are encrypted on the sender's device and can only be decrypted on the recipient's device. No server in the middle, not even the messaging platform itself, can read your messages.
This is a fundamental shift from older systems where the provider held the keys and could technically read all messages.
The Signal Protocol
WhatsApp, Signal, and many other apps use the Signal Protocol, originally developed by Open Whisper Systems. It combines several cryptographic techniques including the Double Ratchet Algorithm and X3DH (Extended Triple Diffie-Hellman) key agreement.
The protocol provides forward secrecy, meaning that even if one session key is compromised, past messages remain secure.
All lessons in this course
- Encryption in Messaging Apps
- How Banks Protect Your Transactions
- The Internet Without Cryptography
- Your Digital Life and Cryptography