What is end-to-end encryption?
Encryption where only the phones in a conversation hold the key, like a locked box the post office delivers but can't open.
A message is locked on your phone and unlocked only on the phones it was sent to. Signal, iMessage, WhatsApp and one-to-one Messenger chats work this way. Plain SMS and ordinary Telegram chats don’t.
Before any of that can happen, the phones have to agree on a key, and most apps do that with elliptic-curve cryptography. Someone who records that first exchange today could later work out the key from the recording with a large enough quantum computer. To close that gap, Signal and iMessage now add a post-quantum method to the step where the phones agree on a key.
Related
- Harvest now, decrypt laterRecording encrypted data today to unlock it once a quantum computer can break it. It matters for anything that has to stay secret for decades.
- Post-quantum cryptographyEncryption that runs on ordinary computers but is built to resist quantum computers. For most people, it arrives in an ordinary software update.
- Elliptic-curve cryptographyA kind of encryption that relies on a hard puzzle about points on a curve. It protects most web traffic and the payments made with Bitcoin.