What is End-to-End Encryption?
We all need to feel secure when we share our private thoughts with other people. Even if it's just a mundane conversation, we feel better knowing no one is listening in. That goes double on the internet when you have no idea who could be monitoring your chat with your crush or your conversation with your boss. This is where end-to-end encryption comes in. Anything can be encrypted with end-to-end encryption, not just messages, so you can safely send pictures, videos, documents, audio files etc.
Any software using end-to-end encryption (E2EE) guarantees that only you and the recipient can see what's been sent. Nobody can intercept your messages while they're being transmitted and read them. Not even the app you're using itself. Only you and the person you're communicating with have the security keys necessary to lock and unlock the messages. All of this is done automatically, of course. There's no need for any input on your part.
By design end-to-end encryption blocks everyone, even your telecom and internet providers from eavesdropping on your conversations. The method is so secure that companies that employ end-to-end encryption cannot hand over any messages to the authorities in case of an investigation for that reason.
How does it work?
The encryption keys used to encrypt and decrypt your messages are stored entirely on the endpoints of the conversation, meaning you and whoever you're talking to. This is possible thanks to public key encryptions. Public keys are large numeric values used to encrypt information. They can be pre-assigned or generated on the spot. Either way, the keys are created by software or provided by a known, trusted source.
E2EE is currently considered unbreakable by existing algorithms, but it's not foolproof. If either endpoint is compromised it can render the whole thing worthless. Also, if the provider of the keys is either compromised or hostile E2EE becomes moot.
What are the uses of E2EE?
The first and most important advantage is that E2EE keeps your private info safe from hostile third parties. With end-to-end encryption, only you and the person you're chatting with can see the contents of your messages. Even if the servers get hacked you're still safe because your messages can't be read without the correct encryption keys.
The second big advantage of E2EE is that it can keep your private life, well, private. It's a fact all these big social media platforms are spying on us. If the Facebook/Cambridge Analytica fiasco wasn't enough to convince you just consider that every message, picture, video, or document you ever uploaded anywhere was stored on a server. Anyone working for the provider could access it. With end-to-end encryption, you can eliminate that fear.
Third, it protects our rights. We all consider it our God-given right to say what we believe, but that doesn't mean other people won't try to stop us. With E2EE journalists and political dissidents can do their work without fear of being exposed and subjected to threats and attacks.