Why is end-to-end encryption important in the digital age?

The Reality of Digital Communication

We have the usual impression that we send private messages only to the relevant contact. The reality is somewhat different – your data passes through central servers, where it remains stored. None of us would wish for the service provider, which acts as a bridge between you and the recipient, to have access to the content of your communication. It is precisely at this point that end-to-end encryption comes into play.

End-to-end encryption ensures that only the sender and intended recipient have the ability to read the message. This protected communication can contain anything from text messages to files to video calls. The history of this technology dates back to the 1990s when programmer Phil Zimmerman released Pretty Good Privacy, abbreviated as PGP.

How We Commonly Communicate Without Encryption

On a typical messaging platform, the user first registers, creating an account for communication. When you write a message and send it to a friend, the data first goes to the provider's server. It identifies the recipient and forwards the message.

This model is called client-server architecture. Your phone (client) acts only as an interface, while the server does all the work. This also means that the service provider is an intermediary in all your communications.

Communication typically passes through two encrypted segments – from the client to the server (A ↔ S) and from the server to the recipient (S ↔ B). Protocols like TLS (Transport Layer Security) are used for this purpose, which protect the data during transmission. However, such a solution does not prevent the servers themselves from reading your messages – it only protects their path.

Once the data settles on the server in a database among millions of other pieces of information, it becomes a vulnerable target. The history of major data breaches repeatedly demonstrates how devastating this can be for end users.

How End-to-End Encryption Works

End-to-end encryption ensures protection from the beginning to the end of communication – without access for servers or external parties. Applications like WhatsApp, Signal, or Google Duo protect their users in this way.

The technological process begins with what is called key exchange.

Key Exchange – Diffie-Hellman Method

This technique was invented by cryptographers Whitfield Diffie, Martin Hellman, and Ralph Merkle. Its purpose is to allow two parties to create a shared secret even in a hostile environment – on an unsecured channel, if you will, under the watchful eyes of spectators, without compromising the security of later messages.

To illustrate this, we can use the common analogy with colors. Imagine Alice and Bob sitting in separate rooms, wanting to create a unique color that the other does not know. Their problem: spies are guarding the hallway.

Alice and Bob first publicly agree on a common color – for example, yellow. They can share it in the hallway without worry. In the safety of their rooms, each then adds their secret color – Alice a shade of blue, Bob red. Key detail: spies will not see these secret colors.

Then Alice and Bob exchange their new mixtures in the open hallway. The result – blue-yellow and red-yellow color. The spies see them, but cannot determine what secret colors were used.

Alice takes Bob's mixture and adds her blue shade – she gets red-yellow-blue. Bob takes Alice's mixture and adds his red shade – he ends up with blue-yellow-red. Both resulting mixtures are identical. Alice and Bob now own a unique color that remained hidden.

In practice, it is not about colors, but rather about mathematical operations with public and private keys. The underlying mathematics makes it even stronger – it is practically impossible to guess the secret “colors” just from the knowledge of the resulting mixture.

How does secure message exchange work

Once the parties own a shared secret, they can use it for symmetric encryption. Real implementations add additional security layers that remain hidden from the user. After connecting to a friend in the E2EE app, all encryption and decryption occurs only on your devices – unless there are serious security threats at the software level.

Regardless of whether you are a hacker, a tech company, or a law enforcement agency – if the service is truly end-to-end encrypted, every intercepted message appears as a nonsensical string of characters.

End-to-End Encryption Limitations

The main criticism of E2EE comes from those who argue that without the proper key, no one has access to the messages – not even governments. Their argument is: if you are behaving according to the law, you should have no reason to hide your messages. This perspective is reflected in the attempts of some politicians to introduce legislation with “backdoors” for access to encrypted communication. However, such solutions would completely undermine the purpose of E2EE.

It is essential to realize that E2EE applications are not perfectly secure. Messages may remain masked during transmission, but they are visible in plaintext at the endpoints – on your laptop or mobile. This itself is not a flaw of E2EE, but a point worth remembering.

There are other threats that you need to be aware of:

• Device theft: without a PIN code or if the attacker bypasses it, they may gain access to your messages.
• Infected devices: malware can snoop for information before sending it and afterwards.
• Man-in-the-middle attack: during the key exchange, you cannot be sure that you are communicating with the right person. An attacker could impersonate your friend and intercept and modify your messages.

To minimize such threats, a security code helps – numerical strings or QR codes that you can verify through a secure channel ideally in person. When the numbers match, you can be sure that the third party is not you.

Why End-to-End Encryption is Valuable

Without the aforementioned threats, E2EE is undeniably a powerful tool for enhancing privacy and security. Privacy advocates promote it globally – similar to onion routing. Bonus: it can be integrated into applications that resemble those we are used to, making it accessible to anyone with a mobile device.

E2EE is not just for criminals and whistleblowers – that is a misconception. Even the largest tech corporations are not immune to attacks that expose unencrypted user data to malicious actors. Access to personal communications or identity documents can ruin lives.

If a company is attacked, but its users rely on E2EE, hackers will not gain access to the readable content of messages ( assuming robust encryption). At best, they will only access the metadata – which is still concerning, but represents a significant improvement.

Conclusion

Globally, the number of freely available E2EE tools is increasing. iOS comes with Apple iMessage, Android with Google Duo, and the list of other privacy-focused software continues to grow.

End-to-end encryption is not an all-powerful shield against all cyber attacks. However, if you actively use it, you can significantly reduce the online risks you are exposed to. Alongside the Tor network, VPNs, and cryptocurrencies, messengers with E2EE represent an important part of your digital privacy arsenal.