Privacy protection in the digital world: understanding end-to-end encryption

Why are your messages available to everyone?

When you send a message through a mobile application, it may give the impression of complete privacy in communication. In reality, however, your message goes through many intermediary servers before reaching the recipient. The server sees the recipient, the content, the time of sending – all the information in full. Even if the company does not publish your conversations, the database containing millions of messages remains an attractive target for hackers.

Large-scale data breaches occur regularly. Without proper protection, your private information can fall into the hands of malicious actors with all the consequences that follow. This is why end-to-end encryption technology is becoming increasingly relevant.

What is end-to-end encryption: basics

End-to-end encryption (E2EE) is a method of cryptographic protection where only the sender and the recipient have access to the content of messages. No one else, including the intermediary server itself, can read the data. The history of this technology dates back to the 1990s when cryptographer Phil Zimmerman developed the Pretty Good Privacy program (PGP), which became the prototype for modern security systems.

The concept is simple to describe, but complex to implement. Information must be encrypted on the sender's device and decrypted only on the recipient's device. At all other stages of transmission – in the network, on servers – the data is an incomprehensible set of symbols.

How unencrypted message transmission works

A typical scheme works like this: you install the application, create an account, and are ready to communicate. You enter text, specify a contact, and send the message. It goes to the application's central server, which determines the recipient and forwards the data to them.

This is a “client-server” model. Your phone (client) performs basic functions, with the main work happening on a remote server. The server acts as an intermediary between you and the contact.

Encryption may be used between your device and the server (, such as the TLS protocol), and also between the server and the recipient. However, on the server itself, the message is stored in plaintext. It is protected from interception during transmission but is vulnerable at the storage location.

Such protection prevents man-in-the-middle attacks only at the moment of transmission. However, the server, having access to decrypted information, becomes a source of risk in case of hacking or data leakage.

Mechanism of Operation: From Key Exchange to Security

End-to-end encryption begins with the exchange of cryptographic keys between participants. One of the most reliable methods is the Diffie-Hellman protocol, developed by cryptographers Whitfield Diffie, Martin Hellman, and Ralph Merkle.

The revolutionary aspect of this approach is that the parties can create a shared secret key even in an open, potentially eavesdropped environment – without a physical exchange of keys. This is especially valuable in the internet age, when people communicate through uncontrolled channels.

Working principle: analogy with paints

Imagine two people in different hotel rooms, being observed. Alice and Bob want to obtain the same color of paint, known only to them.

First, they agree on a public color – for example, yellow. Everyone takes a can of yellow paint. Then, in their rooms, they add a secret color: Alice adds blue, Bob adds red. No one knows about these secret colors.

They come out with the received mixtures (blue-yellow and red-yellow) and exchange them right in the hallway. Observers see the exchange but cannot determine the exact shades of the added colors.

Then everyone returns to the room with someone else's mixture and adds their secret color again:

• Alice mixes her blue with Bob's red-yellow mixture → red-yellow-blue
• Bob mixes his red with Alice's blue-yellow mixture → blue-yellow-red

Both combinations yield the same final color. Alice and Bob obtained a unique secret that remains unknown to observers.

In reality, mathematical functions and open/closed cryptographic keys are used instead of paints. The complexity of the calculations makes brute-forcing the “secret color” practically impossible even for powerful computers.

Secure Message Exchange

After establishing a secure channel, all messages are encrypted and decrypted locally – only on your devices. Applications that use such technology (WhatsApp, Signal, and others) guarantee that the content is protected from end to end.

Any interceptor – hacker, communication operator, or even a law enforcement officer – will receive a set of meaningless bytes. Without the appropriate key, it is impossible to decode the information.

Advantages of End-to-End Encryption

When implemented correctly, E2EE provides a significant boost to privacy. Like onion routing (Tor), this is a technology promoted by privacy protection activists around the world.

Availability for Everyone. End-to-end encryption easily integrates into familiar applications. You don't need specialized knowledge – just have a smartphone.

Protection against hacks. Even if the company is hacked, the content of the protected messages will remain inaccessible. Hackers will only be able to obtain metadata (such as the time of sending, recipients), but not the essence of the correspondence.

Risk Reduction. Data leaks regarding identity documents or confidential negotiations can have catastrophic consequences. End-to-end encryption virtually eliminates such risks.

Limitations and Vulnerabilities

This technology has important limitations that are essential to understand.

Device as the Weak Link. The message is encrypted during transmission but is accessible at the endpoints – your laptop or smartphone. If the device is stolen or hacked, the protection becomes meaningless. Malware can capture information before it is sent and after it is received.

Initial stage attack. During the first key exchange, you cannot be completely sure of the authenticity of the other party. An attacker may impersonate your contact, intercept the keys, and gain access to all correspondence. Many applications use security codes – numerical sequences or QR codes that can be shared through a separate secure channel for verification.

Political pressure. Some government structures and politicians believe that E2EE complicates law enforcement activities and lobby for the creation of “backdoors” to access communications. This contradicts the very essence of the technology and meets resistance from the cryptographic community.

End-to-End Encryption in Modern Times

The number of freely available tools for implementing E2EE is growing. Apple iMessage and Google Duo are built into iOS and Android. More and more privacy-focused applications are emerging.

It is important to note: end-to-end encryption is not a universal solution against all cyberattacks. However, when used wisely, it significantly reduces risks. Together with VPNs, Tor, and other protection tools, end-to-end encryption becomes an essential part of the digital security arsenal.

If you take privacy seriously, you should actively use E2EE in messengers and, where possible, use other secure communication channels.