## Why You Need to Protect Your Messages: A Comprehensive Guide to End-to-End Encryption

### The problem we face in the world of digital communications

In the current era, most messaging applications rely on a model called "client-server." When you write a message and send it to a friend, the message does not go directly from your device to theirs. Instead, it is stored on centralized servers managed by the service provider, who then routes it to the recipient. It may seem like a reasonable system, but there are serious implications to this design.

The problem is not just in transmitting the message itself. There is a possibility that the server keeps a copy of every connection you make, stored in massive databases. Repeated incidents of security breaches prove that this data can fall into the wrong hands. This is where **end-to-end encryption** comes in as a fundamental solution.

What does encryption between endpoints mean?

End-to-end encryption ###E2EE( is a technology that ensures your messages remain readable only by the intended recipient and the original sender. No intermediary server, service provider, or even security forces can access your message's content. All communications – whether text messages, emails, files, or even video calls – are encrypted in a way that can only be decrypted with the correct key.

Applications like Signal, WhatsApp, and Google Duo use this technology. When a message is sent through them, the encryption and decryption occur exclusively on your device and the recipient's device.

Where did this idea come from? )

The roots of end-to-end encryption date back to the 1990s. At that time, Phil Zimmerman developed a program called "Pretty Good Privacy" ###PGP(, which is a well-known acronym in the encryption community. This was a turning point in the history of digital privacy, as it enabled ordinary individuals to encrypt their private communications.

) How does an unencrypted message work?

Before understanding the power of encryption between endpoints, we must understand the vulnerabilities of traditional systems.

When you use a regular messaging app, you install it and create an account. After that, you write a message and select the recipient from the contact list. The message is sent to the central server, which sees that you sent the message to a specific person and then forwards it to its destination.

Data may appear to be protected between your device and the server ###A ← → S( and between the server and the recipient )S ← → B(, and indeed most servers use the TLS )Transport Layer Security( protocol which provides encryption. However, this encryption only protects against external intruders attempting to intercept data during transmission. The server itself can easily read the message.

The critical point: If the data is encrypted with a key that only the recipient possesses before it reaches the server, then the server will never be able to read it. This is exactly what end-to-end encryption achieves.

Without this technology, the service provider can store millions of messages in a single database. When a security breach occurs, all of this sensitive data becomes exposed to risk.

) Technical mechanism: Key exchange

To implement encryption between endpoints, both parties must have a secure way to share a secret key. This is where **Diffie-Hellman Key Exchange** comes into play, a technique developed by cryptographers Whitfield Diffie, Martin Hellman, and Ralph Merkle.

The main idea is that both parties can produce a shared secret even in an insecure environment, where third parties may be monitoring the communication.

To clarify this, let's use an analogy: Imagine that Alice and Bob are in separate hotel rooms at either end of a corridor, and they want to share a secret paint color without the spies lurking in the corridor knowing.

First, they agree on a common color like yellow and buy a can of it and divide it. Each takes half to their room.

In his room, each mixes a secret color that no one knows – Alice chooses blue, and Bob chooses red. Now each has a mixture of ### yellow + blue ( and ) yellow + red (.

They exchange the mixtures openly in the hallway. It doesn't matter if the spies see them, because they won't know the exact shades that were added.

Upon returning to the room, each takes the other's mixture and adds their secret color:
- Don't you mix her blue with a mix of pop ) yellow + red ( → you get ) yellow + red + blue (
- Bob mixes his red with a mixture of Alice ) yellow + blue ( → gets ) yellow + blue + red (

The result: They have the same color! This shared secret could not be discovered by the spies. In actual mathematics, this is more complex, but the principle applies to digital keys and encryption.

) encrypted message exchange

Once both parties possess their shared secret, they use it as the basis for a symmetric encryption system. Modern applications add additional layers of security, but all of this occurs behind the scenes without the user noticing.

When you message a friend on an end-to-end encrypted app, encryption and decryption can only occur on your two devices. Even if someone intercepts the message while it is being transmitted, it will appear as random meaningless characters.

### the real benefits

In the absence of weaknesses, encryption between endpoints provides real benefits:

**Protection against data breaches**: Even if an attacker breaches the service provider's servers, they will find nothing but useless encrypted messages.

**Actual Privacy**: The service provider itself cannot access the content of your messages, meaning it cannot sell your messaging data or use it for targeted advertising.

**Accessibility**: Encryption is integrated across popular and user-friendly applications, making it accessible to everyone, not just encryption experts.

**Defense Against Mass Surveillance**: Contrary to what some believe, this technology is not just a tool for criminals. Companies facing the highest levels of security have proven to be vulnerable to attacks. Employees of companies, activists, journalists, and ordinary individuals who want to protect sensitive information – all benefit from this protection.

### challenges and flaws

However, encryption between endpoints is not a magic shield:

**Monitoring after decryption**: The message appears in plain text on your device before it is sent and after it is received. If your device is infected with malware, an attacker may be able to see your messages.

**Device Theft**: If someone steals your phone and it is not protected by a strong PIN code, they can access all your messages.

**Eavesdropping Attacks**: At the beginning of the connection, you may not be certain whether you are exchanging the key with your friend or with an attacker. If eavesdropping occurs, the attacker may read your messages and relay them to your friend without either of you knowing.

To verify your identity, most applications provide security numbers or QR codes that you can verify with your contacts through a secure channel outside the app.

**Political Opposition**: Some politicians oppose encryption between parties because it prevents authorities from accessing communications. However, this contradicts the essence of digital privacy.

### Comprehensive protection for your privacy

Encryption between endpoints is not the only solution, but it is a crucial part of a comprehensive digital security strategy. When combined with other technologies such as VPNs, the Tor application, and privacy-focused cryptocurrencies, you can build strong defenses against surveillance and breaches.

There is a growing number of free and open-source encryption tools between endpoints. Apple's iMessage and Google's Duo come with this technology enabled by default on iOS and Android systems. New privacy-focused software continues to emerge.

Summary: End-to-end encryption is not a fantasy or a complex tool available only to specialists. It is a practical and applicable technology now. With some effort and awareness, you can effectively use end-to-end encryption to significantly reduce the risks you face online and maintain your true digital privacy.