What is end-to-end encryption? How does it work?

Online privacy is the need of the hour. Especially when there is a constant increase in the number of techniques used to steal user data. Recognizing this need, major online messaging services use a technique called end-to-end encryption, to secure and protect user conversations.

But what does end-to-end encryption mean and how does it actually work? Find out in this article!

Learn the basics of coding

Encryption means converting information into code, hiding the true meaning of the information.
Decryption means converting this code back to the original information and returning its meaning. It is the reverse mechanism of encryption.

Why do you need encryption?

When you send something online, be it a message, a comment, or an image – it carries some “information”. What we need to understand is that the message or image itself has no value – but it has value for the information it provides. It has value because of the information that people can interpret when they see it. So what happens if the message or image you are sending is also seen by a third party over the internet? They will know what information you are trying to convey. So what about encryption and decryption? This is where end-to-end encryption comes into play.

What is end-to-end encryption?

You encrypt the message/image you want to send and it travels over the Internet as a 'secret' code. Only the recipient can then decode this 'secret' code. This process is called end-to-end encryption.

In its simplest terms, end-to-end encryption ensures that communication between sender and receiver is confidential, preventing third parties from accessing this information. The tools and technologies that make this possible are built into messaging apps and other software that users (may) use.

How does end-to-end encryption work?

The goal of end-to-end encryption is to prevent any intruder from stealing information between the sender and the recipient. Let's go back to the scenario we discussed earlier: You're sending someone a message.

When you use an end-to-end encryption service, you are provided with a pair of public and private keys. These keys help you encrypt and decrypt. Along with that, the messaging app has an algorithm, which consists of mathematical functions that are used to encrypt or decrypt data.

When you send a message to someone, you are given a public key that maps to that person's chat box. The public key is used to encrypt the message, using an algorithm built into the messaging app. This public key helps you identify the recipient's device and the fact that the person is receiving the message.

Now, the recipient will use the private key, which helps decrypt the message and interpret the information in the message you sent. This private key is only available and specific to the recipient's device. Therefore, no one else can decrypt the message - at this point, end-to-end encryption has been successful.

This is the basic principle of how end-to-end encryption works. However, not all services use end-to-end encryption. Some tools often use transport layer encryption techniques instead. So what is the difference between these two techniques?

How is end-to-end encryption different from other types of encryption?

What makes end-to-end encryption unique compared to other encryption systems is that only the endpoints — the sender and the receiver — have the ability to decrypt and read the message. Symmetric key encryption, also known as single-key or secret-key encryption, also provides a continuous layer of encryption from sender to recipient, but it uses only one key to encrypt the message.

The key used in single-key encryption can be a password, code, or randomly generated string of numbers that is sent to the recipient of a message, allowing them to decrypt the message. It can be complex and make the message appear like gibberish to intermediaries. However, the message can be intercepted, decrypted, and read, regardless of how drastically the key is altered, if an intermediary has the key. End-to-end encryption, with two keys, can prevent an intermediary from accessing the key and decrypting the message.

Another standard encryption strategy is encryption in transit. In this strategy, the message is encrypted by the sender, intentionally decrypted at an intermediate point -- a third-party server owned by the messaging service provider -- and then re-encrypted and sent to the recipient. The message is unreadable in transit and can use two-key encryption, but it does not use end-to-end encryption because the message is decrypted before it reaches the final recipient.

Encryption in transit, like end-to-end encryption, prevents messages from being intercepted along their journey, but it creates potential vulnerabilities at the point in between where they are decrypted. The Transport Layer Security encryption protocol is an example of encryption in transit.

How are end-to-end encryption and transport layer encryption different?

As mentioned earlier, not all services are end-to-end encrypted. But, that doesn’t mean they don’t have any encryption at all. The most common form of encryption for websites is TLS encryption – Transport Layer Security.

The only difference between this type of encryption and end-to-end encryption is that in TLS, the encryption takes place on the sender’s device and is decrypted at the server. So it is not truly end-to-end encryption but it provides a good level of security and is capable of protecting user information.

This is also known as encryption in transit. This means that the service provider can access all your messages through their servers. This is why you can easily view your old Instagram messages when you reload the app, but not on WhatsApp . You can only restore the messages by downloading the backup file and decrypting it on your device.

How is end-to-end encryption used?

End-to-end encryption is used where data security is needed, including in the financial, healthcare, and communications industries. It is often used to help companies comply with privacy and data security laws and regulations.

For example, an electronic POS system provider would include E2EE in its product to protect sensitive information, such as customer credit card data. Including E2EE would also help retailers comply with the Payment Card Industry Data Security Standard (PCI DSS), which requires that card numbers, magnetic stripe data, and security codes not be stored on client devices.

What does end-to-end encryption protect against?

E2EE protects against the following two threats:

• Prying Eyes . E2EE prevents anyone other than the sender and intended recipient from reading the message information during transmission because only the sender and recipient have the keys to decrypt the message. Although the message may be visible to the intermediate server helping to transfer the message, it will not be readable.
• Tampering . E2EE also protects against tampering with encrypted messages. There is no predictable way to alter an encrypted message in this way, so any attempt to alter it is pointless.

What does end-to-end encryption not protect?

Although E2EE key exchange is believed to be unbreakable using known algorithms and current computing power, there are several potential weaknesses that have been identified in the encryption scheme, including the following three:

• Metadata . While E2EE protects the information inside the message, it does not hide information about the message, such as the date and time it was sent or the participants in the exchange. This metadata can make it possible for bad actors interested in clues about the encrypted information to intercept the information after it has been unencrypted.
• Compromised endpoints. If either endpoint is compromised, the attacker can view messages before they are encrypted or after they are decrypted. Attackers can also obtain keys from the compromised endpoints and perform man-in-the-middle attacks using the stolen public key.
• Intermediaries are vulnerable . Sometimes providers claim to provide end-to-end encryption when what they actually provide is closer to encryption in transit. Data may be stored on an intermediary server where it could be accessed by unauthorized parties.

Advantages and disadvantages of end-to-end encryption

Here are some advantages of end-to-end encryption.

• Every step is fully protected.
• The messaging service server is unable to access messages and related information.
• Information cannot be accessed by unauthorized people online.
• You can't restore messages through a new login - unless you have an encrypted backup. Consider the Instagram and WhatsApp Messenger examples explained above.

Some disadvantages of end-to-end encryption include:

• Metadata such as date, time, and participant names are not encrypted.
• If the endpoints (sender or receiver) are vulnerable, then end-to-end encryption is of little use.
• In some cases, a Man-in-the-Middle attack can occur despite end-to-end encryption. Therefore, if someone chooses to physically impersonate the sender or recipient, messages and information can be read by unauthorized people.

Those are all the pros and cons of end-to-end encryption. If you’re still wondering whether you should turn on end-to-end encryption even if you’re not sending confidential messages, the answer is yes. Why give someone else access to your data?

Some popular end-to-end encrypted messaging apps

Here are some of the best end-to-end encrypted messaging apps for iPhone and Android. You can use any of these to add an extra layer of security to your messages.

1. WhatsApp Messaging Tool

The popular WhatsApp messaging app supports end-to-end encryption. You can use the links below to download and install it for both iPhone and Android.

2. Signal Private Messaging Tool

Signal is another feature-rich, end-to-end encrypted messaging app for iPhone and Android. It offers a more modern-looking user interface than WhatsApp.

Download Signal for iPhone Download Signal for Android

3. iMessage

iMessage, as we all know, is the basic messaging app for all Apple users. All messages and files on iMessage are end-to-end encrypted. However, it is not cross-platform and hence, not available for Android.

4. Telegram

Telegram is another feature-rich messaging app that we all want to use as our primary messaging app and wish all WhatsApp users would switch to. It offers end-to-end encryption, albeit on an optional basis. This option is called “secret chats”.

Those are all the popular apps that the article can recommend for encrypted private messaging.

That's all you need to know about end-to-end encryption. Hope you found this article helpful!