Understanding Encryption

Today we live surrounded by data. From our private messages to online shopping, digital information is everywhere. But how do we know that our information is safe? The answer lies in cryptography and encryption. In this article, I want to explain in simple terms how different encryption algorithms work, how they protect us, and especially what end-to-end encryption is. Additionally, we will explore a modern and efficient technique: Elliptic Curve Cryptography.

What is Cryptography?

Cryptography is the science and art of protecting information through the use of mathematical techniques and algorithms to ensure that only authorized people can access it. Its purpose is to guarantee the confidentiality, integrity, authenticity, and non-repudiation of data, meaning ensuring that information is not altered, comes from a legitimate source, and its transmission cannot be denied.

How Does It Work?

Cryptography turns readable data (plaintext) into an unreadable format (ciphertext) through a process called encryption. This process uses a key (which is a sequence of bits) and an algorithm (a set of mathematical rules) to make this change. To make the information readable again, the reverse process called decryption must be used, which also requires a key.

A Brief History of Cryptography

Encryption is like a digital lock that keeps our information safe. There are two key moments when this lock comes into play: when data is at rest and when it’s in motion. Let me break it down for you in a simple and practical way.

Encrypting data at rest

Imagine you keep your personal diary in a drawer. If someone breaks into your house, they can open the drawer and read it. Encryption for data at rest works like a lock for that drawer, but digitally. For example, on your phone or laptop, full-disk encryption locks the entire device with a password, fingerprint, or PIN. Without access, no one can read your files, even if they steal your device.

But remember, locking your phone doesn’t always mean it’s encrypted. That’s why it’s important to check that encryption is turned on. This way, if you leave your phone behind at a restaurant, your data will still be protected.

You can also encrypt specific files. If you have sensitive photos or documents, you can encrypt them individually, in addition to encrypting your entire device. It’s like putting a lock on the drawer but also keeping your diary in a safe within that drawer.

Encrypting data in transit

Now think about a message you send to a friend. That message travels from your phone to the app’s servers and then to your friend’s phone. This is where encryption for data in transit protects the information while it moves through the network.

There are two main types of transit encryption: transport layer encryption and end-to-end encryption.

Transport layer encryption acts like a tunnel between your device and the app’s servers. For example, when you use a website that starts with “https://,” you’re using this type of encryption. But be careful: while the tunnel protects data during its journey, the app’s servers can still read and store your message, like opening a letter at their post office.

End-to-end encryption is much safer. Here, only you and your friend can read the messages, as if you sent a locked letter that only the two of you have the key to. Apps like Signal or WhatsApp use this system, meaning not even the app company can see your messages.

End-to-end encryption is one of the most effective ways to protect data. This technique ensures that data is encrypted from the moment it is sent from a device until it is received on the recipient’s device. This means no one else can read the message, not even the service providers we are using.

In other words, end-to-end encryption acts like a lock that only the recipient can open with the correct key, while the message travels through the internet. Thus, the security of communication does not rely on trusting third parties but on the encryption keys.

What encryption doesn’t do

While encryption protects your information, it’s not perfect. For instance, if you send encrypted messages, your friend can still take screenshots or save the conversation. Additionally, encryption doesn’t hide metadata: who’s talking to whom, at what time, and from where. This matters because metadata can tell a story even without the content of the message.

That’s why it’s a good idea to use encryption for everything, even mundane stuff. This normalizes its use and avoids drawing attention only when you’re sending something sensitive.

Combining both types

The best approach is to use both encryption at rest and in transit. If you only encrypt data at rest, your messages will be safe on your device, but they could be intercepted during transmission. On the other hand, if you use end-to-end encryption but don’t protect your device, someone with physical access could read your messages.

For example, if you lose your phone and it’s not encrypted, anyone with access can read your chats, even if you used a secure app. Or, if you send an unencrypted message from a protected phone, someone could intercept it over the network.

That’s why encryption works best as a layered strategy. Protect what you store and what you send. It’s the best way to keep your information safe, no matter the threat.

Different Types of Encryption Algorithms

There are several types of encryption algorithms used to protect data. Below, I explain the most common ones and their advantages and disadvantages:

Symmetric Encryption: In this type of encryption, the same secret key is used to encrypt and decrypt the information. It’s like having a safe with only one key, which is used both to lock and unlock the safe.

Asymmetric Encryption: Unlike symmetric encryption, asymmetric encryption uses two different keys: a public key for encryption and a private key for decryption. It’s like having a safe with a public lock that anyone can put a message into, but only you, with your private key, can open it.

Elliptic Curve Cryptography: is a modern and highly efficient variant of asymmetric cryptography. Instead of relying on the factorization of large numbers (like RSA), ECC uses points on an elliptic curve to perform equivalent calculations but with much smaller keys. This offers the same level of security as algorithms like RSA but with less storage, processing power, and energy required. Why is it important? ECC is very useful in devices with limited resources, such as mobile phones or embedded systems. Due to its smaller keys, it can be implemented more efficiently without sacrificing security.

In Summary

Cryptography is essential to keeping our information secure in the digital age. Encryption algorithms like symmetric encryption, asymmetric encryption, and elliptic curve cryptography allow us to protect our data effectively. Each type of encryption has its advantages and disadvantages, so choosing the right algorithm depends on the security and efficiency needs of each situation.

Moreover, quantum computing poses a challenge for modern cryptography, but new algorithms are being developed to face this challenge and ensure our communications remain secure in the future.

End-to-end encryption is one of the best practices for protecting privacy in digital communications, ensuring that only legitimate recipients can access the information. As threats evolve, it’s crucial that we understand and adopt the most secure and effective encryption technologies.