How encryption algorithms protect your data: from theory to practice

In the world of digital technology, information protection is becoming increasingly critical. Every time you send a message, make a purchase online, or log into a cryptocurrency wallet, your data goes through encryption. But do you know how these encryption algorithms actually work? Let's consider two main approaches that ensure security in the modern digital world.

Two paths of cryptography: symmetric and asymmetric

Cryptography is divided into two fundamental branches: symmetric key cryptography and public key cryptography. The first category encompasses symmetric encryption, while the second includes both asymmetric encryption and digital signatures. Such classification reflects different needs for information protection.

The main difference lies in the way keys are managed. While symmetric encryption uses a single key for both encoding and decoding data, asymmetric encryption works with two interrelated keys. This is not just a technical detail—it's a fundamentally different approach to protecting information.

What are cryptographic keys and how do they work

At the simplest level, a key encryption is a set of bits that mathematically transforms information. However, the ways to use these keys differ radically.

In symmetric encryption algorithms, the same key performs both functions: the person encrypting the data and the person decrypting it have the same key. Think of it as a physical lock: if two people have the same keys to one lock, they can both open it.

Asymmetric encryption changes this logic. Here, there is a public key ( that can be distributed ) and a private key ( that must be kept secret ). If Katya wants to send Maksym a secure message, she encrypts it with Maksym's public key. Only Maksym can decrypt the message using his private key. Even if a malicious actor intercepts the message and finds the public key, they will not be able to read it—this requires the private key.

Key Length: Why 128 bits is not enough for both types

The size of the key directly affects cryptographic strength. In symmetric encryption, keys typically have a length of 128 or 256 bits. This length is sufficient as there is no mathematical relationship between the public and private keys in symmetric systems.

In asymmetric encryption, the situation is different. The public and private keys are mathematically related, which theoretically allows an attacker to attempt to guess the private key based on the public one. To prevent such a breach, asymmetric keys must be much longer. Approximately equivalent levels of security are provided by a 128-bit symmetric key and a 2048-bit asymmetric key. That is why asymmetric systems require higher computational power.

Advantages and Disadvantages: Choosing a Tool for the Task

Symmetric encryption clearly wins in speed. Symmetric encryption algorithms require fewer computational resources, making them ideal for protecting large amounts of data. However, a critical problem arises here: how to share the key? If the key needs to be given to everyone who requires access to the data, the risk of interception increases.

Asymmetric encryption solves the problem of key distribution—public keys can be given to everyone without fear of compromise. But precio—it's slower operation. Due to the longer key lengths and more complex computations, asymmetric systems require significantly more resources, so they are not suitable for protecting large streams of data in real time.

Where are these encryption algorithms applied in practice

Symmetric encryption in action

The Advanced Encryption Standard (AES) is used by the US government to protect classified and confidential information. Previously, this role was performed by DES (Data Encryption Standard), developed in the 1970s, but it became obsolete due to insufficient key length. AES became its successor and remains the industry standard for symmetric encryption.

Asymmetric encryption in communications

Email with encryption is a classic example of using asymmetric encryption. Anyone can encrypt messages knowing the recipient's public key, but only the owner of the private key can decrypt it.

Hybrid Systems: The Best of Both Worlds

In practice, combined approaches are often used. The SSL (Secure Sockets Layer) and TLS (Transport Layer Security) protocols were designed for secure data transmission over the Internet specifically using a hybrid scheme. SSL is already considered obsolete and is no longer supported, while TLS remains a reliable standard integrated into all major browsers and web servers.

Cryptography in the World of Cryptocurrencies: A Common Mistake

In blockchain systems, including Bitcoin, pairs of public and private keys are widely used. However, this does not mean that asymmetric encryption is applied there. It is important to distinguish between two ways of using public keys: encryption and digital signatures.

A digital signature can be created without direct encryption. RSA is one of the algorithms that supports both methods. However, Bitcoin uses ECDSA (Elliptic Curve Digital Signature Algorithm), which serves for digital signatures without the application of encryption. Your public key is open, but your private key is needed not for decryption, but for signing transactions.

Regarding the protection of the wallets themselves: when a user sets a password for the wallet, the configuration file is encrypted using symmetric encryption algorithms. This provides an additional layer of data security at the local level.

Conclusion: both methods remain necessary

Symmetric and asymmetric encryption serve different purposes. Symmetric is fast, efficient, and often used internally within systems. Asymmetric is more secure for key distribution but slower. Instead, their combination in hybrid systems creates an optimal balance between security and performance.

As cryptography evolves as a science, both classes of encryption algorithms will continue to be actively used to protect against new, increasingly complex threats. Understanding how they work helps to gain a deeper awareness of why and how your data is protected in the modern digital world.