How to choose the right information protection method: a comparison of symmetric and asymmetric encryption of data

Why Cryptography is Divided into Two Approaches

In today's digital world, cryptographic systems operate on two fundamentally different schemes: single-ring and double-ring models. When it comes to the main areas of research, symmetric key cryptography and asymmetric key cryptography represent the two branches upon which all modern security systems rely.

In practice, this division looks like this:

• Single Key Model — the same key is used to both encrypt and decrypt information.
• Key Pair Model — two interrelated keys are used: one for encoding, the other for decoding.

Both approaches are widely used, but in different contexts. Understanding their differences is critically important for those working with data protection.

Key difference: one key vs two

The fundamental difference between these two methods lies in the number and purpose of the keys. In systems with a single key, both parties in the communication have the same cryptographic material. In contrast, systems with two keys assume that one key is public and can be distributed, while the other remains private and confidential.

This is not just a technical detail — it fundamentally changes the ways in which systems operate, the risks they are exposed to, and where they can be most effective.

How Cryptographic Keys Work

Keys in cryptography are sequences of bits generated by specific algorithms. Their length and nature determine the security of the entire system.

In systems with a single key, both operations—encoding and decoding—are performed using the same sequence of bits. This means that if Katya sends an encrypted message to Maxym, she must transmit the same key to him. If this key is intercepted by a malicious actor, they will gain access to all the information.

In contrast, in systems with two keys:

• Public key is used for encrypting data and can be widely distributed.
• Private key is used for decryption and is kept secret.

If Katya uses a dual-key model, she encrypts the message with Maxim's public key, and only he can decrypt it using his private key. Even if a third party intercepts the message and finds the public key, they will not be able to decode the information.

Key Length as an Indicator of Security

There is a significant difference in the length of cryptographic sequences between models. In single-key systems, keys usually have a length of 128 or 256 bits, depending on the required level of protection. This value is quite modest due to the absence of mathematical patterns that can be exploited.

The situation is different with dual-ring systems. Since there is a mathematical relationship between the public and private keys, an attacker could potentially attempt to find a pattern to crack the code. To mitigate this risk, asymmetric keys must be significantly longer—typically 2048 bits or more.

Comparing security levels: A 128-bit key of a single-use model provides approximately the same level of protection as a 2048-bit key of a dual-ring model.

Which method to choose: advantages and disadvantages

Each model has clear advantages and limitations:

Single Key Systems:

• ✓ Faster data processing
• ✓ Lower computational requirements
• ✗ The problem of distributing the key ( to everyone who needs access requires transferring one key ).
• ✗ Higher risk of compromise due to ease of interception

Two-Key Systems:

• ✓ Solves the problem of key distribution (the public key can be shared freely)
• ✓ Higher level of security for confidential communication
• ✗ Significantly slower processing
• ✗ Requires more computational resources

Where and How Data Encryption is Applied

Single-ring systems ( AES, DES ): Due to their speed, these methods are used for mass data protection. The American standard AES (, an extended encryption standard ), is used by the US government to protect classified information. The previously developed standard DES ( from the 1970s ) served as a predecessor to modern solutions.

Dual-circuit systems: Used in scenarios where security is more important than speed. Encrypted email is a classic example: a public key encrypts the message, and a private key decrypts it. RSA and ECDSA are the two main algorithms in this category.

Hybrid models (SSL/TLS): In practice, both methods often work together. SSL and TLS protocols combine the advantages of both approaches to ensure the security of internet communications. SSL is now considered outdated, but TLS remains the standard in all major browsers.

Data Encryption in the Cryptocurrency World

Encoding methods are widely used in cryptocurrency wallets to enhance security. When a user sets a password to access the wallet, the file is encrypted using these methods.

However, there is a common misconception: many think that Bitcoin and other cryptocurrencies use dual-ring encryption. In fact, this is not entirely true. Although pairs of public-private keys are indeed used in blockchain systems, it does not mean that encryption as such is being employed.

For example, the ECDSA algorithm used in Bitcoin is a digital signature algorithm, not encryption. Messages can be signed with a digital signature without any encoding of information. This is fundamentally different from RSA, which can work for both encryption and signing.

Conclusion: both methods have merit

Both single-key and double-key cryptographic systems remain an integral part of modern digital security. Each model has its niche: one is optimal for rapid mass data protection, while the other is for confidential communication and identification.

With the advancement of technology and the emergence of new threats, both approaches will continue to evolve, remaining key components of computer security and digital innovation across all sectors—from government systems to personal cryptocurrency wallets.