Symmetric vs Asymmetric Encryption: Key Differences

Learn how symmetric and asymmetric encryption work, compare their strengths, and see which one fits your security needs in 2025.

Encryption explained

Encryption is one of the most important concepts in the world of cybersecurity. It lays the foundation for secure communication between two systems, and ensures that the content cannot be read by unwanted parties.

Think of encryption as locking your diary with a key before leaving it on a park bench. Anyone can see the diary, but only those with the correct key can read what’s inside. Encryption protects messages, files, and even entire hard drives from prying eyes - whether those eyes belong to cyber-criminals, nosy co-workers, or rogue Wi-Fi hotspots.

There are two main ways to “lock” information:

  • Symmetric encryption — one shared key does all the locking and unlocking.
  • Asymmetric encryption — a key pair (public + private) splits those jobs so that locking and unlocking are handled by different keys.

In this article, you will find out what the difference is between the two cryptographic schemes.

What is symmetric encryption?

Symmetric encryption is the type of cryptography that you are most likely used to. The way it works is that you have a shared (symmetric) key which works just like a password. You use the same key for both the encryption and decryption of data, meaning that this password is identical when securing(encrypting) or retrieving(decrypting) data. Popular symemtric algorithms include AES-256, Blowfish and others.

Example: Say you have a file that you want to leave somewhere out in public (e.g.: a shared folder) but you only want people who know the password to be able to read the file. In that case, you secure the file (encrypt it) using symmetric key encryption.

What is asymmetric encryption?

The main difference between symmetric and asymmetric encryption is that asymmetric encryption uses 2 keys instead of 1. “Why would it use 2 keys?” you might ask. Well, with symmetric key encryption, that password that you use can be both an advantage and a disadvantage, because while it is easy to share with others and to use, it undermines the security of the encryption scheme.

Asymmetric encryption, on the other hand, uses two keys, one used for encrypting the data (the public key) and one used for decrypting the data (the private key). As the names suggest, the public key is meant for the public, while the private key is meant for your eyes only. Don’t share it anywhere! Some asymmetric algorithms are: RSA, ED25519 and others. These algorithms are also in the creation of SSH keys. Learn more about SSH Tunnels. Example: Someone can use your public key to encrypt a file, and only the one who holds the private key can then decrypt it.

This is the end of the article. I hope you enjoyed it and learned something new.