Symmetric vs Asymmetric Encryption

What are the differences when comparing symmetric vs asymmetric encryption? Does one approach work better than the other, or do they work best when used together? In this definition, we define both types of encryption and answer these questions.

What Is Symmetric Encryption?

Encryption is a common method for increasing data security that works by rearranging data so only authorized users can make sense of it. Basic encryption involves the use of secret keys to “unlock” data. In symmetric encryption, only a single secret key is used between two or more users. 

Consider an email. The sender will use the secret key to encrypt an email message before it’s sent. Next, the recipient will use the same key to decrypt the message so it’s possible to read and comprehend the original message.

Symmetric encryption use cases

Symmetric encryption is a simple process, making it an ideal solution for processes that require fast encryption and decryption, such as banking transactions. It’s also frequently used when storing or accessing data via the cloud.

Pros of symmetric encryption

  • Speed: The symmetric encryption process is simple in nature. It does not require a large amount of computer or network resources to complete, making it a fast encryption option.
  • Capable of handling large datasets: Due to the speed and simplicity of symmetric encryption, it’s a great option for quickly encrypting and decrypting large datasets.

Cons of symmetric encryption

  • Key sharing is required: For symmetric encryption to work, the secret key must be shared. Unfortunately, sharing the key via email or another messaging tool increases the risk of a data breach. Keys should be shared in person, if possible, and stored somewhere physical.
  • Unauthorized access can result in severe consequences: While only using one key results in increased efficiency, it can also be a downside. When one key is securing large amounts of data (if not all data), a breach is likely to affect more sensitive business data.

What Is Asymmetric Encryption?

Asymmetric encryption is also known as public-key encryption. This is because both public and private keys are used to make it work. In asymmetric encryption, two or more keys are used to encrypt and decrypt data. Typically, one key is publicly accessible by all users and one is privately accessible by the intended recipient.

Consider another email. To encrypt an email, the sender would use the publicly accessible key. The recipient would then use a private key to decrypt the message.

Asymmetric encryption use cases

One of the most common use cases for asymmetric encryption is verifying digital signatures. A digital signature is used to prove the identity of a sender in financial transactions, remote contract signing, and more. To prove the sender’s identity, a private key is attached to a message and a public key is then used to verify that the private key belongs to the sender.

Just like symmetric encryption, asymmetric encryption can also be used for more common tasks such as basic email and web security.

Pros of asymmetric encryption

  • Enhanced security: Asymmetric doesn’t rely on one key for encryption. Instead, two keys are required to complete the process. This added complexity makes asymmetric encryption inherently more secure.
  • No key exchange required: Asymmetric encryption does not require a key exchange. Private keys are kept private and public keys are available at all times. This also enhances the security of encryption because keys don’t need to be shared between sender and recipient.

Cons of asymmetric encryption

  • Slower speeds: Asymmetric encryption requires longer key lengths. Plus, networks must process two different keys instead of one. This results in a slower encryption process when asymmetric encryption is used. Asymmetric encryption is not suitable for large datasets.

Symmetric vs Asymmetric Encryption: Key Differences

Both encryption methods can be valuable for a variety of different use cases. However, to determine which method is best, it’s important to understand the key differences between symmetric encryption and asymmetric encryption:

Secret keys

The main difference lies in how encryption is completed. In symmetric encryption, only one private secret key is used. In asymmetric encryption, two secret keys, one public and one private, are involved.

Speed

Because it only requires one key, symmetric encryption is faster to complete than asymmetric encryption. Asymmetric encryption also uses longer keys (from 2,048 to 4,096 bits) which take longer to process.

Security

Asymmetric encryption is often considered more secure than symmetric encryption simply because a secret key doesn’t need to be exchanged.

Data size

Symmetric encryption is better suited for large amounts of data due to its simplicity. In contrast, asymmetric encryption is better suited for smaller amounts of data.

Should You Use Symmetric and Asymmetric Encryption Together?

Symmetric and asymmetric encryption come together in a method known as hybrid encryption. Using the hybrid method, a symmetric key is generated when a message is encrypted. The public key is then used to encrypt the symmetric key instead of the entire message. Although it won’t fit every business use case, this approach combines many of the best features of symmetric and asymmetric encryption.

Read next: Best Encryption Software

Brenna Miles
Brenna Miles
Brenna Miles is a contributing writer for Webopedia and TechRepublic.com, where she covers CRM, PLM, security, and IT automation. Since 2013, she's written everything from blog posts to industry white papers about everything from SaaS to network security and back again.

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