The security of information on the web is now an important topic. Data is often encrypted before being sent from one source to another, and many companies even encrypt information before storing it.

Encrypting data and information is necessary to prevent hackers and data snooping criminals from gaining access to sensitive information, such as an individual's personal details or credit card information.

So, we discuss two different types of encryption, symmetric and asymmetric, including the differences between the two.

What Is Symmetric Encryption?

An old encryption machine much like the Enigma

At its simplest, encryption simply means to use a key to encrypt data. This key is then required to decrypt the information as well. If the recipient doesn't have the key, they can't decrypt the data once it arrives at its destination. If you're new to the world of data encryption, you should also check out these basic encryption terms to gain a better understanding.

For instance, if you encrypt an email and send it to a person, they should also receive the encryption key, otherwise they simply can't view the contents of the email. Symmetric encryption is the simplest form of encryption, since it requires a single key to encrypt or decrypt information.

As you can probably guess, symmetric equation is a relatively old form of encryption, utilizing a secret key that can be an alphanumeric string, a number, or a word. It's also quite effective, and can even be used for full-disk encryption.

  • AES-128
  • AES-192
  • AES-256
  • RC4
  • DES
  • RC6

Why Use Symmetric Encryption?

The reason why symmetric encryption is popular is that it's relatively simple. This makes it easy and quicker to execute. Generally, symmetric encryption is used for encrypting larger amounts of data.

In most cases, the typical length of a symmetric encryption key is either 128 or 256 bits. Since only a single key is used, it doesn't require lots of resources to encrypt the information either.

The Problem with Symmetric Encryption

All parties must share the encryption key to allow for data transfer, exposing symmetric encryption to key exhaustion problems. If effective rotation isn't maintained, there's a risk that the key might be leaked.

There is also a risk that a hacker may receive bits of information that they can use to construct the encryption key themselves. This causes issues with scaling since you can't share the key with others.

What Is Asymmetric Encryption?

image of a padlock

Instead of relying on a single shared key, asymmetric encryption uses a couple of related keys. This includes a public and a private key, which automatically makes it more secure than symmetric encryption.

The public key is available to all parties, and is used for decrypting the plain text message before it is sent. But, in order to decrypt the actual message and read it, the parties must have access to the private key.

While there's a mathematical relationship between the public and the private key, hackers can't derive the private key using the information from the public key.

For instance, you can make available a public key to anyone who wishes to send you a message. But, the second key is kept secret, so only you know that one. Thus, when a message is encrypted and sent using the public key, a private key must also be required to decrypt it fully.

It's important to understand that the private key is only known to the person who owns it. Even the sender doesn't know the private key and can't decrypt the file once it is sent. Every authorized party in this exchange has their own private key that they can use to decrypt information.

The most common types of asymmetric encryption include:

  • RSA
  • SSL/TSL protocol
  • ECC
  • DSS

Why Is Asymmetric Encryption Considered More Secure?

Asymmetric encryption can be carried out automatically or manually, depending on the key's length. It's important to understand that the security of either lies primarily on the size of the key.

However, a significant reason why asymmetric encryption is considered more secure and reliable is because it doesn't involve the exchange of public keys between multiple parties. Even if a hacker gains access to a public key, there's no risk of them using it for decrypting the data (since the public key is used for encryption only), as they don't know the private keys.

More importantly, asymmetric encryption also supports digital signature algorithms and authentication, unlike symmetric encryption. This allows users to digitally sign documents or messages using their private keys, and others can use the corresponding public keys to confirm that the signatures are authentic and came from the verified sender.

The Problem with Asymmetric Encryption

Since it's obviously the more secure choice, why isn't asymmetric encryption the only standard in the world of encryption today? That's because when compared with symmetric encryption, it's considerably slower.

This has to do with the longer key lengths, and more importantly, the mathematical calculations involved in asymmetric encryption are considerably more complex, which means they require more CPU resources for decryption.

Even though there's a link between the public and private keys, asymmetric encryption relies primarily on longer key lengths to beef up security. It's essentially a compromise between speed and security.

For instance, as mentioned above, symmetric encryption relies on 128 or 256-bit keys. In comparison, the RSA encryption key size is generally 2048 bits or higher. And, with quantum computers seemingly becoming a reality very soon, even that might not be enough to protect information.

Symmetric vs. Asymmetric Encryption: Both Are Vital

Now that you understand the key concepts and differences between symmetric and asymmetric encryption, it's also important to highlight that both play a vital role in securing data.

Symmetric encryption is used for encrypting and moving relatively low-impact information that doesn't require heightened security. However, as the world looks towards post-quantum cryptography, even established encryption algorithms are no longer secure.

For instance, RSA, which is used in asymmetric encryption, isn't considered post-quantum secure anymore. As a result, encryption standards are constantly evolving, primarily as data security becomes more valuable.