What is the difference between Symmetric and Asymmetric Encryption? Which is better for data security?

Companies in every sector must comply with standards and regulations, and one of the best ways to do this is to utilize encryption. Encryption takes data that can be clearly read, also known as plaintext, and runs it through an encryption algorithm. An encryption algorithm uses a key and mathematics to convert the plaintext into ciphertext, which is an undecipherable collection of letters and symbols. The process of encryption can be reversed using the same key, or the other key in a key pair, in a process called decryption. There are two different types of encryption: asymmetric and symmetric encryption.

Asymmetric vs Symmetric Encryption

Symmetric encryption involves the use of one key for both encryption and decryption. The plaintext is read into an encryption algorithm along with a key. The key works with the algorithm to turn the plaintext into ciphertext, thus encrypting the original sensitive data. This works well for data that is being stored and needs to be decrypted at a later date. The use of just one key for both encryption and decryption reveals an issue, as the compromise of the key would lead to a compromise of any data the key has encrypted. This also does not work for data-in-motion, which is where asymmetric encryption comes in.

Asymmetric encryption works with a pair of keys. The beginning of asymmetric encryption involves the creation of a pair of keys, one of which is a public key, and the other which is a private key. The public key is accessible by anyone, while the private key must be kept a secret from everyone but the creator of the key. This is because encryption occurs with the public key, while decryption occurs with the private key. The recipient of the sensitive data will provide the sender with their public key, which will be used to encrypt the data. This ensures that only the recipient can decrypt the data, with their own private key.

Uses for Asymmetric and Symmetric Encryption

Asymmetric and symmetric encryption are each better used for different situations. Symmetric encryption, with its use of a single key, is better used for data-at-rest. Data stored in databases needs to be encrypted to ensure it is not compromised or stolen. This data does not require two keys, just the one provided by symmetric encryption, as it only needs to be safe until it needs to be accessed in the future. Asymmetric encryption, on the other hand, should be used on data sent in emails to other people. If only symmetric encryption were used on data in emails, the attacker could take the key used for encryption and decryption and steal or compromise the data. With asymmetric encryption, the sender and recipient ensure only the recipient of the data can decrypt the data, because their public key was used to encrypt the data. Both types of encryption are used with other processes, like digital signing or compression, to provide even more security to the data.

Common Asymmetric and Symmetric Encryption Algorithms

Symmetric Encryption Algorithms: Asymmetric Encryption Algorithms:

Comparison Table

Asymmetric Encryption Symmetric Encryption
Definition A two-way function that takes in plaintext data, and turns it into undecipherable ciphertext. This process utilizes a public key for encryption and a private key for decryption. A two-way function that takes in plaintext data, and turns it into undecipherable ciphertext. This process uses the same key for both encryption and decryption.
Use Cases
  • Digital Signing: Asymmetric encryption is much better for digital signing, compared to symmetric encryption. The use of both a public and private key means the identity of the signer of the data can easily be known. The signer uses their private key for encryption, while the recipient verifies their identity with their public key. As only the public key of the signer can decrypt data encrypted with the signer’s private key, the identity of the signer is verified when the data is decrypted.
  • Blockchain: Again, the identification of the user during cryptocurrency transactions is much easier done with asymmetric encryption.
  • Public Key Infrastructure (PKI): The identity of key owners is proven with certificates in PKI, and thus asymmetric encryption is the better choice in PKIs.
  • Banking: Encrypting sensitive customer data in banks is extremely important, as is decrypting that information as quickly as possible. For this reason, symmetric encryption is the preferred method of encryption in banks, as one key encryption is much swifter than two key encryption.
  • Data Storage: As with banking, data storage services and products tend to use symmetric encryption. This method is much swifter to encrypt and decrypt data needed in a timely manner.
Advantages
  • The loss of the public key does not result in the compromise of data
  • More secure than symmetric encryption
  • Only the owner of the private key can decrypt the data sent to them
  • Simpler to implement
  • Faster than asymmetric encryption
  • Protects data from compromise
Disadvantages
  • Slower than symmetric encryption
  • More complicated to implement than symmetric encryption
  • Loss of a key means any data encrypted with that key can be compromised
  • Less secure than asymmetric encryption
Common Algorithms ECDSA, RSA, PGP AES, Blowfish, Twofish, RC4