Asymmetric and Symmetric key cryptography: A Comparison

  • Number of keys

Symmetric encryption utilizes a single key for encryption and the same key for decryption.
Asymmetric encryption utilizes two keys – one key (public) for encryption and another key (private) for decryption.
Symmetric encryption has the advantage here for simplicity, speed, and requirement of fewer resources.

  • Digital signatures

Data sent through asymmetric key encryption allows for the use of digital signatures and message authentication. Symmetric key encryption does not.
Asymmetric key encryption has an advantage here as it ensures an added Integrity factor, along with the Confidentiality of symmetric key encryption. It also brings in the added benefit of non-repudiation.

  • Impact of compromised keys

When a symmetric key is compromised, the contents of only that particular message, that it was used to encrypt, is compromised. All other messages remain encrypted, as each message gets encrypted by a different key.

When the private key of an asymmetric encryption is compromised all the messages that are received by that recipient are compromised.

The advantage here is with symmetric key encryption as the damage caused by a compromised symmetric key is lesser than the damage caused by the compromise of the private key of an asymmetric encryption.