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Asymmetric Encryption
Asymmetric encryption (sometimes called public key encryption) is a form of encryption where a pair of keys are responsible for encrypting and decrypting data.
This is different to symmetric encryption where the same key is used to encrypt and decrypt.
Our Symmetric Encryption page explains all about symmetric encryption.
Asymmetric encryption uses a special pairing of keys:
Public key
- Provided by the recipient
- It can be given to anyone who wishes to send encrypted data to the recipient
- Safe to share as all it can do is encrypt data
Private key
- Remains private on the computer, never sent or shared
- Only this key can decrypt the data encrypted using the public key
SSL uses a combination of symmetric and asymmetric encryption:
Asymmetric encryption is used to encrypt a symmetric encryption key, thus resolving the key distribution problem.
It is better to ultimately transmit data using symmetric encryption because it is faster.
Example process:
- A symmetric key is encrypted by the sending computer using the public key sent by the receiving computer (usually via SSL certificate)
- The encrypted symmetric key is sent to the receiving computer (unreadable if intercepted)
- Using the stored private key, the receiving computer decrypts the symmetric key
- Now, both computers have the same symmetric key ready for secure encrypted data transmission
