Symmetric Encryption
Computer Science: OCR A Level, topic 3.1.5
Symmetric and Asymmetric Encryption
The use of encryption is vital to protect our private information. One type of encryption is symmetric encryption.
Symmetric encryption
- Symmetric or private key encryption is used to encrypt data for transmission.
- A private key is used to convert plain text into cypher text.
- This cypher text and private key are then transferred to another location or person.
- The key is then used to decrypt the cypher back into plain text.
Security
- Using a single key to encrypt and decrypt text proposes a massive flaw in security, as anyone with the key can decrypt the cypher.
- As with passwords, the longer the encryption key, the less likely it is to be compromised by brute force, and so the more secure the encryption.
Asymmetric encryption
- Asymmetric or public key encryption is a much stronger form of encryption and uses two keys: a public and a private key.
- The public key is given to anyone who wishes to send you encrypted data.
- This public key can only be used to encrypt information and not decrypt the information.
- The private key is used to decrypt the data, and only you have this key.
Public and private keys
- The public and private key are related to one another through mathematical operations.
- The private key you set cannot be figured out from the public key.
Test yourself on Symmetric Encryption
Symmetric Encryption
Is the following statement true or false?
Anyone with the private key can decrypt the cypher text generated by symmetric encryption.