Symmetric key encryption
aka single key encryption aka conventional encryption.
There are five ingredients in symmetric key encryption:
- Plain text – The input. It could be data or text.
- Encryption algorithm – The algorithm that transforms the plain text into gibberish. It performs substitutions and transformations on the plan text.
- Secret key – The secret key is also part of the input into the encryption algorithm. The substitutions and transformations generates different output depending on the key.
- Cipher text -This is the result of the plan text when the encryption algorithm is done with it.
- Decryption algorithm – This is kind of the encryption algorithm run backwards with the key, which “transforms” the cipher text into plain text.
There are two requirements for an symmetric key encryption algorithm:
- One should not be able to decipher the cipher text or extract the key even if it’s in possession of other cipher text along with the plain text that produced it.
- Sender and receiver has to make sure the key is stored and transferred securely. If the attacker knows the key and encryption algorithm it is able to decipher the text.