ELI5: Explain Like I'm 5

Symmetric-key algorithm

A symmetric-key algorithm is a type of encryption used to keep information safe and secure. It works by taking some information (like a message) and transforming it into a jumbled form – like a code – that is unreadable unless you have the key to unlock it. The key is like a special password that only authorized people can use to decode the information. The same key is used to both encrypt and decrypt the data.