and decryption at both ends. The encryptor applies the key to the plain text data which results in a cipher text. The decryptor reverses the by applying the same key to the cipher text to reveal the plain text data. The most common symmetric encryption system is the Data Encryption Standard (DES), of which there are several variations.

Public Key Encryption systems are a lot more complex than symmetric encryption systems such as DES and depend upon mathematical functions that are often referred to as “trap-door” functions. They involve complex mathematical formulae which normally involve exponentiation to high powers, modular arithmetic and the products of large prime numbers.