Symmetric Encryption

This is the simplest kind of encryption that involves in using one secret key. It is the oldest known encryption method and Caesar cipher falls in to this category. The secret key can be as simple as a number or a string of letters etc. For instance, let us look at a shift cipher which is a simple symmetric encryption technique that can be elegantly demonstrated. We have the plain text ‘I want to send a secret message’ in our hands, and our secret key is to shift each letter by three positions. So if you have ‘A’ in the plaintext, it will become ‘D’ in the cipher text. This is what is known as the Caesar cipher, and your cipher text would look like ‘L zdqw wr vhqg d vhfuhw phvvdjh’. At a glance, it’s incomprehensible, but once you decode it with the secret key, it becomes plain text again. There are a lot of symmetric key encryption algorithms in use today which includes stream ciphers like RC4, FISH, Py, QUAD, SNOW etc. and block ciphers like AES, Blowfish, DES, Serpent, Camellia etc.