The two primary types of encryption used today are known as Symmetric Encryption and Asymmetric Encryption. But before diving into these, let’s go over a valuable term: cryptographic keys.
Cryptographic keys are the codes or strings of data used to encrypt and decrypt data. As the second half of the term implies, these codes serve as keys to lock and unlock cryptographic functions.
Symmetric Encryption: A Shared Secret
When sending personal letters, Julius Caesar used a method that is today known as Caesar Cipher or Caesar’s Code. It was one of the earliest, most simplified methods of encryption, whereby the technique was to substitute alphanumeric characters by shifting each character a certain number down the alphabet. To send the encryption for “WAVE BL,” we would send “JNIR OY.” If the message receiver knows our key, they will also know how to decrypt the message, rotating 13 characters backward in the alphabet, returning to the original “WAVE BL.”
In symmetric encryption, the same key is applied to encrypt the plaintext (the unencrypted information) and decrypt the ciphertext (the unreadable output). In other words, the knowledge of what is shared is identical on both sides.