What is Encryption?
Encryption is the process of converting or transforming information. Its purpose, to hide that information from prying eyes. It is mathematically based, often involving a series of complex calculations. There are several different types of encryption, and they are used for various things. Common examples include securing personal information stored on social media websites like Facebook, hiding the login credentials for your personal computer, and protecting the password for your cell phone. Whatever the use, encryption works behind the scenes to protect your valuable information.
What is an Encryption Key?
An encryption key is a piece of external information used in the conversion process. Specifically, it provides an element of uniqueness to the process. For example, let say that you wanted to encrypt the message, ‘I like dogs’, using the key, ‘hello’. Then the resulting encrypted message might look like, ‘KJSUTSQKJIN’. Now, if we introduce another key, say ‘sunny’, and encrypt the same message, we might get something like ‘BMSNMFIENDU’. Same message, with different key, gives a different result. This is a powerful idea because it means that you can introduce a new level of randomness in the output of the encryption, simply by changing the key.
What Are the Various Types of Encryption Keys?
There are a number of key types out there. In fact, it seems like every article you read touts a new one. The reality, however, is that most are just variations of four basic types. They are symmetric, asymmetric, public, and private.
A symmetric key is one where encryption and decryption of a message is done with the same key. Often called shared secret encryption, both parties (sender and receiver) must have access to the key. The Data Encryption Standard (DES), and the Advanced Encryption Standard (AES), are examples of encryption methods that use this type of key. Asymmetric is the opposite. In this scenario, encryption is performed with one key, and decryption is performed with another. Public key encryption methods use this idea. Everyone uses a commonly known key for encryption, and each uses a unique key for decryption. RSA, named after the researchers that proposed it (Rivest, Shamir, and Adelman), is the most common example.
Public and private keys describe who has access to the key, rather than how they are used in encryption. A public key is known to everyone. This is the ‘commonly known’ key in the RSA description above. You won’t often see this in symmetric scenarios, due to the security risks. A private key is known only to you, or sometimes to a small number of people. This is the key type used in the DES and AES examples above, or the ‘unique key’ from the RSA description. As you might imagine, this is the most common type of key.