Presidential candidates are talking about it. It’s all over the news. So you may be asking yourself, what is encryption? To understand encryption you must first think about how we communicate. In its most basic human form communication is done face-to-face through some kind of spoken or unspoken language. Two parties interact and data is exchanged. But what happens when a third party tries to get in on that exchange? You recall the old tin can telephone technique of your childhood? Imagine if someone tried to eavesdrop on your conversation. Well, not only is that very rude, but your nifty conversation is no longer very secure.
What Is Encryption?
Encryption is the process whereby a message or information is encoded so only authorized parties can read that data. Bob might still be able to listen in on Bill and Sally’s tin can conversation, but encryption would prevent him from deciphering what it all meant. If Bob doesn’t understand pig Latin, he’s up the creek without a paddle. Modern cryptography or the study of techniques for secure communication is based in mathematical theory and computer science study. At it’s core, an encryption scheme is one where the intended information, known as plaintext, is encrypted using an algorithm, generating ciphertext or encrypted text that can only be read if decrypted. Did you fall asleep? Let’s translate that in layman’s terms.
If you have a computer file on your desktop that you wish no one to have access to, then you’d most likely want to encrypt it. In order to open that file someone would then have to know the password you’ve set on the encrypted folder you’ve set up for that file to gain access to the information. In this case your data would be the plaintext. The computer has used a mathematical algorithm to encrypt the folder the data is contained in. So if you were to look at that folder that was encrypted it would look like a bunch of nonsense rather the word document you had stored in the folder. If the hacker were able crack the password aka ‘secret key’ they would then be decrypting the computer’s algorithm or cipher, thus accessing the data.
Types of Encryption
Let’s talk about two different types of modern encryption, symmetric key and asymmetric key. In symmetric key encryption the same cryptographic keys are used to encrypt information and then decrypt information between two parties. Both parties have access to the secret key. So, for example, Bob has an email message he’d like to send to Sally. Bob needs to lock that email message with a key. When that message reaches Sally, she uses an identical copy of the key that Bob has (perhaps transmitted via voicemail) to read the e-mail. So in essence, the key that both encrypts and decrypts the message would be known to Bob. Some common symmetric key encryption algorithms you may have heard of include DES, AES, and RC5.
Asymmetric key encryption, also known as ‘public key’ uses different keys for encryption and decryption of information. With asymmetric key encryption anyone has access to the encryption key to encrypt messages, but only the receiving party has access to the decryption key to read the messages. In this case, Bob and Sally don’t need identical copies of a key and there never needs to be that secret voicemail exchange. This prevents a third party from intercepting that secret key. So Bob encrypts his message for Sally using a public key. When Sally receives the message she decrypts it with her private key, which no one else would have access to. Examples of asymmetric encryption include RSA and DSA.
So it turns out encryption really isn’t a scary concept. It certainly gets more complicated but it’s still just a way to keep information safe and private. The more we continue to exchange information over e-mail, networks and beyond, the more encryption is a vital and valuable tool.