What is Encryption? - Definition, Types & Methods

Instructor: Raymond Blockmon

Raymond has earned a bachelor's degree in computer information systems and a master's degree in organizational leadership.

Encryption is the process of taking a readable plain text document or image and scrambling that document or image to the extent that it is no longer readable. The intent of encryption is to protect the contents of that file from improper disclosure.

What is Encryption?

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Basically, encryption is making sure that you're keeping a secret, well, a 'secret'! Shhh...

More to the point, encryption is the process of hiding readable information in a format that can't be read. Encryption can be used for many different things, but you're probably most familiar with its function of transferring information securely. In this lesson, we'll go over all the big stuff: symmetric and asymmetric encryption, digital signature, and hashing encryption methods.

Bulk Encryption: Making a Mess Out of Big Data

Encryption is like making scrambled eggs. The egg yolks are like a readable plain text document that becomes scrambled, or encrypted, to something completely different and unrecognizable, which is called cipher text. Plain text is a readable format and cipher text is a format that becomes unreadable. In other words, everything is scrambled!

Think about what an egg yolk looks like. Now, if you have a plate full of scrambled eggs can you easily imagine that they looked like a bunch of egg yolks before being scrambled? It might be difficult. Now imagine taking a large media file, like a Blu-Ray movie, and encrypting that movie to a format that can't be read. We use encryption to protect the contents from being disclosed, meaning that the secret contents aren't exposed to those who aren't authorized to them.

In order to encrypt and unencrypt data, you need to have a symmetric or shared key. A shared key is a key that one or two people will use to encrypt the message. You can also use the key to unencrypt as well. The problem with symmetric keys is key management. Look at this way: because two people know the same key, all it takes is one of them losing their key. If that happens, a person with evil intentions could discover it. Then that evildoer could encrypt and unencrypt messages that they weren't intended to see. To fix this problem, we use asymmetric keys.

Asymmetric Key - Bob is using the public key to encrypt a message. Alice uses her private key to unencrypt and read the message.
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Asymmetric keys consist of a public key and a private key. The public key is made available for anyone to use, hence the name 'public.' The private key is the key that only the owner knows and does not share with anyone - that's why it is called 'private'. Now, each key can encrypt or unencrypt but you cannot encrypt a message and then decrypt it using the same key, unlike symmetric encryption where you can do both with the same key.

Using the example above, if Bob wants to send Alice an encrypted message which contains the cheat codes to a game they're developing, he would use Alice's public key to encrypt his message. After doing so, he then sends the encrypted message to Alice. Once Alice receives the encrypted message, she is the only one who can unencrypt the message and read the cheat codes because she is the only one who has the private key. It's very important that Alice doesn't give out her private key; she must always protect it. Why? Remember, anyone can use a public key.

All About Hash

We're not talking about breakfast here! Hash is an encryption method that we use to provide message integrity. When we want to send a document and ensure to the recipient that nothing has changed, we can 'hash' the document. Hashing is a one-way encryption method, meaning that you can't reverse the hash.

Basically, the document is processed by a hashing algorithm in which a fixed character length is produced. This fixed length value will never change unless the document is somehow changed. By hashing a document, you basically create a way to prove its authenticity. If someone else makes any changes to that document and hashes it, a completely different fixed length value will occur. If you compare the original hash and the newly created hash, you will know that the document has been changed.

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