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 an extent that it is no longer readable. The intent of encryption is hide and 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 information that is readable into 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. However, 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. Consider egg yolks as 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!

If you've never seen an egg yolk before, would you think that a plate full of scrambled eggs looked like egg yolk before? Pretty sure your answer would be 'no.' 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 undisclosed, meaning that the secret contents aren't exposed for those who aren't authorized to read it.

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 with. 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 can now encrypt and unencrypt messages that they weren't intended to see or mess with. To fix this problem, we use asymmetric keys.

Asymmetric Key - Bob is using Alice 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 to anyone - that's why it is called 'private'. Now each key can encrypt or unencrypt but cannot encrypt a message and then decrypt a message using the same key, unlike symmetric in which it can do both with the same key.

Using the example above, if Bob wants to send Alice an encrypted message which contains cheat codes to a game they're developing, he would grab Alice's public key and use that 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 has the private key and nobody else. It's very important that Alice doesn't give out her private key; she must always protect it. Why? Anyone can use a public key, remember?

All About Hash

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

Basically, the document would be processed by a hashing algorithm in which a fixed character length is produced. This fixed length value will never change unless the document somehow was changed. By hashing a document, you basically create a way to prove its authenticity. If someone else made 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 and that it's not authentic anymore.

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