Cryptography Terminology for Cybersecurity and CISSP

What is cryptography? Well, according to the website known as cryptography, when you are talking about the field of cybersecurity, cryptography is methods used "to secure information and communication techniques derived from mathematical concepts and a set of rule-based calculations called algorithms, to transform messages in ways that are hard to decipher". To put it in more simple terms for the layman so everyone reading this does not get confused, it is the art of using tech to turn sensitive information and communications into codes so they cannot be read on accident by those who are not supposed to get their hands on said information.

Cryptography, when you are talking about cybersecurity, includes a whole bunch of different terms that can easily get confusing. Fortunately, this article is here to make things easier and help you know some common terms that are used when related to cryptography in the field of information security.

One of the most important items when it comes to cryptography is you can create a formula to encrypt a message or piece of data to make it harder for someone to steal it and decrypt it. The name for this particular kind of formula is called an algorithm or a cipher. An algorithm also includes something called a key: a missing or hidden part of the formula that is kept by the user or company encrypting the data. A key is used to encrypt and/or decrypt the message, so as long as a hacker or attacker has no idea what the key is, they will not be able to decrypt the data and use this information to get access to important data that they should not. A system for a finance company or a new business that handles money, for example, might use a cipher for each of their customer's financial data when it is being sent over their network and a key or multiple keys might be assigned to financial data for encrypting this data and decrypting it when said data gets to its destination.

Plaintext is the term for data when it is not encrypted and put into a form that is easily comprehended by human beings or a computer system without needing to be decrypted. This kind of data is also known as cleartext. When the data is encrypted and is not readable by a person or a machine without needing to be decrypted, then it is known as ciphertext or a cryptogram.

Non-repudiation is defined as the inability to deny something. Part of the point of encryption is to be able to help identify who might have sent data, verify if the data was received by the intended target, and identify any thieves or hackers who might have taken information or manipulated this information while the data was in transit.

There are different forms of encryption and different ways an algorithm might mess around with the order or structure of a message/data to make it harder for someone to decrypt the information through blind luck. One method is substitution - when someone changes one character or symbol into another in a set pattern like changing every instance of a lowercase a into an exclamation point or substituting the letter g with the letter y in a message. You can also do transposition - reordering the characters or items in a message or piece of data without changing them. Then there is confusion - using multiple keys and changing what keys are used during multiple rounds of encrypting a message - and diffusion - switching around the location of plaintext within a cipher. With the right algorithm, you can do the avalanche principle - having an algorithm where a small change in plaintext creates a mostly different cipher.