Consider how many financial transactions are performed on the Internet everyday. Protecting all this data is of upmost importance. Cryptography can be defined as the process of concealing the contents of a message from all except those who know the key. Cryptography can be used for many purposes, but there are two types of cryptographic algorithms you need to understand, symmetric and asymmetric. Symmetric uses a single key, whereas asymmetric uses two keys. What else is required to have a good understanding of cryptography? It’s important to start with an understanding of how cryptography relates to the basic foundations of security: authentication, integrity, confidentiality, and non-repudiation.
- Authentication has several roles. First, authentication can also be associated with message encryption. Authentication is something you use to prove your identity, such as something you have, you know, or you are. Just as in the real world when you enter your username and password into an authentication system.
- Integrity is another important piece of the cryptographic puzzle. Integrity is a means to ensure that information has remained unaltered from the point it was produced, while it was in transmission, and during storage. In the real world integrity is proven with hashing algorithms.
- Confidentiality simply means that what is private should stay private. Cryptography can provide confidentiality through the use of encryption. Encryption can protect the confidentiality of information in storage or in transit. Encryption offers an easy way to protect that information should the equipment be lost, stolen, or accessed by unauthorized individuals.
- Non-repudiation is used to ensure that a sender of data is provided with proof of delivery and the recipient is assured of the sender’s identity. Neither party should be able to deny having sent or received the data at a later date. Today, the Internet makes many transactions faceless. You might never see the people you deal with, making non-repudiation even more critical. Non-repudiation is achieved through digital signatures, digital certificates, and message authentication codes (MACs).
These are the basic concepts used to secure data. In the world of cryptography, data that can be read and understood without any special measures is called plaintext. Whereas disguising plaintext to hide its true meaning is known as encryption. Encryption ensures that information is hidden from anyone it’s not intended for during storage or transit.
Understanding these concepts and the building blocks of cryptography will help as you examine more complex security tools and techniques. Modern cryptographic systems, such as PGP, TLS, IPSEC and others, use these basic concepts of cryptography.