Cryptographic Concepts and Terms

Cryptography can be defined as the act or art of writing in secret characters. In technical jargon, it refers to the science and study of encrypting and decrypting information, identity verification and authorization, digital signatures, integrity checking, and secure computation. The following terms related to cryptography will aid in your understanding of later sections of this tutorial.

Plain-text

Plain-text describes the unencrypted payload; it refers to the original bits and bytes as they exist before they undergo any type of cryptographic transformation.

Note The term "plain-text" is somewhat of a misnomer, because the word "text" here does not necessarily refer to regular text-it can be any combination of bits and bytes.

If privacy or secrecy were not of concern in wireless communication systems, the steps involved in sending and receiving data would be very simple and straightforward: We'd simply start with plain-text at the sender end, that plain-text would be transmitted as is, and then we'd end up with plain-text at the receiver end. However, because secure communications are required between senders and receivers, encryption is added to the mix. We start off with plain-text at the sender end, the plain-text then undergoes some cryptographic transformation and manipulation (becomes cipher-text), the ciphertext is transmitted, the receiver gets the cipher-text and passes it through another cryptographic transformation or manipulation, and, finally, if the transformation process is successful, the original plain-text is derived and viewed by the receiver.

Note "Clear text" is another name for plain-text. It also means that the data is unencrypted.