Let's look at the basic terminology related to cryptography:

• Cipher: An algorithm that performs a particular cryptographic function.
• Plain text: The plain data, which can be a text file, a video, a bitmap, or a digitized voice. In this chapter, we will represent plain text as P.
• Cipher text: The scrambled text that is obtained after applying cryptography to the plain text. In this chapter, we will represent this as C.
• Cipher suite: A set or suite of cryptographic software components. When two separate nodes want to exchange messages using cryptography, they first need to agree on a cipher suite. This is important in ensuring that they use exactly the same implementation of the cryptographic functions. 
• Encryption: The process of converting plain text, P, into cipher text, C, is called encryption. Mathematically, it is represented by encrypt(P) = C.
• Decryption: The process of converting cipher text back into plain text. Mathematically, it is represented by decrypt(C) = P.
• Cryptanalysis: The methods used to analyze the strength of the cryptographic algorithms. The analyst tries to recover the plain text without access to the secret.
• Personally Identifiable Information (PII): PII is the information that can be used to trace an individual's identity when used alone or with other relevant data. Some examples include protected information, such as a social security number, date of birth, or mother's maiden name.