Guide to Cryptography for CISSP

What is Cryptography?
Cryptography is the practice and study of techniques to secure communications in the presence of adversaries. It is a method of protecting information and communications by transforming the original representation of the information, known as plaintext, into an alternative form known as ciphertext.

Why is Cryptography Important?
Cryptography plays a vital role in information security. It provides the necessary tools for privacy, confidentiality, data integrity, non-repudiation, and authentication. Without the use of cryptography, data sent via internet can be intercepted and read by anyone.

How does Cryptography Work?
Cryptography works by using algorithms and mathematical equations to secure communications. An algorithm is used to transform plaintext into ciphertext (encryption) and then back into plaintext (decryption).

Exam Tips: Answering Questions on Cryptography
1. Understand the Basic Concepts: It is essential to have a clear understanding of basic cryptography concepts such as symmetric and asymmetric encryption, hash functions, and digital signatures.
2. Practice with Real-World Examples: Understanding how cryptography is applied in real-life scenarios can help answer exam questions.
3. Know the Algorithms: Be familiar with basic cryptographic algorithms such as DES, RSA, AES and HMAC.
4. Understand Key Management: Key management, including key exchange, storage, and the lifecycle of cryptographic keys, is often a critical part of the exam.
5. Think Like a Cryptographer: Remember that the primary goal of cryptography is to ensure data confidentiality, integrity, and authenticity. Try to understand not only how the puzzles are put together, but also why they are assembled in that way.