Chapter 20. Secret Communication


  • Cryptography terminology

  • Exploring symmetric cryptography

  • Exploring asymmetric cryptography

  • Learning hash

  • Using and understanding common practices of encryption

Many people think of cryptography as spies trading secret messages written with strange symbols that only the author and recipient of the message can understand. Some have even heard of terms such as cipher text or public-key encryption, but can't readily explain what they are. There are a lot of terms in cryptography, and even more mathematics, making cryptography often confusing. A lack of understanding can create a situation where both parties believe they are communicating securely when in actuality they are not. This is why even a basic level of understanding of cryptography can be helpful.

While cryptography is a vast and complex subject, a little knowledge about the field can be very helpful with respect to security. While a lot of security is the process of putting up walls to prevent an attack, or managing risk when an attack occurs, cryptography plays an important role in an overall security scheme. In security, where little can be proven secure, it is nice to know that at least one tool, cryptography, has mathematical proofs backing up the level of security. However, as with anything in math, these proofs only apply in specific situations, and it is often the case that people try to bend protocols or use cryptographic primitives in ways for which they were never intended; ...

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