Practical Cryptography With Go

Introduction

The foundation of cryptographic security are the three goals of confidentiality, integrity, and authenticity.

Confidentiality is the requirement that only the intended party can read a given message; integrity is the requirement that a message’s contents cannot be tampered with; and authenticity is the requirement that the provenance (or origin) of a message can be trusted.

In order to discuss cryptography, a baseline vocabulary is needed. The following terms have specific meanings:

• The plaintext is the original message.

• The ciphertext is traditionally a message that has been transformed to provide confidentiality.

• A cipher is a cryptographic transformation that is used to encrypt or decrypt a message.

• A message authentication code (or MAC) is a piece of data that provides authenticity and integrity. A MAC algorithm is used both to generate and validate this code.

• To encrypt a message is to apply a confidentiality transformation, but is often used to describe a transformation that satisfies all three goals.

• To decrypt a message to reverse the confidentiality transformation, and often indicates that the other two properties have been verified.

• A hash or digest algorithm transforms some arbitrary message into a fixed-size output, also called a digest or hash. A cryptographic hash is such an algorithm that satisfies some specific security goals.

• A peer or party describes an entity involved in the communication process. It might be a person or another machine.

Engineering concerns and platform security

Basic security

Security should provide authentication, authorisation, and auditing. Authentication means that the system verifies the identity of parties interacting with the system; authorisation verifies that they should be allowed to carry out this interaction; and auditing creates a log of security events that can be verified and checked to ensure the system is providing security. The end goal is some assurance that the system is secure.