What Is Cryptography?

Date First Published: 8th February 2024

Topic: Cybersecurity

Subtopic: Security Mechanisms & Technologies

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 4/10

CONTENTS

Cryptography Techniques
Cryptography Principles
Cryptography Issues
History

Learn about what cryptography is in this article.

Cryptography is the practice of securing information by transforming it into a secure format. This ensures that only the person who is meant to see the information can view it and no unintended recipients can understand it. Cryptography is important for data protection, confidentiality, data integrity, and authentication.

Cryptography Techniques

Cryptography includes techniques, such as microdots, merging words with images, and other ways to hide information when stored or transmitted. Examples of cryptography techniques include:

Hashing - Algorithms are used to protect passwords. Plaintext is transformed into a unique and irreversible ciphertext.
Symmetric encryption - Also known as private key encryption, symmetric encryption is when a single key is used to encrypt and decrypt a message and all parties use the same key. Stored data is usually encrypted using symmetric encryption.
Asymmetric encryption - Asymmetric encryption consists of two keys, called the public and private keys. The public key is available to anyone who wants to encrypt a message to a recipient. Data sent during transmission is usually encrypted using asymmetric encryption.

Cryptography Principles

Principles of cryptography include:

Data confidentiality - The information cannot be understood by any unintended recipients.
Data integrity - Maintaining and ensuring that data remains accurate and consistent. For example, information should not be tampered with when stored or during the transmission process between the sender and receiver.
Authentication - Verifies the identity of clients sharing data and that they are who they claim to be. This proves that the information being claimed by the client actually belongs to them.
Non-repudiation - Ensuring that someone associated with data cannot deny the authenticity of their signature over their document or transmission of the message.

Cryptography Issues

Attackers can bypass cryptography using brute-force attacks and gain unauthorised access to computers that are responsible for encryption and decryption. Since computers can process billions of calculations per second, they can even break complex algorithms within a few seconds. However, cryptography makes it harder for attackers to access messages and data protected by encryption algorithms. Modern cryptography involves developing encryption algorithms that are difficult for even the most powerful computers to crack.

Difference Between Cryptography and Encryption

The main difference between cryptography and encryption is that cryptography is the science of securing information by transforming it into a secret code, whilst encryption is a method of encoding sent information into random characters and symbols. Encryption is just one form of cryptography.

History

Before the modern era, cryptography focused on message confidentiality. This included the conversion of messages from a readable form into an unreadable one. This ensures that it cannot be read by interceptors or eavesdroppers without secret knowledge (namely the key needed for decryption of that message). Encryption attempted to ensure secrecy in communications, such as those of spies, military leaders, and diplomats.

In the last few decades, cryptography has expanded beyond confidentiality concerns to include techniques for message integrity checking, sender/receiver identity authentication, digital signatures, interactive proofs, secure computation, and more.