The Art of Cryptography

Why Cryptography?

How would you feel about strangers reading your email or personal messages?

Or if, a random person wanders around the internet pretending to be you.

Even worse, what if someone could access your bank account when they need a little extra cash?

Sounds disturbing, right?

In today’s world, a vast majority of people interact electronically through various means like emails, social media, ATMs, e-commerce, and mobile phones on a day to day basis.

The rapid increase in the amount of information transmitted electronically in recent years resulted in widespread use of digital security features like cryptography and authentication.

Cryptography is the means by which security for information and resources is enforced using various encryption methods and strategies.

What is Cryptography?

In general, the art and science of concealing the messages to introduce secrecy in communication are known as cryptography.

The word cryptography is derived from the Greek words Krypto meaning hidden and Graphene meaning writing.

In the field of information security,Cryptography can be defined as

" The art and science of applying complex mathematics and logic to design strong encryption methods."

Encryption and decryption play a significant role in cryptography and aim at rendering data unreadable to unauthorized personnel.

In its simplest form, cryptography is the art of transforming information in a such a way that an adversary cannot access it in an understandable form.

The Essence of Cryptography

Cryptography in the digital world offers four core areas that protect data from unauthorized access and manipulation.

Integrity : Ensures that information has not been altered in any unauthorized ways by any means.

Confidentiality : Ensures only authorized users can access sensitive and protected data.

Authentication : Ensures that a message originated from its claimed originator.

Non-repudiation : Ensures the authenticity of personnel involved in the manipulation of information.

Basic Cryptographic Terms

Before we dive deep, let's understand some of the widely used terms in the field of cryptography.

Plaintext: The original, readable message or data without much processing.

Encryption: The process of transforming information into an unintelligible format using an algorithm and key.

Ciphertext: The unintelligible message obtained after the encryption process.

Decryption: The process of retrieving the original plaintext from the ciphertext using the key and decryption algorithm.

Key: Sequence of characters consisting of numeric, alpha-numeric and optionally special characters, used to encrypt/decrypt a message.

Cryptography: An Overview

The above picture provides a simple overview of cryptography based on the basic terms of cryptography.

Cryptography: Classification

Most of the widely used cryptographic algorithms fall under either of the categories: Symmetric or Asymmetric Cryptography.

Symmetric vs Asymmetric Cryptography

In general, encryption algorithms are classified into two broad categories based on the type of keys used.

Symmetric Cryptography : In these algorithms, the same key is used for encryption and decryption.Hence, the key has to be shared between the sender and receiver beforehand.

Asymmetric or Public Key Cryptography: Asymmetric Encryption Algorithms make use of two keys: a public key and a private key.As evident from the names, the public key can be shared, but the private key has to be kept confidential.

Cryptography in Ancient Times

The earliest encryption attempt known to mankind dates back to the era of ancient Egypt, almost 2000 years before Christ.

The tomb of Khnumhotep II is found to be engraved with ciphers.