Cryptography Tutorial

Cryptography is a technique of securing communication by converting plain text into unintelligible ciphertext. It involves various algorithms and protocols to ensure data confidentiality, integrity, authentication, and non-repudiation. The two primary types of cryptography are symmetric key cryptography and asymmetric key cryptography and It plays a vital role in ensuring the security and privacy of information in today’s digital world and enables secure online transactions, protects sensitive data stored in databases, and ensures the confidentiality of communication. As technology continues to advance, cryptography remains a crucial tool in the ongoing battle to keep our information safe from hackers.

In this Cryptography Tutorial, we’ve covered basics and advanced concepts of Cryptography including symmetric-key cryptography, asymmetric-key cryptography as well as Cryptanalysis, Public Key Cryptography and more. It provides a solid foundation in the core concepts of cryptography, as well as insights into its practical applications.

By the end of this tutorial, you will have a basic understanding of how cryptography works and how it can be used to protect your information.

What is Cryptography?

Cryptography is a technique of securing information and communications through the use of some algorithms so that only those persons for whom the information is intended can understand it and process it.

Cryptography Tutorial Index

Here are the latest topics of cryptography(basics to advanced):

Cryptography – Table of Content

• Introduction
• Types of Cryptography
• Data Encryption Standard (DES)
• Advanced Encryption Standard (AES)
• Public Key Cryptography Algorithms and RSA
• Cryptology, Cryptography and Cryptanalysis
• Common Used Cryptography Techniques
• Data Integrity in Cryptography
• Important Difference b/w topics of Cryptography

Introduction

• Introduction to Cryptography
• History of Cryptography
• Cryptography Principles
• Cryptography and its types
• Advantages and Disadvantages of Cryptography
• Applications of Cryptography
• What is Cryptosystem?
• Components of Cryptosystem
• Attacks on CryptoSystem

Types of Cryptography

• Symmetric Key Cryptography
  • Stream Cipher
  • Block Cipher
  • Substitution techniques
    • Ceaser Cipher
    • MonoAlphabetic Cipher
    • Playfair Cipher
    • Hill Cipher
    • Polyalphabetic Cipher
    • One-Time Pad
  • Transposition Techniques
    • Rail Fence Cipher
    • Columnar transposition
  • Steganography
• Asymmetric Key Cryptography
  • Rivest-Shamir-Adelman (RSA)
  • Diffie-Hellman key exchange
  • Digital Signature Standard (DSS)
• Hash Functions

Data Encryption Standard (DES)

• What is data encryption?
• Encryption Algorithms
  • SHA
  • RC4
  • Hash Functions
  • BLOWFISH
• Strength of Data encryption standard (DES)
• Double DES and Triple DES
• Difference between MD5 and SHA1
• Difference between RSA algorithm and DSA
• Difference between RSA and Diffie-Hellman

Advanced Encryption Standard (AES)

• Introduction to AES
• AES Structure
• AES Transformation Function
  • Substitute Bytes Transformation
  • ShiftRows Transformation
  • MixColumns Transformation
  • AddRoundKey Transformation
• AES Key Expansion Algorithm
• AES Examples
• Implementation of AES
• Difference between AES and DES ciphers

Public Key Cryptography Algorithms and RSA

• What is Public Key Cryptography?
• Four asymmetric public-key algorithms
  • Rivest-Shamir-Adleman (RSA)
  • Elliptic Curve Digital Signature Algorithm (ECDSA)
  • Digital Signature Algorithm (DSA)
  • Diffie-Hellman key agreement protocol

Cryptology, Cryptography and Cryptanalysis

• Introduction to Cryptology
• Types of Crptology
  • Cryptography
  • Cryptanalysis
    • Introduction to Cryptanalysis
    • Types of Cryptanalytic Attacks
      • Rainbow table attack
      • Dictionary attack
      • Brute force attack
• Cryptology v/s Cryptography
• Cryptography v/s Cryptanalysis
• Cryptology v/s Cryptanalysis

Common Used Cryptography Techniques

• Custom Building Cryptography Algorithms (Hybrid Cryptography)
• An Overview of Cloud Cryptography
• Quantum Cryptography
• Image Steganography in Cryptography
• DNA Cryptography
• One Time Password (OTP) algorithm in Cryptography
• Modern Cryptography

Data Integrity in Cryptography

• Cryptography Hash functions
• Message Authentication
• Cryptography Digital signatures
• Public Key Infrastructure

Important Difference b/w topics of Cryptography

• Classical Cryptography and Quantum Cryptography
• Difference between Steganography and Cryptography
• Difference between Encryption and Cryptography
• Difference between Cryptography and Cyber Security
• Difference between Hash functions, Symmetric, and Asymmetric algorithms
• Difference between Stream Cipher and Block Cipher

Features of Cryptography

Below are some features of cryptography:-

• Confidentiality: Cryptography keeps your sensitive information hidden from hackers by transforming it into an unreadable form.
• Integrity: Cryptography ensures that your data remains intact and unaltered during transmission or storage.
• Authentication: Cryptography helps verify the identity of a sender and confirms the origin of a message.
• Non-repudiation: Cryptography prevents the sender from denying their involvement in a message or transaction.
• Key Management: Cryptography securely manages the keys used for encryption and decryption.
• Scalability: Cryptography can handle different levels of data volume and complexity, from individual messages to large databases.
• Interoperability: Cryptography allows for secure communication between different systems and platforms.
• Adaptability: Cryptography continuously evolves to stay ahead of security threats and technological advancements.

How Cryptography Works?

■ Plaintext: This is the original intelligible message or data that is fed into the algorithm as input.

■ Encryption algorithm: The encryption algorithm performs various substitutions and transformations on the plaintext.

How Cryptography works?

■ Secret key: The secret key is also input to the encryption algorithm. The key is a value independent of the plaintext and of the algorithm. The algorithm will produce a different output depending on the specific key being used at the time. The exact substitutions and transformations performed by the algorithm depend on the key.

■ Ciphertext: Ciphertext is the scrambled message produced as output. It depends on the plaintext and the secret key. For a given message, two different keys will produce two different ciphertexts. The ciphertext is an apparently random stream of data and, as it stands, is unintelligible.

■ Decryption algorithm: This is essentially the encryption algorithm run in reverse. It takes the ciphertext and the secret key and produces the original plaintext.

For Example:- Let’s say you want to send a secret message to your friend. You could write the message on a piece of paper and seal it in an envelope. However, if someone intercepted the envelope, they could open it and read the message. Instead, you could encrypt the message using a cryptographic algorithm. This would transform the message into ciphertext that is unreadable by unauthorized individuals. 

You could then send the ciphertext to your friend, who could decrypt it using the same cryptographic algorithm and key. The security of a cryptographic system depends on the strength of the cryptographic algorithm and the secrecy of the keys. If the cryptographic algorithm is weak, then it may be possible to break the encryption and read the plaintext. If the keys are not kept secret, then they may be compromised, which would allow unauthorized individuals to decrypt the ciphertext.

Applications of Cryptography

• Uses: Cryptography finds extensive application in various fields to ensure data security and protect sensitive information.
• Secure Communication: Cryptography enables secure communication channels, such as encrypted messaging apps and virtual private networks (VPNs), to protect conversations and data transmitted over the internet.
• E-commerce and Online Transactions: Cryptography is crucial in securing e-commerce transactions, online banking, and digital payment systems. It protects sensitive financial information, such as credit card details and personal identification numbers (PINs).
• Password Storage: Storing passwords securely is essential to prevent unauthorized access to user accounts. Cryptographic techniques like hashing and salting help protect passwords from being easily compromised in the event of a data breach.
• Digital Rights Management (DRM): Digital Rights Management (DRM) systems use cryptography to enforce copyright protection and prevent unauthorized copying or distribution of digital content, such as e-books, music, and movies.

FAQs on Cryptography

1. What is the purpose of cryptography?

The purpose of cryptography is to secure and protect sensitive information by encoding it in a way that only authorized parties can understand.

2. How does asymmetric key cryptography work?

Asymmetric key cryptography works by using a pair of mathematically related keys: a public key for encryption and a private key for decryption.

3. Which are the commonly used symmetric key algorithms?

Commonly used symmetric key algorithms include AES (Advanced Encryption Standard), DES (Data Encryption Standard), and 3DES (Triple Data Encryption Standard).

4. Can quantum computers break existing cryptographic systems?

Quantum computers have the potential to break existing cryptographic systems due to their ability to solve certain mathematical problems much faster than traditional computers.

5. How is cryptography used in e-commerce transactions? give answers to these questions in one line

Cryptography is used in e-commerce transactions to encrypt sensitive data, such as credit card information, during transmission to ensure its confidentiality and integrity.