What is Cryptography?
Tags: cryptography, encryption, decryption, infosectrain
Published: 2024-02-08 12:24:01


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## **What is Cryptography?**
Cryptography is a method used to secure communication and information between two parties by encrypting it using keys so that only the sender and intended receiver can read and comprehend the message. This ensures the confidentiality, integrity, and security of digital data from unauthorized users, often known as adversaries.

In computer science, cryptography refers to secure data and communication using a series of rule-based calculations known as algorithms to change messages into difficult-to-decipher (hard-to-read) formats. These algorithms generate cryptographic keys, digitally sign documents, verify data privacy, browse the web, protect private transactions, etc.

A cryptographic algorithm uses a key (secret key and public key), a string of bits, to convert plaintext to cipher text or vice versa. It is utilized to keep communication safe and secure between two parties.

The two most popular and crucial functions of cryptography are encryption and decryption.

Encryption encodes information from readable (plaintext) to unreadable (ciphertext) format using an encryption key and an encryption algorithm accessible only to authorized users.

Decryption decodes information from an unreadable (ciphertext) to a readable (plaintext) format using a decryption key and a decryption algorithm accessible only by authorized users.

## **Characteristics of Cryptography**
The following are some characteristics of cryptography:


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**Confidentiality:** Confidentiality implies that only the intended recipient can decrypt and understand the transmitted data.

**Integrity:** Integrity implies that information cannot be altered during storage or transmission between the sender and the intended recipient.

**Non-repudiation:** The sender cannot deny their reasons for sending a message in the future once the information has been conveyed.

**Authentication:** Authenticity implies that the sender and the intended recipient can authenticate each other's identities and the information's source or destination.

Check out our video on Cryptography:
https://youtu.be/jpZHds3Kvj4

## **Types of Cryptography**
Cryptography can be categorized into two types:

**1. Classic Cryptography:** It refers to the historical methods and techniques of encryption used before the advent of computers and modern cryptographic algorithms. It can be divided into subtypes, including:
**• Caesar Cipher**: A substitution cipher in which each letter is shifted to a fixed number of positions.
**• Vigenere Cipher**: A polyalphabetic substitution cipher that uses multiple Caesar ciphers based on a keyword.
**• Playfair Cipher**: A substitution cipher that uses a 5x5 matrix of letters to encrypt pairs of letters.
**• Rail Fence Cipher**: A transposition cipher that writes the message in a zigzag pattern.
**• Transposition Cipher**: Rearranges characters to encrypt plaintext messages.
**• Atbash Cipher**: Substitutes each letter with its reverse alphabet counterpart.

**2. Modern Cryptography:** It refers to the cryptographic algorithms and techniques developed since the mid-20th century with the advancements in computing technology. It can be divided into subtypes, including:
**• Symmetric Key Cryptography:** Utilizes a single secret key for both encryption and decryption, such as AES.
**• Asymmetric Key Cryptography:** Utilizes key pairs (public and private keys) for encryption and decryption, like RSA.
**• Hash Functions:** Generate fixed-size hash values to verify integrity and create digital signatures.
• [Digital Signatures](https://infosec-train.blogspot.com/2022/12/what-is-digital-signature.html): Provide authentication and integrity using asymmetric encryption and hash functions.
**• Key Exchange Algorithms**:Enable secure key exchange over insecure channels, such as Diffie-Hellman and ECDH. 

**Feel free to explore related articles:**
●      [Encryption Vs. Encoding](https://www.infosectrain.com/blog/encryption-vs-encoding/)

●      [What is a Cipher in Cryptography?](https://infosec-train.blogspot.com/2023/03/what-is-cipher-in-cryptography.html)

●      [Hashing vs. Encryption](https://infosec-train.blogspot.com/2022/05/hashing-vs-encryption.html)

●      [Cryptography in Cyber Security ](https://infosec-train.blogspot.com/2023/03/cryptography-in-cyber-security_01463800002.html)

## **Cryptography with InfosecTrain**
Cryptography has become increasingly prevalent in the digital market in recent years. If you want to learn cryptography in detail, you can enroll in [InfosecTrain](https://www.infosectrain.com/)'s [Network Security](https://www.infosectrain.com/courses/network-security-training/), [Ethical Hacker Training](https://www.infosectrain.com/courses/certified-ethical-hacker-ceh-training/), training courses. The course provides a strong understanding of the core concepts of cryptography.