https://github.com/denatajp/hillchiper

Implementation of the Hill Cipher algorithm, a classical cryptography technique based on linear algebra. The project includes both encryption and decryption functions, utilizing matrix operations to transform plaintext into ciphertext and vice versa.
https://github.com/denatajp/hillchiper

python

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Implementation of the Hill Cipher algorithm, a classical cryptography technique based on linear algebra. The project includes both encryption and decryption functions, utilizing matrix operations to transform plaintext into ciphertext and vice versa.

• Host: GitHub
• URL: https://github.com/denatajp/hillchiper
• Owner: denatajp
• Created: 2024-08-24T02:47:57.000Z (10 months ago)
• Default Branch: main
• Last Pushed: 2024-08-24T04:01:48.000Z (10 months ago)
• Last Synced: 2025-04-14T20:38:46.508Z (2 months ago)
• Topics: python
• Language: Python
• Homepage:
• Size: 4.88 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        

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# Introduction

![image](https://github.com/user-attachments/assets/f3a85d50-9503-4056-a3c1-c22138909db3)

Hill Cipher is one of the classic cryptographic algorithms that utilizes the principles of linear algebra to encrypt and decrypt messages. It works by converting the original text (plaintext) into a numeric vector, then using a key matrix to multiply the vector. The result of this multiplication is a new vector which is then converted back into encrypted text (ciphertext). For the decryption process, the key matrix is inverted (inverse) and used to return the ciphertext to plaintext.

# Pros

- Math-Based Security: Hill Cipher offers strong security as it uses matrices and modular operations that make it difficult to crack with simple brute force methods.

- Simple and Efficient: The algorithm is relatively easy to understand and implement, making it suitable for basic learning purposes about cryptography.

- Resistance to Frequency Analysis: Since the Hill Cipher encrypts blocks of text at a time, this makes it more difficult to analyze using letter frequencies compared to a simple substitution cipher.

# Cons

- Keys Must Be Invertible: The key matrix used must have an inverse modulo 26, which means not all given keys will be valid for encryption and decryption.

- Vulnerable to Known-Plaintext Attacks: If an attacker has access to a pair of plaintext and corresponding ciphertext, they can attempt to reverse the key matrix.

- Limited to a Certain Block Length: Standard Hill Cipher implementations usually work on small blocks (such as 3x3), which can limit the length of messages that can be encrypted at once.

# How it works

## Encryption:

- The user enters the message and key.

- The message is broken into blocks of 3 characters.

- Each block is converted into a numeric vector, then multiplied by the key matrix.

- The result of the multiplication is converted back into encrypted text (ciphertext).

## Decryption:

- The user inputs the ciphertext and the key.

- The key matrix is inverted (inverse) for use in decryption.

- The ciphertext is broken into blocks, converted into a numeric vector, then multiplied by the inverse matrix.

- The result of the multiplication is converted back into the original text (plaintext).