https://github.com/dmlen/vigenerec

A C++ implementation of the Vigenère cipher
https://github.com/dmlen/vigenerec

cipher cipher-algorithms cplusplus cpp encryption encryption-algorithms encryption-decryption vigenere vigenere-cipher vigenere-decoder

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A C++ implementation of the Vigenère cipher

• Host: GitHub
• URL: https://github.com/dmlen/vigenerec
• Owner: DMLen
• Created: 2024-09-02T13:23:06.000Z (4 months ago)
• Default Branch: main
• Last Pushed: 2024-09-05T01:52:17.000Z (4 months ago)
• Last Synced: 2024-10-20T08:10:30.690Z (2 months ago)
• Topics: cipher, cipher-algorithms, cplusplus, cpp, encryption, encryption-algorithms, encryption-decryption, vigenere, vigenere-cipher, vigenere-decoder
• Language: C++
• Homepage:
• Size: 18.6 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# VigenereC

*A C++ implementation of the Vigenère cipher as described at [Wikipedia](https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher)*

"...each letter of the plaintext is encoded with a different Caesar cipher, whose increment is determined by the corresponding letter of another text, the key."

This is a text encoder/decoder that is capable of encrypting and decrypting plaintext with a supplied key using Vigenère's cipher, which is based upon the Caesar cipher method of shifting/rotating letters. This implementation is NOT case-sensitive, and spaces are not counted in the provided key.

The program itself is a simple commandline tool. Compile the cpp code and run it, or find a pre-built .exe file in the releases tab.

Verify results against [University of Denver's Vigenère encoder/decoder](https://www.cs.du.edu/~snarayan/crypt/vigenere.html)

(Note: In each of these cases, the Key is used to encrypt as well as decrypt. Whitespaces and upper/lowercase are filtered out and ignored by this program.)

| Plaintext  | Key | Ciphertext |

| ------------- | ------------- | ------------- |

| attacking tonight | OCULORHINOLARINGOLOGY | ovnlqbpvt hznzouz |

| Humpty Dumpty sat on a wall | egg | lastze hastze wgz st g agrp |

| Humpty Dumpty sat on a wall | The egg fell | abqtze iyxamf wez us e hles |

| abcdefg | 1 | bcdefgh |

| abcdefg | 10 | bbddffh |

In the example where keytext is "1", inputting a key of just one produces a caesar cipher by shifting each letter of the plaintext forward by that amount. A keytext of "10" DOES NOT result in a shift of 10, as the Vigenère algorithm considers each digit to be its own thing.