What is the Vigenere cipher?

The Vigenere cipher is a polyalphabetic substitution scheme that shifts letters according to a repeating keyword. Each character of the key selects a different Caesar shift, making the pattern far harder to spot than a single fixed rotation. Historically it was considered "unbreakable" until analysts used frequency analysis on repeated key cycles, which is why it still serves as a foundational lesson in classical cryptography.

Tool description

Encode or decode passages with a customizable keyword using the caesar-salad implementation of the Vigenere cipher. Letters rotate based on the key while punctuation, digits, and spacing remain untouched so the output stays readable.

Features

  • Keyword input that accepts only letters and normalizes them automatically
  • Instant encryption and decryption powered by the caesar-salad Vigenere engine
  • Preserves whitespace, numbers, and punctuation while rotating alphabetic characters
  • Works seamlessly with mixed uppercase and lowercase messages

Use Cases

  • Teaching polyalphabetic substitution in classrooms or study groups
  • Solving puzzle hunts or escape-room challenges that rely on Vigenere clues
  • Checking homework answers or self-study practice for cryptography courses
  • Obfuscating text snippets in prototypes, brainstorming, or low-stakes communication