Vigenere Cipher
Vigenere cipher encoder/decoder with key validation and case preservation.
Effective Key: -Length: 0
Input Text0 chars
Output0 chars
What is Vigenère Cipher?
The Vigenère cipher is a polyalphabetic substitution cipher that uses a repeating key to shift letters.
The key repeats as needed. Non-letter characters are preserved and do not advance the key.
About This Tool
The Vigenere cipher is a classic polyalphabetic substitution cipher that uses a repeating key to shift letters. This tool supports encode/decode modes, auto-filters non-letter characters in the key, preserves case and symbols, and shows real-time results with one-click copy. All processing stays local in your browser.
Features
- 🔄 Encode/Decode Modes: Bidirectional conversion with instant output
- 🧩 Key Validation: Auto-clean non-letter characters and show effective key
- 🔤 Case Handling: Preserve original case or normalize output case
- 🧷 Symbol Preservation: Keep non-letter characters as-is
- 📋 Copy & Swap: One-click copy and input/output swap
- 🔒 Local Processing: All computation stays in your browser