維吉尼亞密碼

使用維吉尼亞多字母替換密碼搭配關鍵字進行文字加密和解密

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Vigenere Cipher

Encrypt or decrypt text using the Vigenere cipher with a keyword-based polyalphabetic substitution.

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Encrypt

Decrypt

Keyword

Enter keyword (letters only), e.g.: SECRET

Plaintext

Enter text to encrypt...

Ciphertext

Enter a keyword first

About the Vigenere Cipher

The Vigenere cipher is a polyalphabetic substitution cipher that uses a keyword to shift each letter differently. Each letter of the keyword determines the shift amount for the corresponding plaintext letter (A=0, B=1, ..., Z=25). The keyword repeats cyclically for longer messages. Non-alphabetic characters are passed through unchanged.