Ciphers

The Caesar cipher shifts the alphabet by any number of positions (1-25). ROT13 is a special case of the Caesar cipher with a shift of 13. ROT13 is convenient because applying it twice returns the original text: ROT13(ROT13(x)) = x.

Vigenère uses a keyword. Each letter in the text is shifted by the number corresponding to a letter in the key. The key repeats across the entire length of the text. This makes the cipher more secure than a simple Caesar cipher.

Atbash is an ancient Hebrew substitution cipher: A→Z, B→Y, Z→A. The alphabet is mirrored. Applying it twice returns the original text, as with ROT13.

No. Caesar, ROT13, Vigenère, and Atbash are classic ciphers that are easy to break. They’re useful for education and simple obfuscation, but not for protecting data. For real security, use AES or RSA.

Base64 encodes binary data as ASCII text. It is used in URLs, email, and JWT tokens. It can be decoded without a key; it does not encrypt data.