Caesar Cipher
Explore an educational Caesar shift or ROT13 with explicit encoding and decoding controls.
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How to use Caesar Cipher
Learn how a fixed alphabet rotation transforms English letters. Shift 13 gives ROT13; punctuation, numbers, emoji, and other scripts remain unchanged.
- Enter text and an integer shift.
- Choose encode or decode; choose shift 13 for ROT13.
- Run and compare the rotated letters with the original.
Good to know
- Educational obfuscation only. Caesar shifts and ROT13 provide no confidentiality, authentication, or modern cryptographic security.
- Only ASCII A–Z/a–z rotate. Shifts wrap modulo 26 and preserve case.
Common questions
Why does applying ROT13 twice restore the text?
Two shifts of 13 complete a 26-letter rotation.
Can this protect a password or secret?
No. Anyone can reverse the tiny set of shifts; use established cryptographic systems for protection.
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