ROT13 ('Rotate by 13') is a simple 'substitution cipher' and a specific case of the Caesar cipher where the shift is 13 places. Each letter is replaced by the letter 13 positions after it in the alphabet (e.g., 'A' becomes 'N').

Is ROT13 a form of encryption? Is it secure?

No. ROT13 is **not** encryption, it is *obfuscation* (gizleme/karartma). It provides **zero security**. Since the key (13) is always known, anyone can reverse it instantly. It should *never* be used to protect sensitive data.

How do you encrypt and decrypt with ROT13?

That's the trick: they are the same operation. Because 13 is half of 26 (the number of letters in the alphabet), applying ROT13 to a piece of text and then applying it *again* returns the original text. (e.g., A -> N, and N -> A). You use the same function to both encode and decode.

ROT13 is used to hide text from a casual glance, most famously on old internet forums (Usenet) to hide **spoilers**, puzzle answers, or offensive jokes. It forces the user to make a conscious effort to 'decode' the text, preventing accidental reading.

ROT13 Translator (Rotate by 13)

Obfuscate or reveal text using the ROT13 cipher.

Input Text

Output

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What is ROT13 (Rotate by 13)?

**ROT13** (short for "Rotate by 13 places") is a simple letter substitution cipher. It is a specific example of the **Caesar cipher** which uses a fixed **shift of 13**.

In the standard 26-letter English alphabet, ROT13 works by taking a letter and replacing it with the letter 13 positions after it.

A ↔ N
B ↔ O
C ↔ P

The Key Property: It's Its Own Inverse
The magic of ROT13 is that 13 is exactly half of 26. This means if you apply ROT13 twice, you get back your original message.
Example: Hello → Uryyb
Example: Uryyb → Hello

Because of this, the "encrypt" and "decrypt" operations are identical.

Is ROT13 Secure?
**No. It provides zero security.** It is not a form of encryption, but rather **obfuscation** (gizleme/karartma). Since the key is public (it's *always* 13), anyone can reverse it instantly.

Why is it used?
ROT13's only purpose is to hide text from a casual, accidental glance. It was famously used on early internet forums (like Usenet) to:

Hide movie or book spoilers
Conceal puzzle answers or hints
Obscure the punchline of a joke

It forces the reader to make a conscious effort (like using this tool) to see the hidden message.

ROT13 Examples

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ROT13 Key Concepts & Best Practices

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Obfuscation, Not Encryption

ROT13 is **not security**. It's a "toy" cipher for hiding text from a casual glance. The key is always 13 and public knowledge. Never use it to protect passwords, secrets, or any sensitive data. For that, you must use **AES**.

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Encrypt = Decrypt

The most unique feature of ROT13 is that it's its own inverse. The function to encode text is the *exact same* as the function to decode it. This is because 13 + 13 = 26, a full rotation around the alphabet. ROT13(ROT13(text)) = text.

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Letters Only (Usually)

Standard ROT13 operates *only* on the 26 letters of the English alphabet (A-Z, a-z). All numbers, spaces, punctuation, and other characters are left completely unchanged. This makes it easy to apply and reverse without corrupting data structures.