Is XOR encryption secure?

No. A simple XOR cipher that uses a *repeating key* (like this tool) is **not secure**. It is very vulnerable to frequency analysis and known-plaintext attacks, and can be broken easily. It should only be used for simple obfuscation, not for protecting sensitive data.

What is a 'One-Time Pad' (OTP)?

A One-Time Pad is a *specific type* of XOR cipher that *is* theoretically unbreakable. Its security depends on three strict rules: 1) The key must be *truly random*. 2) The key must be *at least as long* as the message. 3) The key must be used *only once* (hence the name). Because managing and securely sharing such large, unique keys is impractical, OTPs are rarely used.

What is the difference between XOR and AES?

XOR is a simple, very fast logical operation. When used with a short, repeating key, it is insecure. AES (Advanced Encryption Standard) is a complex, modern encryption *algorithm* (block cipher) that is the global standard for security. AES is highly secure and has no known practical attacks. For any real security, you must use AES, not a simple XOR.

XOR Cipher Tool

Encrypt/Decrypt using a repeating-key XOR (For educational use).

Plain Text / Cipher Text

Mode

Key

Output

Your Security Matters: Client-Side Processing

All operations happen in your browser.
Your data, images, files, keys, or passwords are never stored or sent to our servers.
We don't track or monitor your generated content.

What is the XOR Cipher? (And Why Is It Insecure?)

The XOR cipher is a classical, symmetric encryption technique based on the **"Exclusive OR" (XOR)** logical operation. It's famous for its simplicity and for being the basis of the *only* theoretically unbreakable cipher: the One-Time Pad.

How XOR Works: XOR is a binary operation that results in `true` (1) only when its two inputs differ.

0 XOR 0 = 0
0 XOR 1 = 1
1 XOR 0 = 1
1 XOR 1 = 0

The magic property is that it's **reversible**: (A XOR B) XOR B = A.
To encrypt, you XOR the message with a key. To decrypt, you XOR the ciphertext with the *exact same key*.

The "Repeating Key" Problem (Why This Tool is Insecure)
This tool uses a **repeating key**. If your message is "HELLO WORLD" and your key is "KEY", the encryption is:
H E L L O _ W O R L D
K E Y K E Y _ K E Y K
This repetition is a *fatal security flaw*. It creates a pattern that can be easily broken with frequency analysis. This type of cipher is **not secure** and should never be used to protect real data.

XOR vs. The "One-Time Pad" (OTP): A One-Time Pad is an XOR cipher that *is* perfectly secure, but only if it follows three rules:

The key must be **truly random**.
The key must be **as long as the message**.
The key must be used **only one time** and then destroyed.

This tool is for educational purposes to demonstrate the XOR operation, not for real security. For security, use **AES**.

XOR Cipher Examples

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XOR Cipher Key Concepts & Warnings

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NOT FOR SECURITY

A repeating-key XOR cipher (like this one) is a "classical" cipher. It is **not secure** against modern attacks. It can be broken in minutes. This tool is for learning, not for protecting secrets. Use **AES-256** for real security.

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The "One-Time Pad" Paradox

The One-Time Pad (XOR with a long, random, non-repeating key) is the only *provably unbreakable* encryption. Its paradox is that it's completely impractical. Securely sharing a random key that is the same size as your message is usually harder than just sharing the message itself.

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XOR is Symmetric

The beauty of XOR is that the *same key* is used to encrypt and decrypt. Message XOR Key = Ciphertext. And Ciphertext XOR Key = Message. This is the definition of a symmetric cipher. It's also why the key must be kept absolutely secret.