What is the Atbash cipher?

The Atbash cipher is a simple substitution cipher where the letters of an alphabet are reversed. For example, in the Latin alphabet, 'A' is replaced by 'Z', 'B' by 'Y', and so on. It was originally used for the Hebrew alphabet but can be applied to any alphabet.

🔄 Atbash Cipher Decoder & Encoder Tool

Instantly translate text with the ancient Hebrew alphabet reversal cipher. Free, professional, and easy to use for decoding and encoding messages.

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📤 Output Text

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💡 Atbash Cipher Examples

Example 1: "HELLO" → "SVOOL" "HELLO" → "SVOOL"

Example 2: "CRYPTOGRAPHY" → "XIBKGLTIZKSB" "CRYPTOGRAPHY" → "XIBKGLTIZKSB"

Reverse Example: "GSV JFRXP YILDM ULD" → "THE QUICK BROWN FOX" "GSV JFRXP YILDM ULD" → "THE QUICK BROWN FOX"

🎯 Atbash Cipher Alphabet Table

Original: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Atbash: Z Y X W V U T S R Q P O N M L K J I H G F E D C B A

Understanding the Atbash Cipher

🏛️ What is Atbash Cipher?

The Atbash cipher is a simple substitution cipher from ancient Hebrew. It works by reversing the alphabet, so the first letter (A) is replaced by the last (Z), the second (B) by the second-to-last (Y), and so on. It requires no key.

🔓 How to Decode Atbash

Decoding is the same as encoding due to its symmetric nature. Simply apply the same alphabet reversal to the ciphertext. Since 'A' becomes 'Z', applying the cipher again makes 'Z' become 'A', restoring the original text.

📚 History & Origins

Originating around 500-600 BCE, it was used by Hebrew scribes. Its name comes from the first, last, second, and second-to-last Hebrew letters (Aleph, Tav, Bet, Shin). Its use in the Book of Jeremiah makes it one of the oldest known ciphers.

🛡️ Security Analysis

Atbash offers no cryptographic security. It has a fixed, keyless substitution, making it instantly recognizable and breakable. It is highly vulnerable to frequency analysis and is mainly used today for puzzles and educational purposes.

Frequently Asked Questions

How do you encrypt or decrypt with Atbash?

Encryption and decryption use the exact same process because the cipher is reciprocal (symmetric). You simply replace each letter in your message with its counterpart from the reversed alphabet. For instance, the plaintext "HELLO" becomes "SVOOL". To decrypt "SVOOL", you apply the same reversal, and it becomes "HELLO" again.

Is the Atbash cipher secure?

No, the Atbash cipher provides virtually no cryptographic security. Because its substitution method is fixed and has no key, it is trivial to break. Anyone familiar with basic ciphers can recognize and solve it instantly, and it is highly vulnerable to frequency analysis. It is primarily used for educational or recreational purposes today.

What is the relationship between the Atbash and Affine ciphers?

The Atbash cipher is a special mathematical case of the Affine cipher. In the formula for an Affine cipher, E(x) = (ax + b) mod m, Atbash is achieved when both 'a' and 'b' are set to m-1, where 'm' is the number of letters in the alphabet (e.g., 26 for English).

What are some famous examples of the Atbash cipher?

A classic text example is encrypting "ATTACK AT DAWN" which becomes "ZGGZXP ZG WZDM". Historically, it's one of the earliest known ciphers and appears in the Hebrew Bible (e.g., the Book of Jeremiah). In modern pop culture, it gained popularity from its use in the animated series Gravity Falls for some of the show's hidden messages and puzzles. for some of the show's hidden messages and puzzles.