Except explicit open source licence (indicated CC / Creative Commons / free), any 'Affine Cipher' algorithm, applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any 'Affine Cipher' function (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode. It is a cipher key, and it is also called a substitution alphabet. For a simple substitution cipher, the set of all possible keys is the set of all possible permutations. Thus, for the English alphabet, the number of keys is 26! (factorial of 26), which is about. Because of this, if you want to decipher the text without knowing the key, the.
Using The Atbash Cipher Decoder
The atbash cipher is a simple substitution cipher from Biblical times; it reverses the alphabet such that each letter is mapped to the letter in the same position in the reverse of the alphabet (A -> Z, B -> Y). The original implementation (ca. 500 BC) was for the Hebrew alphabet and there are Old Testament references to it. The Atbash cipher has also been associated with various forms of mysticism. In modern times, it is referred to as a reverse alphabet code (see these cubscout materials). The atbash cipher is trivial to crack, once you realize that you're dealing with a substitution cipher, and is highly vulnerable to letter frequency analysis. It's primary modern application is puzzles and games. This atbash translater (including both atbash encoder and atbash decoder) can help you decode these cipher messages.
This tool is an atbash decoder; it is also an atbash encoder, since the two are exactly identical. To use the atbash translator to translate a message (atbash encoder setting), paste your message into the text box and hit translate message. The result will appear below. To decipher the atbash cipher message, copy the text from the results box into the text box (which serves as the atbash encoder) and hit translate message. You should be looking at your original text.
For a low-tech cipher, the atbash cipher is surprisingly effective. While it relies completely upon suprise (hint: don't use it to encode truly secret messages), most decoders mentally try the caesar cipher (fixed letter shift), which fails, and assume a mixed alphabet cipher. This is a much more complicated cipher to attack, even with a computer. So don't laugh at the atbash encoder and atbash decoder - they may be rustic, but they are certainly enough to confuse most of the people some of the time. Granted the task of an atbash decoder was harder before computer automation.
We also have a Substitution Cipher Workbench which can encode and decode messages using more complicated monoalphabetic ciphers, a Caesar Cipher Decoder, and a decoder for Rot13 Encryption.
Cipher Decoder: Broader Perspective
The first cipher use in recorded history to protect information was in Mesopotamia. We've found some clay tablets that were clearly designed to protect information. Military and diplomatic use of ciphers picked up around 500 - 400 B.C., with documented cipher use in many areas of the world (Greeks, Hebrew, India).
The Atbash cipher is one of the easiest cipher systems out there; the atbash ciphertext is trivial to decrypt once you understand the pattern. The Rot13 cipher, A1Z26 cipher, morse code, and affine cipher, while an artifact of the machine age, are similarly trivial to solve. From there you move to a full monoalphabetic cipher, with a more complex monoalphabetic substitution system to jumble the secret message. Modern cryptogram puzzles are based around a monoalphabetic substitution cipher. Solving the puzzle involves mapping the ciphertext alphabet to the plaintext alphabet.
As experienced cryptogram solvers know, the decryption weakness of a substitution cipher that maintains the same basic message structure in the plaintext letter. For example, single letter clues such as the first letter, second letter, and last letter of a word restrict the range of possible words and facilitate guessing. Punctuation helps as well.
There are several options for making a cipher harder, beyond the ability of most human analysts to crank. The first is to layer a shift cipher into the system, so word patterns are obscured. The other is to use multiple alphabets and rotate between them (this is the basis of a polyalphabetic cipher system such as the vigenere cipher. The combined cipher is better protected, since it is far harder to crack both coding systems at once.
Need more? Check out our word scramble solver.
Encryption with Vigenere uses a key made of letters (and an alphabet). There are several ways to achieve the ciphering manually:
Vigenere Ciphering by adding letters
In order to cipher a text, take the first letter of the message and the first letter of the key, add their value (letters have a value depending on their rank in the alphabet, starting with 0). The result of the additionmodulo 26 (26=the number of letter in the alphabet) gives the rank of the ciphered letter.
Example: To cryptDCODE, the key is KEY and the alphabet is ABCDEFGHIJKLMNOPQRSTUVWXYZ.
Example: Take the first letters of the plaintext D (value = 3) and of the key K (value = 10) and add them (3+10=13), the letter with value 13 is N.
Continue with the next letter of the plaintext, and the next letter of the key. When arrived at the end of the key, go back to the first letter of the key.
Example:DCODE
KEYKE
Example:NGMNI is the ciphertext.
Vigenere Cipher using a table
In order to encrypt using Vigenere method, the easiest way is to have a double entry grid, here is one (when the alphabet is ABCDEFGHIJKLMNOPQRSTUVWXYZ):
Example: The key is KEY, and the plaintext is DCODE.
Substitution Cipher Solver Tool
Locate the first letter of the plaintext message in the first line of the table and the first letter of the key on the left column. The cipher letter is at the intersection.
Example: Locate the letter D on the first row, and the letter K on the first column, the ciphered letter is the intersection cell N.
Cipher Decryption Tool Online
Continue with the next letter of the plaintext, and the next letter of the key. When arrived at the end of the key, go back to the first letter of the key.
Cipher Decryption Tool
Example:NGMNI is the ciphertext.