Number to Letter A1Z26 Converter

1. Substitution Cipher Solver Tool
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4. Substitution Cipher Solver Tool

Letter to Number A1Z26 Encoder

Calculate a word's value

Key in a word or a short phrase in the top box. Enter a Keyword. Press Encipher or Decipher. The results appear in the bottom box. The Keyword Cipher uses a Keyword to rearrange the letters in the alphabet. These different letters are then substituted for the letters in the message to create a secret message. Cipher Tools Let's say that you need to send your friend a message, but you don't want another person to know what it is. You can use a full-blown encryption tool, such as PGP. If the message isn't that important or if it is intended. ACA Convention Registration. Vote On ACA’s New Officers. ACA Prior Conventions. The Cryptogram: Sample Issue.

Answers to Questions (FAQ)

How to encrypt using Letter-to-Number/A1Z26 cipher?

Substitution Cipher Solver Tool

A1Z26 encryption requires to count the positions/ranks of letters in the alphabet. If it is the Latin alphabet of 26 characters here is the correspondence table letter ↔ number/value:

Replace each letter with its position in the alphabet (A = 1, B = 2, ... Z = 26)

Example:DCODE is encrypted 4-3-15-4-5 by alphanumeric substitution

Often the space character is also encoded with the number 0

How to decrypt Number-to-Letter cipher?

Decryption requires taking each number and replace it with the letter of same position in the alphabet: 1 = A, 2 = B, ... 26 = Z

Example:1.12.16.8.1.2.5.20 gives ALPHABET

How to recognize Letter-to-Number ciphertext?

The crypted message is made of numbers between 1 and 26, sometimes the number 0 is used to code a space.

The digit 5 for E is supposed to appear regularly for an english text.

This encryption is sometimes called alphanumeric code.

What are the variants of the Letter-to-Number cipher?

Shift of numbers: the alphabet can start with A = 0 or A = 1, but also A = 65 or A = 97 (ASCII code).

Use of a supplementary character for space (usually 0 or 27)

Use of leading zeros to be able to concatenate numbers AB = 0102, else AB = 12 and 12 = L.

Use of a custom alphabet, or reversed alphabet (A=26, Z=1)

Use of modulo 26 in order to get 1=A,2=B,...26=Z then 27=A, 28=B etc.

Cipher Solver Tools

Source code

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NB: for encrypted messages, test our automatic cipher identifier!

Questions / Comments

This simple tool allows you to encode and decode messages with a simple substitution cipher. For a cipher breaker, see Substitution cipher breaker. You can read a cipher description and some considerations regarding the strength of a cipher below the calculator.

Cipher Solving Tools

Substitution Cipher Solver Tool

According to Wikipedia, in cryptography, a substitution cipher is a method of encrypting by which units of plaintext are replaced with ciphertext, according to a fixed system; the 'units' may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing the inverse substitution.

A simple substitution is the substitution of single letters separately. The substitution key is usually represented by writing out the alphabet in some order. The Caesar cipher is a form of a simple substitution cipher. For example, its ROT2 key can be presented as CDEFGHIJKLMNOPQRSTUVWXYZAB. This means that A is replaced with C, B with D, and so on.

The number of all possible keys for a simple substitution cipher is a factorial of 26 (26!). However, you can break it if you have enough ciphered text by using frequency analysis or the stochastic optimization algorithm (check out our Substitution cipher breaker). The cipher does not change language letter frequencies (it is said to be monoalphabetic), unlike, for example, the polyalphabetic Vigenère cipher, so it is considered to be rather weak.

Paste text into the field, fill the key, choose 'encode' if you have pasted clear text or 'decode' if you have pasted ciphered text, and press 'Calculate'. Traditionally, punctuation and spaces are removed to disguise word boundaries and text is written in blocks of letters, usually five. This option is supported for encoding as well.