Tool to decrypt/encrypt with input mode Multi-tap (or ABC code or Tap mode) used in mobile phones to type text/SMS on a keyboard with a numeric keypad.
Multi-tap Phone (SMS) - dCode
Tag(s) : Telecom, Polygrammic Cipher
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Multi-tap Phone (SMS)
Multi-tap Decoder/Translator
T9 vs Multitap Confusion
Multitap ABC should not be confused with T9 predictive text. 'DCODE' is written '3222666333' in Multitap and '32633' in T9.
Multi-tap Encoder/Translator
Answers to Questions (FAQ)
What is the Multitap code? (Definition)
The multi-tap code is the name given to the historic technique of writing SMS on the first mobile phones with a keyboard of 10-12 numeric keys.
How to encrypt using Multitap cipher?
Multitap replaces a letter by repeated digits defined by the corresponding key code on a mobile phone keypad (This mode is used when writing SMS/Texto).
The correspondence table is:
| A | 2 | B | 22 |
|---|---|---|---|
| C | 222 | D | 3 |
| E | 33 | F | 333 |
| G | 4 | H | 44 |
| I | 444 | J | 5 |
| K | 55 | L | 555 |
| M | 6 | N | 66 |
| O | 666 | P | 7 |
| Q | 77 | R | 777 |
| S | 7777 | T | 8 |
| U | 88 | V | 888 |
| W | 9 | X | 99 |
| Y | 999 | Z | 9999 |
Example: DCODE becomes 3222666333
This standard also has the name of E.161 created by the ITU Telecommunication Standardization Sector (ITU-T). It only sets letters from A to Z, other characters such as digits or lowercase uppercase distinctions are not normalized.
How to decrypt Multitap cipher?
Multi-tap decryption consists in replacing groups of numbers by their corresponding letter, but if there is no separator, then it is necessary to test all the possibilities of words and only return the existing words in the dictionary.
Example: 2222 = AAAA or AAB or ABA or AC or BAA or BB or CA
How to recognize Multitap ciphertext?
The ciphered message is made of numbers with digits often repeated consecutively, between 1 and 3 times, there are few (or none) 1 or 0.
With new smartphones, this mode has become obsolete and is often used as a simplistic cipher.
Any references to old telephones (Nokia, Bi-Bop, etc.) and keypads (beep) are clues.
What are the variants of the Multi-tap cipher?
Variations of the multi-tap ABC can be created by varying the writing.
Example: A code such as 222 can be written 2*3, 2^3 or 23.
An over-encryption is possible by coding a message twice
Example: PHONE = 7446666633 = PGGMMMMMDD
Mobile phones have other typing techniques, such as T9 predictive text.
When Multi-tap was invented?
The first patent is from 1985. It has since been used in the majority of mobile phones keypad, had its heyday with the Nokia, and then disappeared with touch screens and smartphones type iphone.
Source code
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Multi-tap Phone (SMS) on dCode.fr [online website], retrieved on 2023-10-01,
