T9 AKA Phone Code
In the T9 system, each digit key on the phone keypad corresponds to a set of letters. By pressing the keys multiple times, you cycle through the letters associated with each key. The mapping of letters to the keypad digits is based on the arrangement of letters on a standard telephone keypad:
Nihilist Cipher
The Nihilist Cipher is a classical cipher combining fractionation and polyalphabetic substitution, invented by the Russian-Jewish revolutionary and cryptographer F. K. Nihilist in the 1880s. It gained practical notoriety among Russian revolutionary groups for clandestine communication. The cipher operates by first converting plaintext letters into numbers using a Polybius square, then adding a numeric key sequence to these numbers to create the ciphertext.
Letter Number Substitution
The Letter Number Substitution cipher is a classical substitution method in which each letter of the alphabet is replaced by a corresponding number. Its origins are difficult to trace precisely, as variations of letter-to-number mapping have existed since ancient times, but it became widely referenced in cryptographic manuals during the 19th century for educational and puzzle purposes. The method provides a simple way to transform text into a numeric sequence while remaining reversible, making it suitable for manual encryption and early secret messaging.
Knapsack Cipher
The Knapsack cipher, also known as the Merkle–Hellman knapsack cryptosystem, is an early public-key cryptosystem introduced by Ralph Merkle and Martin Hellman in 1978. It is based on the subset-sum problem, where the goal is to select numbers from a set that sum to a target value. The cipher uses a private superincreasing sequence, then applies a multiplier m and a modulus n to produce a public key.
Rout Cipher
The Rout Cipher is a type of transposition cipher used to encrypt messages by rearranging the characters according to a specific pattern or route. It is a historical encryption method that predates modern cryptographic techniques and offers a basic level of security.
In the Rout Cipher, the plaintext is written into a grid or matrix row by row, following a predetermined route specified by the encryption key. The route could be a zigzag pattern, a winding path, or any agreed-upon sequence.
ROT Cipher
The ROT Cipher, also known as the Caesar Cipher or Caesar Shift, is one of the simplest and earliest known encryption techniques used for encoding messages. It is named after Julius Caesar, the Roman military leader who reportedly used this method to protect confidential communications during his time.
Pinprick Cipher
The Pinprick Cipher is a basic and straightforward form of secret writing, often used for encoding messages in a discreet manner. It involves using a pin or a sharp tool to create small holes or dots on a piece of paper in a specific pattern to represent letters, numbers, or symbols.
To use the Pinprick Cipher, each letter, digit, or symbol in the plaintext is assigned a unique pattern of holes or dots. The pattern could be based on a predefined code, a secret key, or any agreed-upon method between the sender and recipient.
Null Cipher
The Null Cipher, also known as the Null Encryption or Null Message, is a simplistic cryptographic technique where specific letters or symbols are deliberately left blank or null in a message. Instead of using complex algorithms or substitutions, the Null Cipher relies on the absence of characters to convey hidden information.
Gronsfeld Cipher
The Gronsfeld Cipher is a variation of the Vigenère cipher, attributed to the German mathematician Johann Gronsfeld, who introduced it in 1863. It was primarily developed as a method for encrypting messages using a numeric key, making it a simpler form of the more complex Vigenère cipher.
Dice Cipher
A Dice Cipher, also known as a Dice Cryptography or a Book Cipher, is a cryptographic technique that uses dice as a randomization tool to generate a series of numbers that correspond to words or characters in a pre-selected reference book. It is a form of polyalphabetic substitution cipher.
Here's a general overview of how a Dice Cipher works: