Transposition

The Pinprick Cipher is a simple symbolic substitution cipher in which letters are represented by patterns of dots (·) and circles (o). It works by assigning a unique sequence of these symbols to each letter, making it easy to encode short messages while hiding them in plain sight. Its origin is somewhat obscure, but it was historically used for secretive or playful communications, often in correspondence or small notes.

The Null Cipher is a steganographic technique that hides a secret message within an ordinary-looking text. Most letters in the text are "nulls" and do not convey information, while only certain letters—determined by a prearranged rule—carry the hidden message. Its security relies on subtlety: without knowledge of the extraction rule, the cover text appears completely normal.

The Grid Transposition Cipher is a classical transposition cipher that arranges plaintext letters into a rectangular grid and then reads the letters off according to a specific pattern, such as by columns, rows, or a predefined route. Unlike simple substitution ciphers like the Simple Substitution Cipher, the Grid Transposition Cipher does not alter the letters themselves, but instead reorders them, making frequency analysis of single letters ineffective.

The Combination Cipher is not a single fixed algorithm but a method that deliberately combines two or more classical ciphers into a layered encryption process. By applying multiple techniques in sequence — typically a substitution followed by a transposition — the resulting ciphertext becomes significantly harder to analyze than either method alone.

The Columnar Cipher is a classical transposition cipher that rearranges the letters of a plaintext message into columns and then reads them out in a permuted order according to a keyword. Unlike substitution ciphers, it obscures the message by reordering letters without changing them.