Monoalphabetic

The Patristic Cipher, also known as a Patristocrat, is a form of monoalphabetic substitution cipher specifically designed to conceal word boundaries and sentence structure. Unlike a standard substitution cipher where spaces are preserved, the Patristic Cipher removes all spaces and punctuation from the plaintext and then regroups the resulting ciphertext into uniform blocks, traditionally of five letters. This visual flattening makes frequency analysis more difficult and forces the solver to reconstruct word breaks mentally.

The Keyed Caesar cipher is a variation of the classical Caesar cipher, adapted to increase security by combining a keyword with a shift-based substitution. The original Caesar cipher, attributed to Julius Caesar around 58–50 BCE, shifts each letter of the alphabet by a fixed number of positions. In the Keyed Caesar cipher, a keyword is first used to create a modified alphabet: the letters of the keyword are placed at the start of the alphabet (omitting duplicates), followed by the remaining unused letters in standard order.

The Kama-Sutra cipher, also known as the Kamasutra cipher, is a classical substitution cipher originating in ancient India and described in the Kama Sutra, traditionally attributed to Vātsyāyana around 300 CE to 400 CE. Despite its modern name association, the cipher itself is not related to sexuality; it appears in a section on secret writing as a practical method for discreet communication. The cipher is a simple monoalphabetic substitution system based on paired letters rather than a full substitution table.

The Simple Substitution cipher is one of the oldest and most straightforward encryption methods, where each letter of the plaintext is replaced with a unique corresponding letter or symbol from a fixed ciphertext alphabet. Its origins trace back to classical antiquity, with early examples appearing in the works of Julius Caesar around 58–50 BCE for basic shift substitution, and more formalized systems appearing in Europe during the Renaissance.