CREST

The Coalition/Ringleaders Encryption and Steganography Toolkit, more commonly known by its abbreviation CREST (/kɹɛst/), formerly the Coalition Encryption and Steganography Toolkit or CEST (/sɛst/) is a series of standards and tools used by the Coalition, Ringleaders and a small handful of other mages and demi-humans in the Greater Offetstine Area to facilitate encrypted conversation.

The core of CREST is the Circle symmetric block cipher, a variable-cost Feistel cipher designed and implemented by human computer scientist Serena Markov to operate on blocks ranging from 64 to 512 bits. The reference implementation of Circle is often known by its library name as it was deployed, libcrest. In addition to Circle, CREST uses various well-known hash and signature functions to offer a full cryptographic suite.

History

The Circle block cipher was initially developed by computer scientist and outspoken cryptography enthusiast Serena Markov in 1988, when she was hired by King's Court Law to develop an encryption toolkit under the pretense of facilitating sensitive communications involving client affairs between King's Court and other legal firms of the time. She was hired during a time when standards such as encrypted email were still in their infancy. She was to be supervised by another member of the Coalition under the guise of a peer, and joined by another amateur cryptographer, although she was set to lead the effort.

Markov, having prior experience developing an end-to-end cryptography solution with her earlier "Secret Cypher" program for early 8-bit home computers, agreed under the condition that her software, then called libcircle, would be released as free and open-source. Over time, Markov began to grow suspicious about her clients, and tensions flared between the two. While members of the Coalition that had contracted her were interested primarily in using the software for private communication, and developed a custom frontend and steganography toolset based on libcircle.

Upon discovering the true application of her code, and after a verbal altercation with her clients, Markov quit the team hired to develop Circle, eliciting the ire of her Coalition supervisor. She was later targeted by the Coalition as a human dissident, and a bounty was placed on her head. Eventually, she was turned into a vampire and inflicted with amnesia, upon which she assumed the identity of Modeste Daniau. Development of libcircle continued, and the software and details of the algorithm remained proprietary.

As the Coalition eventually fell, members of the Ringleaders adapted libcircle and the CEST frontend for their own use from leaked source code, releasing their fork under the titles of libcrest and CREST. The software remains maintained to date, although as availability of encryption to the general public grows, it is expected that libcrest will eventually be deprecated, and CREST will use modern encryption algorithms along with its own in-house steganography as time goes on.

Real life

The Circle block cipher is roughly inspired by corresponding real-life block ciphers such as DES and AES/Rijndael.

CREST and libcircle fill an analogous role to software packages such as OpenSSL and GnuPG in the real world.