Delastelle's fractionated transposition cipher with Polybius coordinates.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Invented by Félix Delastelle around 1901, it was one of the first classical ciphers to achieve fractionation—breaking letters into separate coordinates and transposing them across periods before recombining.
The period controls how many letters are grouped together for coordinate transposition. Larger periods increase diffusion of letter frequencies.
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