Format-Preserving Tokenization Pipeline (2D)

Smart-data records — account numbers, smart-meter IDs, telemetry keys — stream through a 2D pipeline where each 8-digit value is split into a left and right half and pushed through a Feistel network, one round-function gate at a time. This companion to the 3D pipeline computes the identical Feistel math independently and adds a dedicated round-by-round diffusion trace beneath the live view, plus a draggable pipeline you can scrub without stopping the stream. Switch between reversible Format-Preserving Encryption, which any holder of the round key can run backward to recover the exact original digits, and one-way hash tokenization, which a vault alone can reverse — then try detokenizing the last completed record with the correct key and with a guessed wrong one to see why key secrecy is the entire security model.