RESEARCH · OPEN ACCESS
Verifiable one-way file transfer across air gaps
A preprint describing how Kionel works and what we measured: the protocols, their formal analysis, the coding that lets printed pages survive lost codes, and the limits.
Taha Bayar, Lumina Digitale · ORCID 0009-0009-6247-4985
Preprint, 30 September 2026 · Zenodo · CC BY 4.0
DOI: 10.5281/zenodo.23064776
What it covers
- Formal analysis. The two-way handshake and the two one-way modes are modelled in ProVerif; secrecy, authentication and receipt soundness hold under stated assumptions, and variants that drop an assumption produce the expected attacks.
- Printed pages. Spare codes chosen so that each covers a third of the file, plus Gaussian elimination when the decoder stalls: a 30 KB file with 8 of its 48 codes missing came back in 91% of 300 trials, against 3% with ordinary spares.
- Live camera reading. Decoding only the region around the last code cut a 200 KB transfer from 35 to 27 seconds on a processor slowed to phone speed.
- Limits. Phone figures come from one device and synthetic benchmarks; there has been no independent security audit.
How to cite
Bayar, T. (2026). Verifiable one-way file transfer across air gaps with screens, paper and serial cables. Preprint. Zenodo. https://doi.org/10.5281/zenodo.23064776