OTA 2.0: An Advanced and Secure Blockchain Steganography Algorithm

Abstract

Blockchain technology, a disruptive force beyond Bitcoin, is finding applications across
various fields, including scientific disciplines like steganography – the art of data hiding.
Digital steganography has gained momentum with data digitization, especially in
multimedia environments like images, text, audio, and videos. Blockchain's integration
into steganography has led to interesting developments, like the OTA (OzyavasTakaoglu-Ajlouni) algorithm introduced in 2021. The OTA algorithm consists of two
stages: the OTA-steganography algorithm and the OTA-chain algorithm (private
blockchain). Developed using Java and JavaScript, the OTA platform utilises OTA-coins
as its native currency. Previous versions allowed various file types as cover-multimedia,
with the secret message encrypted using the Vernam Cipher symmetric encryption and
hidden using OTA steganography. Unlike other steganography methods, OTA doesn't
alter the cover-multimedia but uses bit-level data marking. In the OTA system, the
marked data indices are stored in 1 KB arrays and transmitted to the receiver as
transactions via OTA-chain, each incurring a fixed fee of 1 OTA-coin to prevent DDoS
attacks. The OTA 2.0 algorithm improved on the previous version by switching to
Hyperledger Fabric protocol, which offers open-source, permissioned blockchain
solutions, decentralisation capabilities, and self-sovereign identity support. The new
version also enhanced block creation time to 2 seconds, increased block size to 90 MB,
and employed a 4-bit marking pattern while eliminating transaction fees. Thanks to its
innovative key-sharing method and permissioned architecture, OTA 2.0 proves resistant
to steganalysis methods commonly used in steganography studies.