A Secure Closed-Group Communication Platform for Defence Personnel Using Blockchain Identity and Covert Messaging

Defence personnel have high-security communication systems which are subject to metadata leakage, centralized identity attacks and unauthorized data copying. Although the current systems include end-to-end encryption in the transmission of the message, they do not have the feature of decentralized verification of identity, covert communication, geospatial access control, and protection of data after delivery. In order to overcome these difficulties, this paper offers a proposal of a Secure Closed Group Communication Platform to Defence Personnel and Authorised Family Members. The proposed system will combine decentralized identity validation based on Ethereum wallet addresses on a personal blockchain setup (Ganache), AES-256 GCM message confidentiality, and Least Significant Bit (LSB) image steganography to communicate the message in disguise. Furthermore, a message decryption mechanism is geospatially limited and uses the Haversine algorithm where confidential information is only decrypted when within an authorized geographic area. An ephemerality option to burn-on-read also improves the security level since messages are automatically deleted within a given time. The Android and Windows platform experimental analysis illustrates that authentication is very reliable, steganographic embedding is efficient with PSNR values of over 40 dB and geofencing performance is very accurate with a spatial resolution of up to 10 meters. The findings suggest that the given architecture can offer a multi-layered secure communication model that is capable of enhancing confidentiality, identity verification, and contextual data protection as a part of defence-focused communication systems

Confidentiality · Covert · Covert channel · Encryption · Information hiding · Metadata · Steganography · Chaos-based Image/Signal Encryption · Cryptography and Data Security · Security in Wireless Sensor Networks