This document discusses cyber security for GPRS terminals used in fiscal devices like cash registers and printers that send financial data to tax authorities. It proposes using blockchain technology to encrypt the data transmitted from these devices via GPRS terminals to increase security. Currently, most fiscal devices transmit plaintext data without encryption via GPRS terminals. The document surveys previous generations of fiscal devices and their vulnerabilities. It suggests an improved design for new or existing fiscal devices that incorporates an internal device like GPRS to transmit encrypted data directly to tax authority servers without additional services. This would help address security issues with the current systems.