ARC4 DMR Key Finder: is a research, service, and interoperability utility intended for authorized work with Motorola, Hytera, and Anytone DMR radios that use DMRA EP / ARC4-40 privacy. It is designed for use only on radios you own in a controlled test lab and can help identify the active key, verify legacy configurations, confirm correct radio setup, and support analysis of older protected traffic in maintenance or archive recovery scenarios. The software is useful for technicians, collectors, engineers, and lab users who need to evaluate how specific DMR devices and firmware builds implement legacy 40-bit privacy, compare behavior across models, and document the limitations of older protection methods before planning migration to stronger modern encryption. Near the end of a support or validation workflow, it is also important to note that these are compiled files for Raspberry Pi 1/2/3/4 only, provided without source code, and they will not run as is on other hardware or operating systems without separate porting or adaptation. Use of this software on radios that do not belong to you may be illegal in many countries, so you must check and follow your local laws before use.