Data　security　is　a　major　concern　in　digital　age,　which　generally　relies　on　algorithm-based　mathematical　encryption.　Recently,　encryption　techniques　based　on　physical　principles　are　emerging　and　being　developed,　leading　to　the　new　generation　of　encryption　moving　from　mathematics　to　the　intersection　of　mathematics　and　physics.　Here,　device-level　encryption　with　ideal　security　is　ingeniously　achieved　using　modulation　of　the　electron–hole　radiative　recombination　in　a　GaN-light-emitting　diode　(LED).　When　a　nano-LED　is　driven　in　the　non-carrier　injection　mode,　the　oscillation　of　confined　electrons　can　split　what　should　be　a　single　light　pulse　into　multiple　pulses.　The　morphology　(amplitude,　shape,　and　pulse　number)　of　those　history-dependent　multiple　pulses　that　act　as　carriers　for　transmitted　digital　information　depends　highly　on　the　parameters　of　the　driving　signals,　which　makes　those　signals　mathematically　uncrackable　and　can　increase　the　volume　and　security　of　transmitted　information.　Moreover,　a　hardware　and　software　platform　are　designed　to　demonstrate　the　encrypted　data　transmission　based　on　the　device-level　encryption　method,　enabling　recognition　of　the　entire　ASCII　code　table.　The　device-level　encryption　based　on　splitting　electroluminescence　provides　an　encryption　method　during　the　conversion　process　of　digital　signals　to　optical　signals　and　can　improve　the　security　of　LED-based　communication.　©　2023　Wiley-VCH　GmbH.