Luminescent CsPbCl₃ (CPC) perovskites nanocrystals (NCs) hold strong potential for applications in the display and information encryption. However, their static monochromatic luminescence (blue-emission) and limited photostability (thermal quenching) result in relatively low photoluminescence quantum yield (PL QY). Herein, we introduce a facile and controllable quasi-solid-state cation exchange strategy, in the presence of KCl salts, to synthesize highly luminescent Mn-doped CPC NCs (Mn/KCl-CPC NCs for short). These halide perovskites can be achieved through fast and controllable cation exchange (within 20 min) reactions, exhibiting extraordinary optical properties, including high PL QY of 43 ± 5 % and the anti-thermal quenching temperature up to 423 K. The density functional theory calculations reveal that the extra Cl− ions from KCl salts can not only extend Pb-Cl bond lengths of CPC NCs, but also act as an intermediate energy level between conduction band edge of host CPC NCs and Mn²⁺-dopant energy level, thus enhancing energy transfer from host to Mn²⁺ centers. Particularly, Mn/KCl-CPC NCs display temperature-dependent and time-valve controllable components-dependent luminescence. Upon thermal or photic stimulations, high-security multilevel anti-counterfeiting application based on cation (Mn) and anion exchange in CsPbX₃ NCs is demonstrated (including nearly full-color coverage). This facile and simply post-treatment technique can both increase the PL QY and photo-/chemical- stability of CPC NCs and expand their applications in dynamic luminescent anti-counterfeiting without using modulated UV light or other X-ray/excitation wavelength-dependent light sources.