OpenCL is the framework that hashcat uses to perform the computation on the selected hardware.
Without an OpenCL driver for a given hardware platform, you cannot use modern hashcat on that hardware. If you want to use hashcat on your CPUs, you need an OpenCL driver for that CPU family (Intel, AMD). If you want to use hashcat on a GPU, you need an OpenCL driver for that GPU family (NVIDIA, AMD).
Without an OpenCL driver for a given hardware platform, you cannot use modern hashcat on that hardware. If you want to use hashcat on your CPUs, you need an OpenCL driver for that CPU family (Intel, AMD). If you want to use hashcat on a GPU, you need an OpenCL driver for that GPU family (NVIDIA, AMD).
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