Inside Windows Product Activation

As discussed above, the hardware configuration linked to the Installation ID is represented by the two double words H1 and H2.

For this purpose, the double words are divided into twelve bit-fields. The relationship between the computer hardware and the bit-fields is given in the following table.

Bit 31 of H2 specifies, whether the bit-fields represent a notebook computer that supports a docking station. If docking is possible, the activation mechanism will be more tolerant with respect to future hardware modifications. Here, the idea is that plugging a notebook into its docking station possibly results in changes to its hardware configuration, e.g. a SCSI host adapter built into the docking station may become available.

Bits 2 through 0 of H2 are unused and always set to 001.

If the hardware component corresponding to one of the remaining ten bit-fields is present, the respective bit-field contains a non-zero value describing the component. A value of zero marks the hardware component as not present.

All hardware components are identified by a hardware identification string obtained from the registry. Hashing this string provides the value for the corresponding bit-field.