Inside Windows Product Activation

Hardware Information

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

Bit-fields

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.

double word	offset	length	bit-field value based on
H1	0	10	volume serial number string of system volume
H1	10	10	network adapter MAC address string
H1	20	7	CD-ROM drive hardware identification string
H1	27	5	graphics adapter hardware identification string
H2	0	3	unused, set to 001
H2	3	6	CPU serial number string
H2	9	7	harddrive hardware identification string
H2	16	5	SCSI host adapter hardware identification string
H2	21	4	IDE controller hardware identification string
H2	25	3	processor model string
H2	28	3	RAM size
H2	31	1	1 = dockable, 0 = not dockable

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.