Patent ID: 7752446

Claim:
A general purpose computer for watermarking a data repository having tuples, each tuple being associated with one or more attributes, each attribute having one or more bit positions, at least some bit positions having a bit value, the computer comprising: a hardware processor that: establishes watermark values for at least one bit position for at least one attribute of at least some of the tuples based on private information, to establish a watermark, wherein at least one of: tuples to be marked, or an attribute to be marked within a tuple, are determined based on the private information, wherein a tuple is tested for marking using the private information and if it is to be marked; determines which attribute(s) of the tuple to mark; for attributes determined to be marked, determines which bit(s) of the attribute to mark; determines a marking value for bits of an attribute selected for marking; and changes a value of a bit of an attribute to be marked to the marking value.