| US 7,519,823 B1 | ||
| Concealed, non-intrusive watermarks for configuration bitstreams | ||
| Paul R. Schumacher, Berthoud, Colo. (US); Robert D. Turney, Watertown, Wis. (US); Mark Paluszkiewicz, Schaumburg, Ill. (US); Prasanna Sundararajan, Mountain View, Calif. (US); and Brandon J. Blodget, Santa Clara, Calif. (US) | ||
| Assigned to XILINX, Inc., San Jose, Calif. (US) | ||
| Filed on Aug. 12, 2004, as Appl. No. 10/917,042. | ||
| Int. Cl. H04L 9/00 (2006.01) | ||
| U.S. Cl. 713—176 [713/1; 713/2; 713/100; 713/168; 713/189; 380/268; 716/16; 716/17; 716/18] | 19 Claims |
| 1. A method for embedding identifier information in a configuration bitstream for a programmable logic device (PLD), wherein
the configuration bitstream implements a design, comprising:
providing for determining bits in a configuration bitstream that are unused in implementing the design on a PLD, wherein the
bits are unused bits;
wherein the providing for determining the unused bits includes using a configuration bit definition in determining whether
a bit is essential or unused, and the configuration bit definition is a configuration bit description equation;
providing for encrypting the identifier information;
providing for selecting a subset of the unused bits using a function; and
providing for placing the encrypted identifier information in the selected subset of unused bits,
wherein the providing for selecting a subset of the unused bits includes initializing a random number generator with a seed,
generating a pseudo-random sequence of bits by the random number generator, and selecting the subset of bits using the pseudo-random
sequence of bits.
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