• Making a good watermark involves:
• Keeping the correct FUNCTIONALITY of the IP
• The overhead introduced by the watermark must be negligible or very small
• Demonstration with high credibility of the IP manufacturer or the probability of ip
repetition is very small
• Easily detecting it
• It is difficult or even impossible to remove
• Its addition and detection must be transparent to existing design tools
• Protecting a specific part of the project
• Unpredictable design overhead
• Random constraints based on the watermark
• Non-deterministic design tools and software
• Controllability vs security
• Zero-overhead watermark
• Normal design to achieve optimal performance
• Identifying where we can include the watermark without causing performance
degradation
• Inclusion of watermark
• Partial or total redesign
• Zero-overhead watermark in FPGA
• Reading the circuit code
• Circuit synthesis
• Place & Route
• Get information about delays in the circuit
• Change the constraints about delay for n selected wires (n represents the number of bits of
signature)
• Place & Route
• There are fulfilled constraints for running time ?
• If not, we will return to modify the constraints by reselect the wires or we will reduce the
dimension of the signature
• Generate bitstream ??????
Source FF Destination FF Original delay Watermark Delay
Inst_reg_0 Aluinp1_reg_3 17.758 0 17.750
Inst_reg_6 Aluinp1_reg_3 17.755 1 17.751
Inst_reg_1 Aluinp1_reg_3 17.733 0 17.730
Inst_reg_3 Aluinp1_reg_3 17.651 0 17.650
Inst_reg_6 Aluinp1_reg_1 17.374 1 17.371
Inst_reg_1 Aluinp1_reg_1 17.352 1 17.351
Inst_reg_5 Aluinp1_reg_3 17.312 0 17.310
Inst_reg_0 Aluinp1_reg_5 17.066 1 17.061
Proiectare în FPGA Original Watermark Distanța Hamming
DAP Resources 1011 1011 1.09%
f = 40 MHz Yes Yes
Video Resources 961 961 4.39%
f = 40 MHz yes Yes
RISC Resources 410 410 2.52%
f = 50 MHz Yes Yes
ADDRGEN Resources 174 174 2.41%
f = 50 MHz Yes yes
Detectability of watermark
How to discover the embedded watermark and prove authorship ?
Fingerprinting
• Watermark cannot distinguish between different copies of the same IP (different IPs).
• If we sell the IP to 10 users, we will want to know which IP is assigned to whom
• Digital fingerprint is a protocol that make every copy of an object unique and
distinguishable.
• Fingerprint = multiple distinct watermarks
• The technique addresses 2 problems: how do we generate IPs with different fingerprints
and how to distribute solutions to users
Fingerprinting
• Phase 1 – IP generation
• Quantity - how he could create a large lot of solutions
• Quality - assumes that the solutions found keep the values of the IPs
• Run-time - how we minimize time and complexity to generate as many solutions as
possible.
• Phase 2 – IP distribution
• Uniqueness - different users must receive unique fingerprint IPs
• Robustness - modifying or removing fingerprints from IPs should be impossible or as
difficult as possible to achieve by a hacker.
• Collation - fingerprint IPs should be as different as possible from each other in order
to avoid collations
Tehnici Fingerprinting
Metoda 1 – adăugarea de constrângeri Metoda 2 - iterativă
Tehnici Fingerprinting
Metoda 1 – adăugarea de constrângeri Metoda 2 - iterativă
Exemplu de colorare a grafului
Exemplul 2
Metoda duplicării
• Puteam crea mai multe soluții prin modificarea culorii sau
specificarea nodurilor fără a mai verifica nodurile adiacente sau
vecinii.
Fingerprint: condiții don’t cares
Fingerprint: condiții don’t cares
Hardware metering
• Companies that design circuits can not afford to assume the costs of producing them
• Manufacture of designed circuits – outsourcing
• Outsourcing companies have access to all the details of the circuit and the possibility to produce more chips than were
ordered
• ‘’ Integrated circuits metering, or hardware metering, is an effective method to defend against this IP infringement.
Integrated circuit metering is a set of security protocols that enable the design house to achieve post-fabrication control
over their Ics’ – F. Koushanfar
• Once the IP is made and the circuit mask is built, the company that designed the circuit no longer has any control over the
circuit
• The chip company can use all the information in its possession as well as the production facilities to reproduce the design
with negligible costs.
• Can we use digital watermarking ?
Hardware metering
• Using a unique tag for each circuit built and controlling them
• Chip identification – passive metering (enable, disable or control
the chip)
• Metering methods can be controlled internally or externally
depending on how the control is – part of the design or not
• Using serial numbers
• A serial number can be inscribed on the circuit or can remain
permanently in a memory
• The ICID tag was proposed in 2007 and is considered non-
clonable because it is based on the variation of silicone
production
