K-Gate Lock: Multi-Key Logic Locking Using Input Encoding

This repository contains resources related to K-Gate Lock logic locking scheme.
Kevin Lopez & Amin Rezaei

File Structure

The file structure is organized as follows:

• Tools - Tools used to test the algorithm:

  • RANE - Tool used to perform attacks on encrypted circuits.
  • NEOS - Tool used to perform attacks on encrypted circuits.
  • ABC - Tool used to convert Verilog, BLIF, and BENCH files.

• src - The source code for encrypting and testing the algorithm:

  • test_runs - Contains the previously run algorithms. The folder name matches the configuration run.
    • Example: k_2____MaxGates_10____5bits locked 10 gates with level 2 and 5-bit key size.
  • PowerMeasurement - The Xilinx Vivado project used for power measurement.
  • help_scripts - Contains scripts to convert BLIF and Verilog files using abc.
  • Other Files - Used for the implementation of the algorithm.

Understanding the Algorithm

The K-Gate Lock logic locking scheme secures digital circuits by adding gates that require specific keys to function. The process is illustrated below:

1. Original Circuit: Get the inputs from the user on how to lock the circuit.
   • Identify the circuit to be locked.
   • k to lock, g to lock
   • keys required.
2. Gate Selection: The algorithm selects gates to lock based on the given k.
3. Key Integration: Generate the truth table and assign key inputs to achieve the desired input combination. Use K-maps to simplify boolean expressions.
4. Encryption: Integrate the locked gates into the original circuit, making the circuit dependent on the keys for correct functionality.

For a deeper explanation, refer to the paper.

Running the Algorithm

Before running any help script, ensure the following steps are completed:

1. Install Dependencies:

   • Using Linux, install the following tools:
     • NEOS
     • Yosys
     • ABC
     • RANE
   • Additionally, install Python and PyEDA.

2. Navigate to the src Folder:

   • Run the following command to navigate inside the src folder:

     cd <project_dir>/src/

Encrypting a BENCH File

To encrypt a BENCH file, simply run the main.py file with a file to encrypt, keys, and k (NOTE: python, PyEda need to be installed)

• python3 main.py "./src/benchmarks/iscas85/c17.bench" --key_values="3 4 5" --k=2

Testing Algorithm

To test the algorithm in a single file, run the test_bench_file.sh using Linux ( NOTE: NEOS, python, and PyEda need to be installed)

• ./test_bench_file.sh ./benchmarks/iscas85/c17.bench --keys="3 4 5" --k=2

This command will generate the encrypted file (run the python script motioned in 'Encrypting a BENCH file'), then run NEOS with SAT solver.

Testing a Whole Folder

to perform a batch test, run the ./test_folder.sh file with the following positional

• Folder path: Where are the files located
• keys: keys to test with example "3 4 5"
  • Key1 = 3 or 011
  • Key2 = 4 or 001
  • Key3 = 5 or 101
• k: number of inputs that the locked gate needs to have

Example of a command:

• ./test_folder.sh ./benchmarks/iscas85 "5 5 5" 2

Citation

@INPROCEEDINGS{KGL,
  author={Lopez, Kevin and Rezaei, Amin},
  booktitle={Proceedings of 30th Asia and South Pacific Design Automation Conference (ASP-DAC)}, 
  title={K-Gate Lock: Multi-Key Logic Locking Using Input Encoding Against Oracle-Guided Attacks}, 
  year={2025},
  volume={},
  number={},
  pages={794-800},
  doi={10.1145/3658617.3697764}
  }

License

This project is licensed under the MIT License - see the LICENSE file for details.