Cute-Lock: Behavioral and Structural Multi-Key Logic Locking Using Time Base Keys

This repository contains resources related to Cute-Lock logic locking family.
Kevin Lopez & Amin Rezaei

Prerequisites

• Ubuntu 22.04 (WSL, VM, or native installation)
• Python 3
• Conda

Setup

1. Install Python 3

2. Set up the Python environment using Conda:

   conda env create -f /src/environment.yml
   conda activate dynamic_key_logic_key_locking
   

3. Install the following tools (found under src/Tools/*):

   • yosys
   • abc
   • neos
   • RANE
   • HALL

   Download and compile these repositories from GitHub. Additional dependencies may be required.

4. Navigate to the 'src' folder.

Cute-Lock-Beh

Encrypting a File

To encrypt a file using the Behavioral Multi-Key Locking algorithm, use the Python script with the following arguments:

python CreateEncryption.py [arguments]

Arguments:

• --file_name: Path to the Verilog file to encrypt. Default: "./nonKey.v"
• --keys: Keys to use for encryption (space-separated). Default: "1 2 3 4"
• --counter_cycles: Number of clock cycles per stage. Default: 2
• --output_dir: Output directory for the encrypted file. Default: "./"

Example:

python CreateEncryption.py --file_name path/to/your/file.v --keys 5 6 7 8 --counter_cycles 3 --output_dir path/to/output/

If an argument is not specified, the script will use its default value.

Automated File Encryption

This process starts with a seq.v file (regular sequential file) and creates a locked_seq_file.v file.

Single Test

Run the run_file_encryption.sh script with a seq.v file:

./run_file_encryption.sh seq.v

Example:

./run_file_encryption.sh NonKey.v

Multiple Tests

To run tests on multiple files in a directory:

./run_multiple_file_encryption.sh dir/path

Example:

./run_multiple_file_encryption.sh ./FSMs/

Script Process

The script performs the following steps:

1. Encrypts the seq.v file using the multi-key locking algorithm.
2. Creates .blif files of both seq.v and the encrypted file using yosys.
3. Modifies the .blif files:
   • Replaces .subckt with .names
   • Adjusts .latch syntax
   • Ensures at least one state (preferably the first state, s1) is 0
4. Creates .bench files from the .blif files using abc.
5. Tests the locking algorithm by running the .bench files using neos.

Cute-Lock-Str

This process starts with a seq.bench file and creates a locked_seq_file.bench file.

Encrypting a .bench File

Use the /src/structuralEncryptor.py script with the following options:

• --file_name: (Required) Path to the file to encrypt. Default: ./s27.bench
• --keys: (Optional) Space-separated string of keys for encryption. Default: "2 2"
• --output_dir: (Optional) Output directory. Default: ./output/
• --s: (Optional) Number of DFF to lock. Default: 1

Example:

python3 structuralEncryptor.py --file_name example.txt --keys "3 4" --output_dir "./encrypted_output/" --s 2

Single Test

Run the run_file_encryption_structural.sh script with a seq.bench file:

./run_file_encryption_structural.sh ./location/to/seq.bench

Multiple Tests

To run tests on multiple .bench files in a directory, edit the directory path in the run_m_structual.sh script, then run:

./run_m_structual.sh

Citation

@INPROCEEDINGS{Cute-Lock,
  author={Lopez, Kevin and Rezaei, Amin},
  booktitle={2025 Design, Automation & Test in Europe Conference & Exhibition (DATE)}, 
  title={Cute-Lock: Behavioral and Structural Multi-Key Logic Locking Using Time Base Keys}, 
  year={2025},
  volume={},
  number={},
  pages={1-7},
  doi={10.23919/DATE64628.2025.10993182}
  }

License

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