Setup

• Install dependencies: pip install -r requirements.txt

Input Format

To run the scripts, we will need three files as input:

1. circuit_file

This file contains the circuit to be computed. It also contains which inputs are assigned to Alice and which to Bob.

Format

• The file starts with a description of the circuit
  • Each line contains a gate or a terminal (A terminal simply means a input)
  • terminals are represented as term <name>.
  • gates are represented as
    • binary gates: <gate_type> <input1> <input2> <identifier>
    • unary gates: <gate_type> <input> <identifier>
    • identifier is an identifier for the gate used for later inputs
    • each <input> should be a previusly defined terminal or gate
• The gate description ends with a line describing the output in the format output <identifier>
  • identifier is the identifier of the gate that produces the output and must be previously defined.
• Finally, the file ends with two lines:
  • a1 a2 ... an where a0, a1, a2 are the identifiers of the inputs assigned to alice
  • b1 b2 ... bm where b0, b1, b2 are the identifiers of the inputs assigned to bob
• Empty lines and lines starting with # are ignored. So, we can add comments to the file using #
• Allowed gates are and, or, not.

Example

# This is a comment
term a0
term a1
term b0
term b1
  
not a0 na0
and na0 a1 x
and b0 b1 b
or x b out
  
output out
  
a0 a1
b0 b1

2. alice_assignment_file

This file contains the values assigned to alice's inputs. It should contain assignments for all inputs assigned to alice in the circuit file.

Format: Each line contains input_name value. Empty lines and lines starting with # are ignored.

Example:

a0 1
a1 0

3. bob_assignment_file

Similar to alice_assignment_file, but for bob's inputs.

Scripts

There are two scripts to run:

1. bob.py

This script acts as bob and uses circuit_file and bob_assignment_file. In addition, it also acts as the server for communication with alice

Usage: python bob.py <port> <circuit_file> <bob_assignment_file> [--verbose]

Example: python bob.py 12345 circuit.txt bob.txt --verbose

2. alice.py

This script acts as alice and uses circuit_file and alice_assignment_file. It acts as the client for communication with bob

Usage: python alice.py <ip> <port> <circuit_file> <alice_assignment_file> [--verbose]

Here ip and port are the ip and port of bob.py.

Example: python alice.py localhost 12345 circuit.txt alice.txt --verbose

Quick Testing Scripts

run.sh

If we are running both scripts on the same machine, we can use the script run.sh to run both scripts in parallel.

First we put the three files in the same directoory and name them as circuit.txt, bob.txt and alice.txt. Then we run the script as follows: ./run.sh <port> <directory>

stresstester.py

This script can be used to test the protocol for multiple assignments.

For each possible assignment of the inputs, the script will calculate the output of the circuit using two methods: direct evaluation of the circuit and garbled circuit protocol using alice.py and bob.py and report if the outputs differ for any assignment.

Usage: python stresstester.py <testcase_folder> <port> [iterations] Example: python stresstester.py testcases/millionaire2 12345 10

This will run the protocol for 10 random assignments for the 2 bit millionaire problem. If no iterations are provided, it will run for all possible assignments.

Testcases:

There are three testcases in the testcases directory.

• millionaire2 is the millionaire problem with 2 bits.
• millionaire4 is the millionaire problem with 4 bits.
• mux is a simple 4 bit multiplexer.

Example: ./run.sh 12345 testcases/millionaire2

Running via GitHub Actions

A github action "Garbled Circuits Demonstration" is available. To run, go to the Actions tab, select "Garbled Circuits Demonstration" and click “Run workflow”. The inputs are:

• testcase: Name of the test (e.g., millionaire2, millionaire4, mux)
• alice_inputs: Alice's inputs. Use \n to separate lines. Example: "a1 1\na0 0"
• bob_inputs: Bob's input. Same format as above
• verbose: Optional, default is true

There should be a folder './testcases//' with the a circuit.txt file describing the circuit. Three testcases are already provided in the testcases folder. The testcases are:

• millionaire2: 2 bit millionaire problem
• millionaire4: 4 bit millionaire problem
• mux: 4 bit multiplexer

To add a new testcase, create a folder with the name of the testcase and add a circuit.txt file with the description of the circuit. The format is the same as described above. All inputs should be assigned to exactly one of alice or bob.

🧾 Examples

millionaire2

• testcase: millionaire2
• alice_inputs: a1 1\na0 0
• bob_inputs: b1 0\nb0 1

millionaire4

• testcase: millionaire4
• alice_inputs: a3 1\na2 0\na1 1\na0 0
• bob_inputs: b3 0\nb2 1\nb1 0\nb0 1

mux

- `testcase`: `mux` - `alice_inputs`: `a0 1\na1 0\na2 1\na3 1` - `bob_inputs`: `b0 1\nb1 0`