zksnake

Python implementation of zk-SNARKs (Zero Knowledge Succint Non-interactive ARgument of Knowledge) using simple symbolic expression.

Warning

This library is intended to be used as proof of concept, prototyping, and educational purpose only. It is still unstable and not fully tested!

Proving schemes and curves

zksnake currently only supports Groth16 and PlonK (original version) along with BN254 and BLS12-381 as supported curves. More proving schemes will be implemented in the future (hopefully).

Usage

Build constraints

from zksnake.arithmetization import Var, ConstraintSystem, R1CS
from zksnake.constant import BN254_SCALAR_FIELD

x = Var('x')
y = Var('y')
v1 = Var('v1')

# prove the solution of y == x**3 + x + 5
# with x as input and y as output
cs = ConstraintSystem(['x'], ['y'], BN254_SCALAR_FIELD)
cs.add_constraint(v1 == x * x)
cs.add_constraint(y - 5 - x == v1 * x)
cs.set_public(y)

r1cs = R1CS(cs)
r1cs.compile()

Alternatively, you can import the constraints from Circom:

from zksnake.arithmetization import R1CS

r1cs = R1CS.from_file("circuit.r1cs", "circuit.sym")
r1cs.compile()

Note that some constraints that are complex or expensive (require off-circuit computation) cannot be imported directly and require you to add "hint" function to pre-define the variable value (see Example).

Prove and verify proof

from zksnake.groth16 import Groth16

# trusted setup
proof_system = Groth16(r1cs)
proof_system.setup()

# solve the constraint system
solution = r1cs.solve({'x': 3})
public_witness, private_witness = r1cs.generate_witness(solution)

# proving
proof = proof_system.prove(public_witness, private_witness)

# verification
assert proof_system.verify(proof, public_witness)

Development

Requirements:

• python3 >= 3.9
• rust >= 1.77

Install maturin:

pip install maturin

Setup virtual environment:

python3 -m venv .venv
source .venv/bin/activate

Compile and install the editable module into venv:

maturin develop -r -E dev

Test the script:

python3 -m pytest tests