1 unstable release
0.2.0  Dec 22, 2021 

#297 in Science
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Used in plonkpallet
600KB
14K
SLoC
PLONK
This is a pure Rust implementation of the PLONK proving system over BLS12381
This library contains a modularised implementation of KZG10 as the default polynomial commitment scheme.
Usage
use fullcodec_plonk::prelude::*;
use rand::SeedableRng;
use rand_xorshift::XorShiftRng;
use rand_core::RngCore;
// Implement a circuit that checks:
// 1) a + b = c where C is a PI
// 2) a <= 2^6
// 3) b <= 2^5
// 4) a * b = d where D is a PI
// 5) JubJub::GENERATOR * e(JubJubScalar) = f where F is a Public Input
#[derive(Debug, Default)]
pub struct TestCircuit {
a: BlsScalar,
b: BlsScalar,
c: BlsScalar,
d: BlsScalar,
e: JubJubScalar,
f: JubJubAffine,
}
impl Circuit for TestCircuit {
const CIRCUIT_ID: [u8; 32] = [0xff; 32];
fn gadget(
&mut self,
composer: &mut TurboComposer,
) > Result<(), Error> {
let a = composer.append_witness(self.a);
let b = composer.append_witness(self.b);
// Make first constraint a + b = c
let constraint = Constraint::new()
.left(1)
.right(1)
.public(self.c)
.a(a)
.b(b);
composer.append_gate(constraint);
// Check that a and b are in range
composer.component_range(a, 1 << 6);
composer.component_range(b, 1 << 5);
// Make second constraint a * b = d
let constraint = Constraint::new()
.mult(1)
.output(1)
.public(self.d)
.a(a)
.b(b);
composer.append_gate(constraint);
let e = composer.append_witness(self.e);
let scalar_mul_result = composer
.component_mul_generator(e, dusk_jubjub::GENERATOR_EXTENDED);
// Apply the constrain
composer.assert_equal_public_point(scalar_mul_result, self.f);
Ok(())
}
fn public_inputs(&self) > Vec<PublicInputValue> {
vec![self.c.into(), self.d.into(), self.f.into()]
}
fn padded_gates(&self) > usize {
1 << 11
}
}
// Now let's use the Circuit we've just implemented!
let rng = XorShiftRng::from_seed([
0x59, 0x62, 0xbe, 0x5d, 0x76, 0x3d, 0x31, 0x8d, 0x17, 0xdb, 0x37,
0x32, 0x54, 0x06, 0xbc, 0xe5,
]);
let pp = PublicParameters::setup(1 << 12, rng).unwrap();
// Initialize the circuit
let mut circuit = TestCircuit::default();
// Compile the circuit
let (pk, vd) = circuit.compile(&pp).unwrap();
// Prover POV
let proof = {
let mut circuit = TestCircuit {
a: BlsScalar::from(20u64),
b: BlsScalar::from(5u64),
c: BlsScalar::from(25u64),
d: BlsScalar::from(100u64),
e: JubJubScalar::from(2u64),
f: JubJubAffine::from(
dusk_jubjub::GENERATOR_EXTENDED * JubJubScalar::from(2u64),
),
};
circuit.prove(&pp, &pk, b"Test").unwrap()
};
// Verifier POV
let public_inputs: Vec<PublicInputValue> = vec![
BlsScalar::from(25u64).into(),
BlsScalar::from(100u64).into(),
JubJubAffine::from(
dusk_jubjub::GENERATOR_EXTENDED * JubJubScalar::from(2u64),
)
.into(),
];
TestCircuit::verify(
&pp,
&vd,
&proof,
&public_inputs,
b"Test",
).unwrap();
Features
This crate includes a variety of features which will briefly be explained below:
alloc
: Enables the usage of an allocator and with it the capability of performingProof
constructions and verifications. Without this feature it IS NOT possible to prove or verify anything. Its absence only makesduskplonk
export certain fixedsize data structures such asProof
which can be useful in no_std envoirments where we don't have allocators either.std
: Enablesstd
usage as well asrayon
parallelisation in some proving and verifying ops. It also uses thestd
versions of the elliptic curve deps, which utilises theparallel
feature fromduskbls12381
. By default, this is the feature that comes enabled with the crate.trace
: Enables the Circuit debugger tooling. This is essentially the capability of using theStandardComposer::check_circuit_satisfied
function. The function will output information about each circuit gate until one of the gates does not satisfy the equation, or there are no more gates. If there is an unsatisfied gate equation, the function will panic and return the gate number.traceprint
: Goes a step further thantrace
and prints eachgate
component data, giving a clear overview of all the values which make up the circuit that we're constructing. The recommended method is to derive the std output, and the std error, and then place them in text file which can be used to efficiently analyse the gates.canon
: Enablescanonical
serialisation for particular data structures, which is very useful in integrating this library within the rest of the Dusk stack  especially for storage purposes.
Documentation
There are two main types of documentation in this repository:

Crate documentation. This provides info about all of the functions that the library provides, as well as the documentation regarding the data structures that it exports. To check this, please feel free to go to the documentation page or run
make doc
ormake docinternal
. 
Notes. This is a specific subset of documentation which explains the key mathematical concepts of PLONK and how they work with mathematical demonstrations. To check it, run
make doc
and open the resulting docs, which will be located under/target
with your browser.
Performance
Benchmarks taken on Intel(R) Core(TM) i99900X CPU @ 3.50GHz
For a circuitsize of 2^16
constraints/gates:
 Proving time:
5.46s
 Verification time:
9.34ms
. (This time will not vary depending on the circuitsize.)
For more results, please run cargo bench
to get a full report of benchmarks in respect of constraint numbers.
Acknowledgements
 Reference implementation AztecProtocol/Barretenberg
 FFT Module and KZG10 Module were taken and modified from zexe/zcash and sciprlab, respectively.
Licensing
This code is licensed under Mozilla Public License Version 2.0 (MPL2.0). Please see LICENSE for further info.
About
Implementation designed by the dusk team.
Contributing
 If you want to contribute to this repository/project please, check CONTRIBUTING.md
 If you want to report a bug or request a new feature addition, please open an issue on this repository.
Dependencies
~4–8.5MB
~151K SLoC