rln-contract/docs/index.md

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Solidity API

IVerifier

verifyProof

function verifyProof(uint256[2] a, uint256[2][2] b, uint256[2] c, uint256[2] input) external view returns (bool)

IPoseidonHasher

hash

function hash(uint256[2] inputs) external pure returns (uint256 result)

Hashes the input using the Poseidon hash function, n = 2

Parameters

Name Type Description
inputs uint256[2] The input to hash

PoseidonHasher

Q

uint256 Q

hash

function hash(uint256[2] inputs) external pure returns (uint256 result)

Hashes the input using the Poseidon hash function, n = 2

Parameters

Name Type Description
inputs uint256[2] The input to hash

RLN

constructor

constructor(uint256 membershipDeposit, uint256 depth, address _poseidonHasher, address _verifier) public

_validateRegistration

function _validateRegistration(uint256 idCommitment) internal pure

Inheriting contracts MUST override this function

_validateSlash

function _validateSlash(uint256 idCommitment, address payable receiver, uint256[8] proof) internal pure

FullTree

error FullTree()

The tree is full

InsufficientDeposit

error InsufficientDeposit(uint256 required, uint256 provided)

Invalid deposit amount

Parameters

Name Type Description
required uint256 The required deposit amount
provided uint256 The provided deposit amount

DuplicateIdCommitment

error DuplicateIdCommitment()

Member is already registered

FailedValidation

error FailedValidation()

Failed validation on registration/slashing

InvalidIdCommitment

error InvalidIdCommitment(uint256 idCommitment)

Invalid idCommitment

InvalidReceiverAddress

error InvalidReceiverAddress(address to)

Invalid receiver address, when the receiver is the contract itself or 0x0

MemberNotRegistered

error MemberNotRegistered(uint256 idCommitment)

Member is not registered

MemberHasNoStake

error MemberHasNoStake(uint256 idCommitment)

Member has no stake

InsufficientWithdrawalBalance

error InsufficientWithdrawalBalance()

User has insufficient balance to withdraw

InsufficientContractBalance

error InsufficientContractBalance()

Contract has insufficient balance to return

InvalidProof

error InvalidProof()

Invalid proof

RlnBase

MEMBERSHIP_DEPOSIT

uint256 MEMBERSHIP_DEPOSIT

The deposit amount required to register as a member

DEPTH

uint256 DEPTH

The depth of the merkle tree

SET_SIZE

uint256 SET_SIZE

The size of the merkle tree, i.e 2^depth

idCommitmentIndex

uint256 idCommitmentIndex

The index of the next member to be registered

stakedAmounts

mapping(uint256 => uint256) stakedAmounts

The amount of eth staked by each member maps from idCommitment to the amount staked

members

mapping(uint256 => uint256) members

The membership status of each member maps from idCommitment to their index in the set

memberExists

mapping(uint256 => bool) memberExists

The membership status of each member

withdrawalBalance

mapping(address => uint256) withdrawalBalance

The balance of each user that can be withdrawn

poseidonHasher

contract PoseidonHasher poseidonHasher

The Poseidon hasher contract

verifier

contract IVerifier verifier

The groth16 verifier contract

deployedBlockNumber

uint32 deployedBlockNumber

the deployed block number

imtData

struct BinaryIMTData imtData

the Incremental Merkle Tree

MemberRegistered

event MemberRegistered(uint256 idCommitment, uint256 index)

Emitted when a new member is added to the set

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member
index uint256 The index of the member in the set

MemberWithdrawn

event MemberWithdrawn(uint256 idCommitment, uint256 index)

Emitted when a member is removed from the set

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member
index uint256 The index of the member in the set

onlyValidIdCommitment

modifier onlyValidIdCommitment(uint256 idCommitment)

constructor

constructor(uint256 membershipDeposit, uint256 depth, address _poseidonHasher, address _verifier) internal

register

function register(uint256 idCommitment) external payable virtual

Allows a user to register as a member

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member

_register

function _register(uint256 idCommitment, uint256 stake) internal virtual

Registers a member

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member
stake uint256 The amount of eth staked by the member

_validateRegistration

function _validateRegistration(uint256 idCommitment) internal view virtual

Inheriting contracts MUST override this function

slash

function slash(uint256 idCommitment, address payable receiver, uint256[8] proof) external virtual

Allows a user to slash a member

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member
receiver address payable
proof uint256[8]

_slash

function _slash(uint256 idCommitment, address payable receiver, uint256[8] proof) internal virtual

Slashes a member by removing them from the set, and adding their stake to the receiver's available withdrawal balance

Parameters

Name Type Description
idCommitment uint256 The idCommitment of the member
receiver address payable The address to receive the funds
proof uint256[8]

_validateSlash

function _validateSlash(uint256 idCommitment, address payable receiver, uint256[8] proof) internal view virtual

withdraw

function withdraw() external virtual

Allows a user to withdraw funds allocated to them upon slashing a member

isValidCommitment

function isValidCommitment(uint256 idCommitment) public view returns (bool)

_verifyProof

function _verifyProof(uint256 idCommitment, address receiver, uint256[8] proof) internal view virtual returns (bool)

Groth16 proof verification

root

function root() external view returns (uint256)

Pairing

G1Point

struct G1Point {
  uint256 X;
  uint256 Y;
}

G2Point

struct G2Point {
  uint256[2] X;
  uint256[2] Y;
}

P1

function P1() internal pure returns (struct Pairing.G1Point)

Return Values

Name Type Description
[0] struct Pairing.G1Point the generator of G1

P2

function P2() internal pure returns (struct Pairing.G2Point)

Return Values

Name Type Description
[0] struct Pairing.G2Point the generator of G2

negate

function negate(struct Pairing.G1Point p) internal pure returns (struct Pairing.G1Point r)

Return Values

Name Type Description
r struct Pairing.G1Point the negation of p, i.e. p.addition(p.negate()) should be zero.

addition

function addition(struct Pairing.G1Point p1, struct Pairing.G1Point p2) internal view returns (struct Pairing.G1Point r)

Return Values

Name Type Description
r struct Pairing.G1Point the sum of two points of G1

scalar_mul

function scalar_mul(struct Pairing.G1Point p, uint256 s) internal view returns (struct Pairing.G1Point r)

Return Values

Name Type Description
r struct Pairing.G1Point the product of a point on G1 and a scalar, i.e. p == p.scalar_mul(1) and p.addition(p) == p.scalar_mul(2) for all points p.

pairing

function pairing(struct Pairing.G1Point[] p1, struct Pairing.G2Point[] p2) internal view returns (bool)

Return Values

Name Type Description
[0] bool the result of computing the pairing check e(p1[0], p2[0]) _ .... _ e(p1[n], p2[n]) == 1 For example pairing([P1(), P1().negate()], [P2(), P2()]) should return true.

pairingProd2

function pairingProd2(struct Pairing.G1Point a1, struct Pairing.G2Point a2, struct Pairing.G1Point b1, struct Pairing.G2Point b2) internal view returns (bool)

Convenience method for a pairing check for two pairs.

pairingProd3

function pairingProd3(struct Pairing.G1Point a1, struct Pairing.G2Point a2, struct Pairing.G1Point b1, struct Pairing.G2Point b2, struct Pairing.G1Point c1, struct Pairing.G2Point c2) internal view returns (bool)

Convenience method for a pairing check for three pairs.

pairingProd4

function pairingProd4(struct Pairing.G1Point a1, struct Pairing.G2Point a2, struct Pairing.G1Point b1, struct Pairing.G2Point b2, struct Pairing.G1Point c1, struct Pairing.G2Point c2, struct Pairing.G1Point d1, struct Pairing.G2Point d2) internal view returns (bool)

Convenience method for a pairing check for four pairs.

Verifier

VerifyingKey

struct VerifyingKey {
  struct Pairing.G1Point alfa1;
  struct Pairing.G2Point beta2;
  struct Pairing.G2Point gamma2;
  struct Pairing.G2Point delta2;
  struct Pairing.G1Point[] IC;
}

Proof

struct Proof {
  struct Pairing.G1Point A;
  struct Pairing.G2Point B;
  struct Pairing.G1Point C;
}

verifyingKey

function verifyingKey() internal pure returns (struct Verifier.VerifyingKey vk)

verify

function verify(uint256[] input, struct Verifier.Proof proof) internal view returns (uint256)

verifyProof

function verifyProof(uint256[2] a, uint256[2][2] b, uint256[2] c, uint256[2] input) public view returns (bool r)

Return Values

Name Type Description
r bool bool true if proof is valid