rln-contract/docs/index.md

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 input) external pure returns (uint256 result)

Hashes the input using the Poseidon hash function, n = 2, second input is the constant 0

Parameters

Name	Type	Description
input	uint256	The input to hash

PoseidonHasher

Q

uint256 Q

C0

uint256 C0

C1

uint256 C1

C2

uint256 C2

C3

uint256 C3

C4

uint256 C4

C5

uint256 C5

C6

uint256 C6

C7

uint256 C7

C8

uint256 C8

C9

uint256 C9

C10

uint256 C10

C11

uint256 C11

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uint256 C12

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uint256 C13

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uint256 C14

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uint256 C15

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uint256 C16

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uint256 C17

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uint256 C18

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uint256 C19

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uint256 C20

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uint256 C21

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uint256 C22

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uint256 C23

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uint256 C24

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uint256 C25

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uint256 C26

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uint256 C27

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uint256 C28

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uint256 C29

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uint256 C30

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uint256 C31

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uint256 C32

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uint256 C33

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uint256 C34

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uint256 C35

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uint256 C36

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uint256 C37

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uint256 C38

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uint256 C39

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uint256 C40

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uint256 C43

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uint256 C45

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uint256 C47

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uint256 C48

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uint256 C49

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uint256 C50

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uint256 C52

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uint256 C53

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uint256 C54

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uint256 C55

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uint256 C56

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uint256 C57

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uint256 C58

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uint256 C59

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uint256 C60

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uint256 C61

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uint256 C62

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uint256 C63

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uint256 C64

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uint256 C65

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uint256 C66

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uint256 C67

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uint256 C68

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uint256 C69

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uint256 C70

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uint256 C72

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uint256 C75

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uint256 C79

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uint256 C80

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uint256 C100

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uint256 C104

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uint256 C110

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uint256 C119

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uint256 C120

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C122

uint256 C122

C123

uint256 C123

C124

uint256 C124

C125

uint256 C125

C126

uint256 C126

C127

uint256 C127

M00

uint256 M00

M01

uint256 M01

M10

uint256 M10

M11

uint256 M11

hash

function hash(uint256 input) external pure returns (uint256 result)

Hashes the input using the Poseidon hash function, n = 2, second input is the constant 0

Parameters

Name	Type	Description
input	uint256	The input to hash

_hash

function _hash(uint256 input) internal pure returns (uint256 result)

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

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

withdrawalBalance

mapping(address => uint256) withdrawalBalance

The balance of each user that can be withdrawn

poseidonHasher

contract IPoseidonHasher poseidonHasher

The Poseidon hasher contract

verifier

contract IVerifier verifier

The groth16 verifier contract

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

constructor

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

register

function register(uint256 idCommitment) external payable

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

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

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

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

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

hash

function hash(uint256 input) internal view returns (uint256)

Hashes a value using the Poseidon hasher NOTE: The variant of Poseidon we use accepts only 1 input, assume n=2, and the second input is 0

Parameters

Name	Type	Description
input	uint256	The value to hash

_verifyProof

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

Groth16 proof verification

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