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

C12

uint256 C12

C13

uint256 C13

C14

uint256 C14

C15

uint256 C15

C16

uint256 C16

C17

uint256 C17

C18

uint256 C18

C19

uint256 C19

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uint256 C20

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uint256 C21

C22

uint256 C22

C23

uint256 C23

C24

uint256 C24

C25

uint256 C25

C26

uint256 C26

C27

uint256 C27

C28

uint256 C28

C29

uint256 C29

C30

uint256 C30

C31

uint256 C31

C32

uint256 C32

C33

uint256 C33

C34

uint256 C34

C35

uint256 C35

C36

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 C41

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uint256 C42

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uint256 C43

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uint256 C44

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uint256 C45

C46

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uint256 C47

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uint256 C48

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uint256 C49

C50

uint256 C50

C51

uint256 C51

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uint256 C52

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uint256 C53

C54

uint256 C54

C55

uint256 C55

C56

uint256 C56

C57

uint256 C57

C58

uint256 C58

C59

uint256 C59

C60

uint256 C60

C61

uint256 C61

C62

uint256 C62

C63

uint256 C63

C64

uint256 C64

C65

uint256 C65

C66

uint256 C66

C67

uint256 C67

C68

uint256 C68

C69

uint256 C69

C70

uint256 C70

C71

uint256 C71

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uint256 C72

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uint256 C73

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uint256 C74

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uint256 C75

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uint256 C76

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uint256 C77

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uint256 C78

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uint256 C79

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uint256 C80

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uint256 C81

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uint256 C82

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uint256 C83

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uint256 C84

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uint256 C85

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uint256 C86

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uint256 C87

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uint256 C88

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uint256 C89

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uint256 C90

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uint256 C92

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uint256 C93

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uint256 C94

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uint256 C95

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uint256 C96

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uint256 C97

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uint256 C98

C99

uint256 C99

C100

uint256 C100

C101

uint256 C101

C102

uint256 C102

C103

uint256 C103

C104

uint256 C104

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uint256 C105

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uint256 C106

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uint256 C107

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uint256 C108

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uint256 C109

C110

uint256 C110

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uint256 C111

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uint256 C112

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uint256 C113

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uint256 C114

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uint256 C115

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uint256 C116

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uint256 C117

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uint256 C118

C119

uint256 C119

C120

uint256 C120

C121

uint256 C121

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

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

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

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

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

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

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