Update to RLN v2 (#21)

go.mod

@@ -4,10 +4,11 @@ go 1.19
 
 require (
 	github.com/consensys/gnark-crypto v0.12.1
+	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.8.4
-	github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240124080743-37fbb869c330
+	github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240523161310-d005fe7ba59c
-	github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240124081101-5e4387508113
+	github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240523161300-8203361a01d0
-	github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240124081123-f90cfc88a1dc
+	github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240523161247-6f16d12c5a86
 	golang.org/x/crypto v0.18.0
 )
 

go.sum

@@ -3,6 +3,7 @@ github.com/bits-and-blooms/bitset v1.10.0/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6
 github.com/consensys/gnark-crypto v0.12.1 h1:lHH39WuuFgVHONRl3J0LRBtuYdQTumFSDtJF7HpyG8M=
 github.com/consensys/gnark-crypto v0.12.1/go.mod h1:v2Gy7L/4ZRosZ7Ivs+9SfUDr0f5UlG+EM5t7MPHiLuY=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -13,19 +14,32 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
+github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240124080743-37fbb869c330 h1:TJmn6GQ5HpxdZraZn6DjUqWy8UV+8pB4yWcsWFAngqE=
+github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240522110429-626138029176 h1:ezeAofaW3B6tfqS06FwKAKKXpNkimWnIwKjDU0dDPKE=
-github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240124080743-37fbb869c330/go.mod h1:KYykqtdApHVYZ3G0spwMnoxc5jH5eI3jyO9SwsSfi48=
+github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240522110429-626138029176/go.mod h1:KYykqtdApHVYZ3G0spwMnoxc5jH5eI3jyO9SwsSfi48=
+github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240523161310-d005fe7ba59c h1:/eGH8EAt5/zGfNRBQ0nJMrfZDeXRSJrm8E8uCPlsC3A=
+github.com/waku-org/go-zerokit-rln-apple v0.0.0-20240523161310-d005fe7ba59c/go.mod h1:KYykqtdApHVYZ3G0spwMnoxc5jH5eI3jyO9SwsSfi48=
 github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240124081101-5e4387508113 h1:dPwc4LAWLXb4Pssej/NtGA9A0UMQwi+JafQPdnhjRWM=
 github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240124081101-5e4387508113/go.mod h1:7cSGUoGVIla1IpnChrLbkVjkYgdOcr7rcifEfh4ReR4=
+github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240523161300-8203361a01d0 h1:IvtkZOcApOkEmHkT/drDmMtY6fdYpF7x4sesWyIURpI=
+github.com/waku-org/go-zerokit-rln-arm v0.0.0-20240523161300-8203361a01d0/go.mod h1:7cSGUoGVIla1IpnChrLbkVjkYgdOcr7rcifEfh4ReR4=
 github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240124081123-f90cfc88a1dc h1:GUZlr25hXLu/PeASqm8P5dPOyD4CdfvkzyEtXEBLbr8=
 github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240124081123-f90cfc88a1dc/go.mod h1:+LeEYoW5/uBUTVjtBGLEVCUe9mOYAlu5ZPkIxLOSr5Y=
+github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240523161247-6f16d12c5a86 h1:PN1WSt3u/DEIn4hX5Oqrm9bm5nf5VBfenfXmbX4mg60=
+github.com/waku-org/go-zerokit-rln-x86_64 v0.0.0-20240523161247-6f16d12c5a86/go.mod h1:+LeEYoW5/uBUTVjtBGLEVCUe9mOYAlu5ZPkIxLOSr5Y=
 golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
 golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

rln/link/apple.go

@@ -5,7 +5,11 @@
 
 package link
 
-import r "github.com/waku-org/go-zerokit-rln-apple/rln"
+import (
+	"errors"
+
+	r "github.com/waku-org/go-zerokit-rln-apple/rln"
+)
 
 type RLNWrapper struct {
 	ffi *r.RLN
@@ -92,7 +96,8 @@ func (i RLNWrapper) GenerateRLNProof(input []byte) ([]byte, error) {
 }
 
 func (i RLNWrapper) GenerateRLNProofWithWitness(input []byte) ([]byte, error) {
-	return i.ffi.GenerateRLNProofWithWitness(input)
+	return nil, errors.New("not implemented")
+	//return i.ffi.GenerateRLNProofWithWitness(input)
 }
 
 func (i RLNWrapper) VerifyWithRoots(input []byte, roots []byte) (bool, error) {

rln/link/arm.go

@@ -4,7 +4,11 @@
 
 package link
 
-import r "github.com/waku-org/go-zerokit-rln-arm/rln"
+import (
+	"errors"
+
+	r "github.com/waku-org/go-zerokit-rln-arm/rln"
+)
 
 type RLNWrapper struct {
 	ffi *r.RLN
@@ -91,7 +95,8 @@ func (i RLNWrapper) GenerateRLNProof(input []byte) ([]byte, error) {
 }
 
 func (i RLNWrapper) GenerateRLNProofWithWitness(input []byte) ([]byte, error) {
-	return i.ffi.GenerateRLNProofWithWitness(input)
+	return nil, errors.New("not implemented")
+	//return i.ffi.GenerateRLNProofWithWitness(input)
 }
 
 func (i RLNWrapper) VerifyWithRoots(input []byte, roots []byte) (bool, error) {

rln/link/x86_64.go

@@ -5,7 +5,11 @@
 
 package link
 
-import r "github.com/waku-org/go-zerokit-rln-x86_64/rln"
+import (
+	"errors"
+
+	r "github.com/waku-org/go-zerokit-rln-x86_64/rln"
+)
 
 type RLNWrapper struct {
 	ffi *r.RLN
@@ -92,7 +96,8 @@ func (i RLNWrapper) GenerateRLNProof(input []byte) ([]byte, error) {
 }
 
 func (i RLNWrapper) GenerateRLNProofWithWitness(input []byte) ([]byte, error) {
-	return i.ffi.GenerateRLNProofWithWitness(input)
+	return nil, errors.New("not implemented")
+	//return i.ffi.GenerateRLNProofWithWitness(input)
 }
 
 func (i RLNWrapper) VerifyWithRoots(input []byte, roots []byte) (bool, error) {

rln/rln.go

@@ -14,6 +14,8 @@ import (
 // Prevents a RLN ZK proof generated for one application to be re-used in another one.
 var RLN_IDENTIFIER = [32]byte{166, 140, 43, 8, 8, 22, 206, 113, 151, 128, 118, 40, 119, 197, 218, 174, 11, 117, 84, 228, 96, 211, 212, 140, 145, 104, 146, 99, 24, 192, 217, 4}
 
+var DEFAULT_USER_MESSAGE_LIMIT = uint32(10)
+
 // RLN represents the context used for rln.
 type RLN struct {
 	w *link.RLNWrapper
@@ -91,12 +93,14 @@ func (r *RLN) InitTreeWithMembers(idComms []IDCommitment) error {
 	return nil
 }
 
-func toIdentityCredential(generatedKeys []byte) (*IdentityCredential, error) {
+func toIdentityCredential(generatedKeys []byte, userMessageLimit uint32) (*IdentityCredential, error) {
+	// add user message limit
 	key := &IdentityCredential{
 		IDTrapdoor:       [32]byte{},
 		IDNullifier:      [32]byte{},
 		IDSecretHash:     [32]byte{},
 		IDCommitment:     [32]byte{},
+		UserMessageLimit: userMessageLimit,
 	}
 
 	if len(generatedKeys) != 32*4 {
@@ -113,23 +117,45 @@ func toIdentityCredential(generatedKeys []byte) (*IdentityCredential, error) {
 
 // MembershipKeyGen generates a IdentityCredential that can be used for the
 // registration into the rln membership contract. Returns an error if the key generation fails
-func (r *RLN) MembershipKeyGen() (*IdentityCredential, error) {
+// Accepts an optional parameter that sets the user message limit which defaults
+// to DEFAULT_USER_MESSAGE_LIMIT
+func (r *RLN) MembershipKeyGen(userMessageLimitParam ...uint32) (*IdentityCredential, error) {
+	var userMessageLimit uint32
+	if len(userMessageLimitParam) == 1 {
+		userMessageLimit = userMessageLimitParam[0]
+	} else if len(userMessageLimitParam) == 0 {
+		userMessageLimit = DEFAULT_USER_MESSAGE_LIMIT
+	} else {
+		return nil, errors.New("just one user message limit is allowed")
+	}
+
 	generatedKeys := r.w.ExtendedKeyGen()
 	if generatedKeys == nil {
 		return nil, errors.New("error in key generation")
 	}
-	return toIdentityCredential(generatedKeys)
+	return toIdentityCredential(generatedKeys, userMessageLimit)
 }
 
 // SeededMembershipKeyGen generates a deterministic IdentityCredential using a seed
 // that can be used for the registration into the rln membership contract.
 // Returns an error if the key generation fails
-func (r *RLN) SeededMembershipKeyGen(seed []byte) (*IdentityCredential, error) {
+// Accepts an optional parameter that sets the user message limit which defaults
+// to DEFAULT_USER_MESSAGE_LIMIT
+func (r *RLN) SeededMembershipKeyGen(seed []byte, userMessageLimitParam ...uint32) (*IdentityCredential, error) {
+	var userMessageLimit uint32
+	if len(userMessageLimitParam) == 1 {
+		userMessageLimit = userMessageLimitParam[0]
+	} else if len(userMessageLimitParam) == 0 {
+		userMessageLimit = DEFAULT_USER_MESSAGE_LIMIT
+	} else {
+		return nil, errors.New("just one user message limit is allowed")
+	}
+
 	generatedKeys := r.w.ExtendedSeededKeyGen(seed)
 	if generatedKeys == nil {
 		return nil, errors.New("error in key generation")
 	}
-	return toIdentityCredential(generatedKeys)
+	return toIdentityCredential(generatedKeys, userMessageLimit)
 }
 
 // appendLength returns length prefixed version of the input with the following format
@@ -181,65 +207,61 @@ func (r *RLN) Poseidon(input ...[]byte) (MerkleNode, error) {
 	return result, nil
 }
 
-func (r *RLN) ExtractMetadata(proof RateLimitProof) (ProofMetadata, error) {
-	externalNullifierRes, err := r.Poseidon(proof.Epoch[:], proof.RLNIdentifier[:])
-	if err != nil {
-		return ProofMetadata{}, fmt.Errorf("could not construct the external nullifier: %w", err)
-	}
-
-	return ProofMetadata{
-		Nullifier:         proof.Nullifier,
-		ShareX:            proof.ShareX,
-		ShareY:            proof.ShareY,
-		ExternalNullifier: externalNullifierRes,
-	}, nil
-}
-
 // GenerateProof generates a proof for the RLN given a KeyPair and the index in a merkle tree.
 // The output will containt the proof data and should be parsed as |proof<128>|root<32>|epoch<32>|share_x<32>|share_y<32>|nullifier<32>|
 // integers wrapped in <> indicate value sizes in bytes
-func (r *RLN) GenerateProof(data []byte, key IdentityCredential, index MembershipIndex, epoch Epoch) (*RateLimitProof, error) {
+func (r *RLN) GenerateProof(
-	input := serialize(key.IDSecretHash, index, epoch, data)
+	data []byte,
+	key IdentityCredential,
+	index MembershipIndex,
+	epoch Epoch,
+	messageId uint32) (*RateLimitProof, error) {
+
+	externalNullifierInput, err := r.Poseidon(epoch[:], RLN_IDENTIFIER[:])
+	if err != nil {
+		return nil, fmt.Errorf("could not construct the external nullifier: %w", err)
+	}
+
+	input := serialize(key.IDSecretHash, index, key.UserMessageLimit, messageId, externalNullifierInput, data)
 	proofBytes, err := r.w.GenerateRLNProof(input)
 	if err != nil {
 		return nil, err
 	}
 
-	if len(proofBytes) != 320 {
+	expectedBytes := 288
-		return nil, errors.New("invalid proof generated")
+	if len(proofBytes) != expectedBytes {
+		return nil, fmt.Errorf("invalid proof generated. size: %d expected: %d",
+			len(proofBytes), expectedBytes)
 	}
 
-	// parse the proof as [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]
+	// parse proof taken from: https://github.com/vacp2p/zerokit/blob/v0.5.0/rln/src/public.rs#L750
+	// [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
 	proofOffset := 128
 	rootOffset := proofOffset + 32
-	epochOffset := rootOffset + 32
+	externalNullifierOffset := rootOffset + 32
-	shareXOffset := epochOffset + 32
+	shareXOffset := externalNullifierOffset + 32
 	shareYOffset := shareXOffset + 32
 	nullifierOffset := shareYOffset + 32
-	rlnIdentifierOffset := nullifierOffset + 32
 
 	var zkproof ZKSNARK
 	var proofRoot, shareX, shareY MerkleNode
-	var epochR Epoch
+	var externalNullifier Nullifier
 	var nullifier Nullifier
-	var rlnIdentifier RLNIdentifier
 
 	copy(zkproof[:], proofBytes[0:proofOffset])
 	copy(proofRoot[:], proofBytes[proofOffset:rootOffset])
-	copy(epochR[:], proofBytes[rootOffset:epochOffset])
+	copy(externalNullifier[:], proofBytes[rootOffset:externalNullifierOffset])
-	copy(shareX[:], proofBytes[epochOffset:shareXOffset])
+	copy(shareX[:], proofBytes[externalNullifierOffset:shareXOffset])
 	copy(shareY[:], proofBytes[shareXOffset:shareYOffset])
 	copy(nullifier[:], proofBytes[shareYOffset:nullifierOffset])
-	copy(rlnIdentifier[:], proofBytes[nullifierOffset:rlnIdentifierOffset])
 
 	return &RateLimitProof{
 		Proof:             zkproof,
 		MerkleRoot:        proofRoot,
-		Epoch:         epochR,
+		ExternalNullifier: externalNullifier,
 		ShareX:            shareX,
 		ShareY:            shareY,
 		Nullifier:         nullifier,
-		RLNIdentifier: rlnIdentifier,
 	}, nil
 }
 
@@ -248,6 +270,8 @@ func (r *RLN) GenerateProof(data []byte, key IdentityCredential, index Membershi
 // input [ id_secret_hash<32> | num_elements<8> | path_elements<var1> | num_indexes<8> | path_indexes<var2> | x<32> | epoch<32> | rln_identifier<32> ]
 // output [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]
 func (r *RLN) GenerateRLNProofWithWitness(witness RLNWitnessInput) (*RateLimitProof, error) {
+	// TODO: Will be implemented once custom witness is supported in RLN v2
+	return nil, errors.New("not implemented")
 
 	proofBytes, err := r.w.GenerateRLNProofWithWitness(witness.serialize())
 	if err != nil {
@@ -284,11 +308,9 @@ func (r *RLN) GenerateRLNProofWithWitness(witness RLNWitnessInput) (*RateLimitPr
 	return &RateLimitProof{
 		Proof:      zkproof,
 		MerkleRoot: proofRoot,
-		Epoch:         epochR,
 		ShareX:     shareX,
 		ShareY:     shareY,
 		Nullifier:  nullifier,
-		RLNIdentifier: rlnIdentifier,
 	}, nil
 
 }
@@ -368,9 +390,17 @@ func (r *RLN) RecoverIDSecret(proof1 RateLimitProof, proof2 RateLimitProof) (IDS
 	return result, nil
 }
 
-// InsertMember adds the member to the tree
+// InsertMember adds the member to the tree. The leaf is made of
-func (r *RLN) InsertMember(idComm IDCommitment) error {
+// the id commitment and the user message limit
-	insertionSuccess := r.w.SetNextLeaf(idComm[:])
+func (r *RLN) InsertMember(idComm IDCommitment, userMessageLimit uint32) error {
+	userMessageLimitBytes := SerializeUint32(userMessageLimit)
+
+	hashedLeaf, err := r.Poseidon(idComm[:], userMessageLimitBytes[:])
+	if err != nil {
+		return err
+	}
+
+	insertionSuccess := r.w.SetNextLeaf(hashedLeaf[:])
 	if !insertionSuccess {
 		return errors.New("could not insert member")
 	}
@@ -476,9 +506,9 @@ func (r *RLN) GetMerkleProof(index MembershipIndex) (MerkleProof, error) {
 }
 
 // AddAll adds members to the Merkle tree
-func (r *RLN) AddAll(list []IDCommitment) error {
+func (r *RLN) AddAll(list []IdentityCredential) error {
 	for _, member := range list {
-		if err := r.InsertMember(member); err != nil {
+		if err := r.InsertMember(member.IDCommitment, member.UserMessageLimit); err != nil {
 			return err
 		}
 	}
@@ -520,7 +550,7 @@ func CreateMembershipList(n int) ([]IdentityCredential, MerkleNode, error) {
 		output = append(output, *keypair)
 
 		// insert the key to the Merkle tree
-		if err := rln.InsertMember(keypair.IDCommitment); err != nil {
+		if err := rln.InsertMember(keypair.IDCommitment, keypair.UserMessageLimit); err != nil {
 			return nil, MerkleNode{}, err
 		}
 	}

rln/rln_test.go

@@ -76,7 +76,7 @@ func (s *RLNSuite) TestInsertMember() {
 	keypair, err := rln.MembershipKeyGen()
 	s.NoError(err)
 
-	err = rln.InsertMember(keypair.IDCommitment)
+	err = rln.InsertMember(keypair.IDCommitment, keypair.UserMessageLimit)
 	s.NoError(err)
 }
 
@@ -105,7 +105,7 @@ func (s *RLNSuite) TestRemoveMember() {
 	keypair, err := rln.MembershipKeyGen()
 	s.NoError(err)
 
-	err = rln.InsertMember(keypair.IDCommitment)
+	err = rln.InsertMember(keypair.IDCommitment, keypair.UserMessageLimit)
 	s.NoError(err)
 
 	err = rln.DeleteMember(MembershipIndex(0))
@@ -123,7 +123,7 @@ func (s *RLNSuite) TestMerkleTreeConsistenceBetweenDeletionAndInsertion() {
 	keypair, err := rln.MembershipKeyGen()
 	s.NoError(err)
 
-	err = rln.InsertMember(keypair.IDCommitment)
+	err = rln.InsertMember(keypair.IDCommitment, keypair.UserMessageLimit)
 	s.NoError(err)
 
 	// read the Merkle Tree root after insertion
@@ -207,37 +207,64 @@ func (s *RLNSuite) TestCheckCorrectness() {
 	s.Equal(expectedRoot, root[:])
 }
 
+func (s *RLNSuite) TestGetLeaf() {
+	rln, err := NewRLN()
+	s.NoError(err)
+
+	amountLeafs := int(31)
+
+	for i := 0; i < amountLeafs; i++ {
+		// allowed messages per epoch of the membership
+		// using different values between 1 and 7
+		userMessageLimit := uint32(amountLeafs%7 + 1)
+
+		// generate membership
+		memKeys, err := rln.MembershipKeyGen(userMessageLimit)
+		s.NoError(err)
+
+		// insert membership
+		err = rln.InsertMember(memKeys.IDCommitment, memKeys.UserMessageLimit)
+		s.NoError(err)
+
+		// retrieve the leaf
+		retrievedLeaf, err := rln.GetLeaf(uint(i))
+		s.NoError(err)
+
+		// calculate the leaf we would expect
+		userMessageLimitBytes := SerializeUint32(userMessageLimit)
+		hashedLeaf, err := rln.Poseidon(memKeys.IDCommitment[:], userMessageLimitBytes[:])
+		s.NoError(err)
+
+		// assert it matches
+		s.Equal(hashedLeaf, retrievedLeaf)
+	}
+}
+
 func (s *RLNSuite) TestValidProof() {
 	rln, err := NewRLN()
 	s.NoError(err)
 
-	memKeys, err := rln.MembershipKeyGen()
+	// allowed messages per epoch of the membership
-	s.NoError(err)
+	userMessageLimit := uint32(10)
 
 	//peer's index in the Merkle Tree
 	index := uint(5)
 
+	memKeys, err := rln.MembershipKeyGen(userMessageLimit)
+	s.NoError(err)
+
 	// Create a Merkle tree with random members
 	for i := uint(0); i < 10; i++ {
 		if i == index {
-			// insert the current peer's pk
+			err = rln.InsertMember(memKeys.IDCommitment, memKeys.UserMessageLimit)
-			err = rln.InsertMember(memKeys.IDCommitment)
 			s.NoError(err)
-
-			fifthIndexLeaf, err := rln.GetLeaf(index)
-			s.NoError(err)
-			s.Equal(memKeys.IDCommitment, fifthIndexLeaf)
 		} else {
 			// create a new key pair
-			memberKeys, err := rln.MembershipKeyGen()
+			memberKeys, err := rln.MembershipKeyGen(userMessageLimit)
 			s.NoError(err)
 
-			err = rln.InsertMember(memberKeys.IDCommitment)
+			err = rln.InsertMember(memberKeys.IDCommitment, memberKeys.UserMessageLimit)
 			s.NoError(err)
-
-			leaf, err := rln.GetLeaf(i)
-			s.NoError(err)
-			s.Equal(memberKeys.IDCommitment, leaf)
 		}
 	}
 
@@ -245,10 +272,15 @@ func (s *RLNSuite) TestValidProof() {
 	msg := []byte("Hello")
 
 	// prepare the epoch
-	var epoch Epoch
+	var epoch Epoch = SerializeUint32(1000)
+
+	// generate multiple valid proofs for the same epoch
+	for i := uint32(0); i < userMessageLimit; i++ {
+		// message sequence within the epoch
+		messageId := uint32(i)
 
 		// generate proof
-	proofRes, err := rln.GenerateProof(msg, *memKeys, MembershipIndex(index), epoch)
+		proofRes, err := rln.GenerateProof(msg, *memKeys, MembershipIndex(index), epoch, messageId)
 		s.NoError(err)
 
 		// verify the proof
@@ -263,6 +295,52 @@ func (s *RLNSuite) TestValidProof() {
 		verified, err = rln.Verify(msg, *proofRes, root)
 		s.NoError(err)
 		s.True(verified)
+	}
+}
+
+func (s *RLNSuite) TestProofBeyondLimit() {
+	rln, err := NewRLN()
+	s.NoError(err)
+
+	// allowed messages per epoch of the membership
+	userMessageLimit := uint32(10)
+
+	//peer's index in the Merkle Tree
+	index := uint(5)
+
+	memKeys, err := rln.MembershipKeyGen(userMessageLimit)
+	s.NoError(err)
+
+	// Create a Merkle tree with random members
+	for i := uint(0); i < 10; i++ {
+		if i == index {
+			err = rln.InsertMember(memKeys.IDCommitment, memKeys.UserMessageLimit)
+			s.NoError(err)
+		} else {
+			// create a new key pair
+			memberKeys, err := rln.MembershipKeyGen(userMessageLimit)
+			s.NoError(err)
+
+			err = rln.InsertMember(memberKeys.IDCommitment, memberKeys.UserMessageLimit)
+			s.NoError(err)
+		}
+	}
+
+	// prepare the message
+	msg := []byte("Hello")
+
+	// prepare the epoch
+	var epoch Epoch = SerializeUint32(876543456)
+
+	// TODO;:
+	for i := uint32(userMessageLimit + 1); i < (userMessageLimit + 10); i++ {
+		// message sequence within the epoch
+		messageId := uint32(i)
+
+		// generate proof TODO:Errors!
+		_, err := rln.GenerateProof(msg, *memKeys, MembershipIndex(index), epoch, messageId)
+		s.Error(err)
+	}
 }
 
 func (s *RLNSuite) TestInvalidProof() {
@@ -279,14 +357,14 @@ func (s *RLNSuite) TestInvalidProof() {
 	for i := 0; i < 10; i++ {
 		if i == index {
 			// insert the current peer's pk
-			err := rln.InsertMember(memKeys.IDCommitment)
+			err := rln.InsertMember(memKeys.IDCommitment, memKeys.UserMessageLimit)
 			s.NoError(err)
 		} else {
 			// create a new key pair
 			memberKeys, err := rln.MembershipKeyGen()
 			s.NoError(err)
 
-			err = rln.InsertMember(memberKeys.IDCommitment)
+			err = rln.InsertMember(memberKeys.IDCommitment, memberKeys.UserMessageLimit)
 			s.NoError(err)
 		}
 	}
@@ -302,8 +380,11 @@ func (s *RLNSuite) TestInvalidProof() {
 
 	badIndex := 4
 
+	// message sequence within the epoch
+	messageId := uint32(1)
+
 	// generate proof
-	proofRes, err := rln.GenerateProof(msg, *memKeys, MembershipIndex(badIndex), epoch)
+	proofRes, err := rln.GenerateProof(msg, *memKeys, MembershipIndex(badIndex), epoch, messageId)
 	s.NoError(err)
 
 	// verify the proof (should not be verified)
@@ -351,6 +432,7 @@ func (s *RLNSuite) TestGetMerkleProof() {
 }
 
 func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesOK() {
+	s.T().Skip("Skipped until proof generation with witness is implemented for RLNv2")
 	treeSize := 20
 
 	rln, err := NewRLN()
@@ -363,7 +445,7 @@ func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesOK() {
 		memberKeys, err := rln.MembershipKeyGen()
 		s.NoError(err)
 
-		err = rln.InsertMember(memberKeys.IDCommitment)
+		err = rln.InsertMember(memberKeys.IDCommitment, memberKeys.UserMessageLimit)
 		s.NoError(err)
 		treeElements = append(treeElements, *memberKeys)
 	}
@@ -393,8 +475,11 @@ func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesOK() {
 		s.NoError(err)
 		s.True(verified1)
 
+		// message sequence within the epoch
+		messageId := uint32(1)
+
 		// Generate a proof without our custom witness, to ensure they match
-		proofRes2, err := rln.GenerateProof(message, treeElements[memberIndex], MembershipIndex(memberIndex), epoch)
+		proofRes2, err := rln.GenerateProof(message, treeElements[memberIndex], MembershipIndex(memberIndex), epoch, messageId)
 		s.NoError(err)
 
 		// Ensure we have the same root
@@ -403,15 +488,17 @@ func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesOK() {
 		// Proof generate with custom witness match the proof generate with the witness
 		// from zerokit. Proof itself is not asserted, can be different.
 		s.Equal(proofRes1.MerkleRoot, proofRes2.MerkleRoot)
-		s.Equal(proofRes1.Epoch, proofRes2.Epoch)
+		//s.Equal(proofRes1.Epoch, proofRes2.Epoch)
 		s.Equal(proofRes1.ShareX, proofRes2.ShareX)
 		s.Equal(proofRes1.ShareY, proofRes2.ShareY)
 		s.Equal(proofRes1.Nullifier, proofRes2.Nullifier)
-		s.Equal(proofRes1.RLNIdentifier, proofRes2.RLNIdentifier)
+		//s.Equal(proofRes1.RLNIdentifier, proofRes2.RLNIdentifier)
 	}
 }
 
 func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesNOK() {
+	s.T().Skip("Skipped until proof generation with witness is implemented for RLNv2")
+
 	treeSize := 20
 
 	rln, err := NewRLN()
@@ -424,7 +511,7 @@ func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesNOK() {
 		memberKeys, err := rln.MembershipKeyGen()
 		s.NoError(err)
 
-		err = rln.InsertMember(memberKeys.IDCommitment)
+		err = rln.InsertMember(memberKeys.IDCommitment, memberKeys.UserMessageLimit)
 		s.NoError(err)
 		treeElements = append(treeElements, *memberKeys)
 	}
@@ -457,7 +544,7 @@ func (s *RLNSuite) TestGenerateRLNProofWithWitness_VerifiesNOK() {
 		s.False(verified1)
 
 		// 2) Different epoch, does not verify
-		proofRes1.Epoch = ToEpoch(999)
+		//proofRes1.Epoch = ToEpoch(999)
 		verified2, err := rln.Verify(message, *proofRes1, root)
 		s.NoError(err)
 		s.False(verified2)

rln/serialize.go

@@ -8,18 +8,30 @@ import (
 )
 
 // serialize converts a RateLimitProof and the data to a byte seq
-// this conversion is used in the proofGen function
+// format taken from: https://github.com/vacp2p/zerokit/blob/v0.5.0/rln/src/public.rs#L747
-// the serialization is done as instructed in  https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L146
+// [identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-// [ id_key<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
+func serialize(
-func serialize(idKey IDSecretHash, memIndex MembershipIndex, epoch Epoch, msg []byte) []byte {
+	idKey IDSecretHash,
+	memIndex MembershipIndex,
+	userMessageLimit uint32,
+	messageId uint32,
+	externalNullifier [32]byte,
+	msg []byte) []byte {
 
 	memIndexBytes := make([]byte, 8)
 	binary.LittleEndian.PutUint64(memIndexBytes, uint64(memIndex))
 
 	lenPrefMsg := appendLength(msg)
 
+	var userMessageLimitByte [32]byte
+	var messageIdByte [32]byte
+	binary.LittleEndian.PutUint32(userMessageLimitByte[0:], userMessageLimit)
+	binary.LittleEndian.PutUint32(messageIdByte[0:], messageId)
+
 	output := append(idKey[:], memIndexBytes...)
-	output = append(output, epoch[:]...)
+	output = append(output, userMessageLimitByte[:]...)
+	output = append(output, messageIdByte[:]...)
+	output = append(output, externalNullifier[:]...)
 	output = append(output, lenPrefMsg...)
 
 	return output
@@ -28,7 +40,7 @@ func serialize(idKey IDSecretHash, memIndex MembershipIndex, epoch Epoch, msg []
 // serialize converts a RateLimitProof and data to a byte seq
 // this conversion is used in the proof verification proc
 // the order of serialization is based on https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L205
-// [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> | signal_len<8> | signal<var> ]
+// [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
 func (r RateLimitProof) serializeWithData(data []byte) []byte {
 	lenPrefMsg := appendLength(data)
 	proofBytes := r.serialize()
@@ -37,14 +49,13 @@ func (r RateLimitProof) serializeWithData(data []byte) []byte {
 }
 
 // serialize converts a RateLimitProof to a byte seq
-// [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32>
+// [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
 func (r RateLimitProof) serialize() []byte {
 	proofBytes := append(r.Proof[:], r.MerkleRoot[:]...)
-	proofBytes = append(proofBytes, r.Epoch[:]...)
+	proofBytes = append(proofBytes, r.ExternalNullifier[:]...)
 	proofBytes = append(proofBytes, r.ShareX[:]...)
 	proofBytes = append(proofBytes, r.ShareY[:]...)
 	proofBytes = append(proofBytes, r.Nullifier[:]...)
-	proofBytes = append(proofBytes, r.RLNIdentifier[:]...)
 	return proofBytes
 }
 

rln/types.go

@@ -36,12 +36,19 @@ type IdentityCredential = struct {
 	// Poseidon hash function implemented in rln lib
 	// more details in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Membership
 	IDCommitment IDCommitment `json:"idCommitment"`
+	// user's allowed messages per epoch, added in RLN v2
+	UserMessageLimit uint32 `json:"userMessageLimit"`
 }
 
 func IdentityCredentialEquals(i IdentityCredential, i2 IdentityCredential) bool {
-	return bytes.Equal(i.IDTrapdoor[:], i2.IDTrapdoor[:]) && bytes.Equal(i.IDNullifier[:], i2.IDNullifier[:]) && bytes.Equal(i.IDSecretHash[:], i2.IDSecretHash[:]) && bytes.Equal(i.IDCommitment[:], i2.IDCommitment[:])
+	return bytes.Equal(i.IDTrapdoor[:], i2.IDTrapdoor[:]) &&
+		bytes.Equal(i.IDNullifier[:], i2.IDNullifier[:]) &&
+		bytes.Equal(i.IDSecretHash[:], i2.IDSecretHash[:]) &&
+		bytes.Equal(i.IDCommitment[:], i2.IDCommitment[:]) &&
+		i.UserMessageLimit == i2.UserMessageLimit
 }
 
+// Equivalent plus proof: https://github.com/vacp2p/zerokit/blob/v0.5.0/rln/src/protocol.rs#L52
 type RateLimitProof struct {
 	// RateLimitProof holds the public inputs to rln circuit as
 	// defined in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Public-Inputs
@@ -50,7 +57,7 @@ type RateLimitProof struct {
 	// the root of Merkle tree used for the generation of the `proof`
 	MerkleRoot MerkleNode `json:"root"`
 	// the epoch used for the generation of the `proof`
-	Epoch Epoch `json:"epoch"`
+	ExternalNullifier Nullifier `json:"external_nullifier"`
 	// shareX and shareY are shares of user's identity key
 	// these shares are created using Shamir secret sharing scheme
 	// see details in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Linear-Equation-amp-SSS
@@ -59,8 +66,6 @@ type RateLimitProof struct {
 	// nullifier enables linking two messages published during the same epoch
 	// see details in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Nullifiers
 	Nullifier Nullifier `json:"nullifier"`
-	// Application specific RLN Identifier
-	RLNIdentifier RLNIdentifier `json:"rlnIdentifier"`
 }
 
 type MerkleProof struct {

rln/utils.go

@@ -1,6 +1,7 @@
 package rln
 
 import (
+	"encoding/binary"
 	"encoding/hex"
 	"hash"
 	"math/big"
@@ -181,3 +182,10 @@ func HashToBN255(data []byte) [32]byte {
 	copy(fixexLen[:], revert(frBN254Bytes[:]))
 	return fixexLen
 }
+
+func SerializeUint32(input uint32) [32]byte {
+	var byte32Type [32]byte
+	binary.LittleEndian.PutUint32(byte32Type[0:], input)
+
+	return byte32Type
+}