Persisting rln credentials (#1037)

* Persisting Credentials implemented by writing json of keypair and rlnindex to files

* Removing testing files and ignores

* Update waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

Co-authored-by: Daniel Kaiser <git@kais3r.de>

* Update waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

Co-authored-by: Daniel Kaiser <git@kais3r.de>

* Comments

* Comments

* Security warning in comments

* Redundant echos. Omitting unused variables.

* Update waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

Co-authored-by: Hanno Cornelius <68783915+jm-clius@users.noreply.github.com>

* Limit line lengths using line breaks and indents

* Membership file paths declared as const

* Const fix

* Rln Credentials Merged.
Reading credentials from file abstracted away.

* Spaces

* Spaces

* Dangling constants removed. Comments position.

* Import sequence.

* Path as argument to readPersistentKeys.
Spaces in comments

* readPersistentKeys test

* Debug and info

* Index check in test

* Update tests/v2/test_waku_rln_relay.nim

Co-authored-by: G. <28568419+s1fr0@users.noreply.github.com>

* Abstracted writeRlnCredentials.
Fix var name in test.

* Usage of writeRlnCredentials in test

* Dnsclient?

* Test reverted to direct call to writeFile.
Abstrated writePersistentRlnCredentials usage causing error,
with readPersistentRlnCredentials

* Indentation

* Revert "Dnsclient?"

This reverts commit 3f4dba1a0b.

* Reverting abstraction of writing..
..persiting credential

Co-authored-by: Daniel Kaiser <git@kais3r.de>
Co-authored-by: Keshav Gupta <keshav.pg@hotmail.com>
Co-authored-by: Hanno Cornelius <68783915+jm-clius@users.noreply.github.com>
Co-authored-by: G. <28568419+s1fr0@users.noreply.github.com>

.gitignore

@@ -37,3 +37,5 @@ node_modules/
 
 # Ignore Jetbrains IDE files
 .idea/
+rlnCredentials.txt
+testPath.txt

tests/v2/test_waku_rln_relay.nim

@@ -6,6 +6,7 @@ import
   testutils/unittests, chronos, chronicles, stint,
   stew/byteutils, stew/shims/net as stewNet,
   libp2p/crypto/crypto,
+  json,
   ../../waku/v2/protocol/waku_rln_relay/[rln, waku_rln_relay_utils,
       waku_rln_relay_types],
   ../../waku/v2/node/wakunode2,
@@ -720,3 +721,39 @@ suite "Waku rln relay":
     # check that the conversion has not distorted the original value
     check:
       keypair.get().idCommitment == idCommitment
+
+  test "Read Persistent RLN credentials":
+    # create an RLN instance
+    var rlnInstance = createRLNInstance()
+    check:
+      rlnInstance.isOk == true
+
+    var key = membershipKeyGen(rlnInstance.value)
+    var empty: array[32, byte]
+    check:
+      key.isSome
+      key.get().idKey.len == 32
+      key.get().idCommitment.len == 32
+      key.get().idKey != empty
+      key.get().idCommitment != empty
+
+    debug "the generated membership key pair: ", key
+
+    let
+      k = key.get()
+      index =  MembershipIndex(1)
+
+    var rlnMembershipCredentials = RlnMembershipCredentials(membershipKeyPair: k, rlnIndex: index)
+
+    let path = "testPath.txt"
+
+    # Write RLN credentials
+    writeFile(path, pretty(%rlnMembershipCredentials))
+
+    var credentials = readPersistentRlnCredentials(path)
+
+    check:
+      credentials.membershipKeyPair == k
+      credentials.rlnIndex == index
+    
+

waku/v2/protocol/waku_rln_relay/waku_rln_relay_types.nim

@@ -38,6 +38,12 @@ type MembershipKeyPair* = object
   # more details in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Membership
   idCommitment*: IDCommitment
 
+type MembershipIndex* = uint
+
+type RlnMembershipCredentials* = object
+  membershipKeyPair*: MembershipKeyPair
+  rlnIndex*: MembershipIndex
+
 type RateLimitProof* = object
   ## RateLimitProof holds the public inputs to rln circuit as
   ## defined in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Public-Inputs
@@ -56,8 +62,6 @@ type RateLimitProof* = object
   ## see details in https://hackmd.io/tMTLMYmTR5eynw2lwK9n1w?view#Nullifiers
   nullifier*: Nullifier
 
-type MembershipIndex* = uint
-
 type ProofMetadata* = object
   nullifier*: Nullifier
   shareX*: MerkleNode
@@ -87,6 +91,10 @@ type WakuRLNRelay* = ref object
 type MessageValidationResult* {.pure.} = enum
   Valid, Invalid, Spam
 
+# RLN membership key and index files path
+const
+  RLN_CREDENTIALS_FILEPATH* = "rlnCredentials.txt"
+
 # inputs of the membership contract constructor
 # TODO may be able to make these constants private and put them inside the waku_rln_relay_utils
 const

waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

@@ -2,6 +2,8 @@
 
 import
   std/sequtils, tables, times,
+  std/streams,
+  std/os,
   chronicles, options, chronos, stint,
   confutils,
   web3, json,
@@ -741,7 +743,6 @@ proc mountRlnRelayStatic*(node: WakuNode,
   node.wakuRlnRelay = rlnPeer
 
 
-
 proc mountRlnRelayDynamic*(node: WakuNode,
                     ethClientAddr: string = "",
                     ethAccAddr: web3.Address,
@@ -788,9 +789,19 @@ proc mountRlnRelayDynamic*(node: WakuNode,
     else: # if no eth private key is available, skip registration
       debug "running waku-rln-relay in relay-only mode"
   else:
+    debug "Peer is already registered to the membership contract"
     keyPair = memKeyPair.get()
     rlnIndex = memIndex.get()
 
+  var
+    rlnMembershipCredentials = RlnMembershipCredentials(membershipKeyPair: keyPair, rlnIndex: rlnIndex)
+
+  # Since the files are stored as a raw text file, it is highly susceptible to theft.
+  # The files needs some encryption to resolve this.
+
+  # Write RLN credentials
+  writeFile(RLN_CREDENTIALS_FILEPATH, pretty(%rlnMembershipCredentials))
+
   # create the WakuRLNRelay
   var rlnPeer = WakuRLNRelay(membershipKeyPair: keyPair,
     membershipIndex: rlnIndex,
@@ -821,8 +832,21 @@ proc mountRlnRelayDynamic*(node: WakuNode,
 
   node.wakuRlnRelay = rlnPeer
 
+proc readPersistentRlnCredentials*(path: string) : RlnMembershipCredentials {.raises: [Defect, OSError, IOError, Exception].} =
+  info "Rln credentials exist in file"
+  # With regards to printing the keys, it is purely for debugging purposes so that the user becomes explicitly aware of the current keys in use when nwaku is started.
+  # Note that this is only until the RLN contract being used is the one deployed on Goerli testnet.
+  # These prints need to omitted once RLN contract is deployed on Ethereum mainnet and using valuable funds for staking.
       
-proc mountRlnRelay*(node: WakuNode, conf: WakuNodeConf|Chat2Conf, spamHandler: Option[SpamHandler] = none(SpamHandler)) {.raises: [Defect, ValueError, IOError, CatchableError].} =
+  let entireRlnCredentialsFile = readFile(path)
+
+  let jsonObject = parseJson(entireRlnCredentialsFile)
+  let deserializedRlnCredentials = to(jsonObject, RlnMembershipCredentials)
+  
+  debug "Deserialized Rln credentials", rlnCredentials=deserializedRlnCredentials
+  result = deserializedRlnCredentials
+
+proc mountRlnRelay*(node: WakuNode, conf: WakuNodeConf|Chat2Conf, spamHandler: Option[SpamHandler] = none(SpamHandler)) {.raises: [Defect, ValueError, IOError, CatchableError, Exception].} =
   if not conf.rlnRelayDynamic:
     info " setting up waku-rln-relay in on-chain mode... "
     # set up rln relay inputs
@@ -866,9 +890,18 @@ proc mountRlnRelay*(node: WakuNode, conf: WakuNodeConf|Chat2Conf, spamHandler: O
       let keyPair = @[(rlnRelayId, rlnRelayIdCommitmentKey)]
       let memKeyPair = keyPair.toMembershipKeyPairs()[0]
       # mount the rln relay protocol in the on-chain/dynamic mode
-      waitFor node.mountRlnRelayDynamic(memContractAddr = ethMemContractAddress, ethClientAddr = ethClientAddr, memKeyPair = some(memKeyPair), memIndex = some(rlnRelayIndex), ethAccAddr = ethAccountAddr,  ethAccountPrivKeyOpt = ethAccountPrivKeyOpt, pubsubTopic = conf.rlnRelayPubsubTopic, contentTopic = conf.rlnRelayContentTopic, spamHandler = spamHandler)
+      waitFor node.mountRlnRelayDynamic(memContractAddr = ethMemContractAddress, ethClientAddr = ethClientAddr,
+                memKeyPair = some(memKeyPair), memIndex = some(rlnRelayIndex), ethAccAddr = ethAccountAddr,
+                ethAccountPrivKeyOpt = ethAccountPrivKeyOpt, pubsubTopic = conf.rlnRelayPubsubTopic, contentTopic = conf.rlnRelayContentTopic, spamHandler = spamHandler)
+    elif fileExists(RLN_CREDENTIALS_FILEPATH):
+      var credentials = readPersistentRlnCredentials(RLN_CREDENTIALS_FILEPATH)
+      waitFor node.mountRlnRelayDynamic(memContractAddr = ethMemContractAddress, ethClientAddr = ethClientAddr,
+                memKeyPair = some(credentials.membershipKeyPair), memIndex = some(credentials.rlnIndex), ethAccAddr = ethAccountAddr,
+                ethAccountPrivKeyOpt = ethAccountPrivKeyOpt, pubsubTopic = conf.rlnRelayPubsubTopic, contentTopic = conf.rlnRelayContentTopic, spamHandler = spamHandler)
     else:
       # no rln credential is provided
       # mount the rln relay protocol in the on-chain/dynamic mode
-      waitFor node.mountRlnRelayDynamic(memContractAddr = ethMemContractAddress, ethClientAddr = ethClientAddr, ethAccAddr = ethAccountAddr, ethAccountPrivKeyOpt = ethAccountPrivKeyOpt, pubsubTopic = conf.rlnRelayPubsubTopic, contentTopic = conf.rlnRelayContentTopic, spamHandler = spamHandler)
-
+      info "no rln credential is provided"
+      waitFor node.mountRlnRelayDynamic(memContractAddr = ethMemContractAddress, ethClientAddr = ethClientAddr,
+                ethAccAddr = ethAccountAddr, ethAccountPrivKeyOpt = ethAccountPrivKeyOpt, pubsubTopic = conf.rlnRelayPubsubTopic,
+                contentTopic = conf.rlnRelayContentTopic, spamHandler = spamHandler)