Rln relay key generation (#383)

* cleans up imported modules

* adds uploadContract proc and consolidates rln-relay test files

* deletes test_rln_relay_wrappers

* deletes wrappers tests

* adds waku_rln_relay_utils

* adds the unit test for the membership key generation

* adds the key generation procedure

* adds unit test of key gen proc

* removes extra spaces

* Update tests/v2/test_waku_rln_relay.nim

Co-authored-by: Oskar Thorén <ot@oskarthoren.com>

* deletes the newline

* adds rln to gitignore

Co-authored-by: Oskar Thorén <ot@oskarthoren.com>

.gitignore

@@ -28,3 +28,5 @@
 # Ignore simulation generated metrics files
 /metrics/prometheus
 /metrics/waku-sim-all-nodes-grafana-dashboard.json
+
+rln

tests/v2/test_waku_rln_relay.nim

@@ -2,7 +2,7 @@ import
   chronos, chronicles, options, stint, unittest,
   web3,
   stew/byteutils,
-  ../../waku/v2/protocol/waku_rln_relay/rln,
+  ../../waku/v2/protocol/waku_rln_relay/[rln, waku_rln_relay_utils],
   ../test_helpers,
   test_utils
 
@@ -206,4 +206,16 @@ suite "Waku rln relay":
       check:
         # the public and secret keys together are 64 bytes
         generatedKeys.len == 64
-      debug "generated keys: ", generatedKeys 
+      debug "generated keys: ", generatedKeys 
+      
+  test "membership Key Gen":
+    var key = membershipKeyGen()
+    var empty : array[32,byte]
+    check:
+      key.isSome
+      key.get().secretKey.len == 32
+      key.get().publicKey.len == 32
+      key.get().secretKey != empty
+      key.get().publicKey != empty
+    
+    debug "the generated membership key pair: ", key 

waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

@@ -0,0 +1,63 @@
+import 
+  chronicles, options, chronos, stint,
+  stew/byteutils,
+  rln 
+
+type MembershipKeyPair* = object 
+  secretKey*: array[32, byte]
+  publicKey*: array[32, byte]
+
+
+proc membershipKeyGen*(): Option[MembershipKeyPair] =
+  # generates a MembershipKeyPair that can be used for the registration into the rln membership contract
+  var 
+    merkleDepth: csize_t = 32
+    # parameters.key contains the parameters related to the Poseidon hasher
+    # to generate this file, clone this repo https://github.com/kilic/rln 
+    # and run the following command in the root directory of the cloned project
+    # cargo run --example export_test_keys
+    # the file is generated separately and copied here
+    parameters = readFile("waku/v2/protocol/waku_rln_relay/parameters.key")
+    pbytes = parameters.toBytes()
+    len : csize_t = uint(pbytes.len)
+    parametersBuffer = Buffer(`ptr`: unsafeAddr(pbytes[0]), len: len)
+
+  # check the parameters.key is not empty
+  if(pbytes.len == 0):
+    debug "error in parameters.key"
+    return none(MembershipKeyPair)
+    
+  # ctx holds the information that is going to be used for  the key generation
+  var 
+    obj = RLNBn256()
+    objPtr = unsafeAddr(obj)
+    ctx = objPtr
+  let res = newCircuitFromParams(merkleDepth, unsafeAddr parametersBuffer, ctx)
+
+  # check whether the circuit parameters are generated successfully
+  if(res == false):
+    debug "error in parameters generation"
+    return none(MembershipKeyPair)
+    
+  # keysBufferPtr will hold the generated key pairs i.e., secret and public keys 
+  var 
+    keysBufferPtr : Buffer
+    done = keyGen(ctx, keysBufferPtr) 
+
+  # check whether the keys are generated successfully
+  if(done == false):
+    debug "error in key generation"
+    return none(MembershipKeyPair)
+    
+  var generatedKeys = cast[ptr array[64, byte]](keysBufferPtr.`ptr`)[]
+  # the public and secret keys together are 64 bytes
+  if (generatedKeys.len != 64):
+    debug "the generated keys are invalid"
+    return none(MembershipKeyPair)
+  
+  var 
+    secret = cast[array[32, byte]](generatedKeys[0..31])
+    public = cast[array[32, byte]](generatedKeys[31..^1])
+    keypair = MembershipKeyPair(secretKey: secret, publicKey: public)
+
+  return some(keypair)