First version of AdjudicatorAgent and Investigator actor. Closes #931

nucypher/blockchain/eth/actors.py

@@ -632,3 +632,25 @@ class PolicyAuthor(NucypherTokenActor):
         from nucypher.blockchain.eth.policies import BlockchainPolicy
         blockchain_policy = BlockchainPolicy(alice=self, *args, **kwargs)
         return blockchain_policy
+
+
+class Investigator(NucypherTokenActor):
+    """
+    Actor that reports incorrect CFrags to the Adjudicator contract.
+    In most cases, Bob will act as investigator, but the actor is generic enough than
+    anyone can report CFrags.
+    """
+
+    def __init__(self,
+                 checksum_address: str,
+                 *args, **kwargs) -> None:
+
+        super().__init__(checksum_address=checksum_address, *args, **kwargs)
+
+        self.adjudicator_agent = AdjudicatorAgent(blockchain=self.blockchain)
+
+    def request_evaluation(self, evidence):
+        receipt = self.adjudicator_agent.evaluate_cfrag(evidence=evidence,
+                                                        sender_address=self.checksum_address)
+        self._transaction_cache.append((datetime.utcnow(), receipt))
+        return receipt

nucypher/blockchain/eth/agents.py

@@ -499,46 +499,17 @@ class UserEscrowAgent(EthereumContractAgent):
 
 
 class AdjudicatorAgent(EthereumContractAgent, metaclass=Agency):
-    """TODO Issue #931"""
 
     registry_contract_name = "Adjudicator"
     _proxy_name = "Dispatcher"
 
-    def evaluate_cfrag(self,
-                       capsule_bytes: bytes,
-                       capsule_signature_by_requester: bytes,
-                       capsule_signature_by_requester_and_staker: bytes,
-                       cfrag_bytes: bytes,
-                       cfrag_signature_by_staker: bytes,
-                       requester_public_key: bytes,
-                       staker_public_key: bytes,
-                       staker_public_key_signature: bytes,
-                       precomputed_data: bytes):
+    def evaluate_cfrag(self, evidence, sender_address: str):
         """
-
-        From Contract Source:
-
-        function evaluateCFrag(
-            bytes memory _capsuleBytes,
-            bytes memory _capsuleSignatureByRequester,
-            bytes memory _capsuleSignatureByRequesterAndStaker,
-            bytes memory _cFragBytes,
-            bytes memory _cFragSignatureByStaker,
-            bytes memory _requesterPublicKey,
-            bytes memory _stakerPublicKey,
-            bytes memory _stakerPublicKeySignature,
-            bytes memory _preComputedData
-        )
-
-        :param capsule:
-        :param capsule_signature_by_requester:
-        :param capsule_signature_by_requester_and_staker:
-        :param cfrag:
-        :param cfrag_signature_by_staker:
-        :param requester_public_key:
-        :param staker_public_key:
-        :param staker_piblc_key_signature:
-        :param precomputed_data:
+        Submits proof that a worker created wrong CFrag
+        :param evidence:
+        :param sender_address:
         :return:
         """
-        # TODO: #931 - Challenge Agent and Actor - "Investigator"
+        contract_function = self.contract.functions.evaluateCFrag(evidence.evaluation_arguments())
+        receipt = self.blockchain.send_transaction(transaction_function=contract_function, sender_address=sender_address)
+        return receipt

nucypher/blockchain/eth/sol/source/contracts/Adjudicator.sol

@@ -72,15 +72,15 @@ contract Adjudicator is Upgradeable {
     }
 
     /**
-    * @notice Submit proof that staker created wrong CFrag
+    * @notice Submit proof that a worker created wrong CFrag
     * @param _capsuleBytes Serialized capsule
     * @param _cFragBytes Serialized CFrag
-    * @param _cFragSignature Signature of CFrag by staker
+    * @param _cFragSignature Signature of CFrag by worker
     * @param _taskSignature Signature of task specification by Bob
-    * @param _requesterPublicKey Requester's public key that was used to sign Capsule
-    * @param _workerPublicKey Staker's public key that was used to sign Capsule and CFrag
+    * @param _requesterPublicKey Bob's signing public key, also known as "stamp"
+    * @param _workerPublicKey Worker's signing public key, also known as "stamp"
     * @param _workerIdentityEvidence Signature of worker's public key by worker's eth-key
-    * @param _preComputedData Pre computed data for CFrag correctness verification
+    * @param _preComputedData Additional pre-computed data for CFrag correctness verification
     **/
     function evaluateCFrag(
         bytes memory _capsuleBytes,