#743 Fix Guardian ids in Lagrange Coefficients (#750)

* Initial attempt at fixing the problem (that works)

* Use sequence_order when announcing guardians

* Description of change

Author: lprichar

src/electionguard_gui/models/election_dto.py

@@ -105,6 +105,12 @@ def get_guardian_records(self) -> list[GuardianRecord]:
             raise Exception("No guardian records found")
         return from_list_raw(GuardianRecord, self.guardian_records)
 
+    def get_guardian_sequence_order(self, guardian_id: str) -> int:
+        for record in self.get_guardian_records():
+            if record.guardian_id == guardian_id:
+                return record.sequence_order
+        raise Exception("Guardian not found")
+
 
 def _get_list(election: dict[str, Any], name: str) -> list:
     value = election.get(name)

src/electionguard_gui/services/decryption_stages/decryption_s2_announce_service.py

@@ -30,6 +30,12 @@ def run(self, db: Database, decryption: DecryptionDto) -> None:
         decryption_shares = decryption.get_decryption_shares()
         for decryption_share_dict in decryption_shares:
             self._log.debug(f"announcing {decryption_share_dict.guardian_id}")
+            guardian_sequence_number = election.get_guardian_sequence_order(
+                decryption_share_dict.guardian_id
+            )
+            # coefficients will fail validation unless the key is a numeric encoded
+            #       string of the guardian's sequence number
+            decryption_share_dict.guardian_key.owner_id = str(guardian_sequence_number)
             decryption_mediator.announce(
                 decryption_share_dict.guardian_key,
                 decryption_share_dict.tally_share,