From 93b2d59b96ea587bbe21d934cbe48d82a2981e97 Mon Sep 17 00:00:00 2001
From: danielsanchezq <sanchez.quiros.daniel@gmail.com>
Date: Thu, 21 Mar 2024 13:27:52 +0100
Subject: [PATCH] Add case in where verifier data is the same but column is
 different

---
 da/verifier.py | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/da/verifier.py b/da/verifier.py
index 46b4dbe..a9dae52 100644
--- a/da/verifier.py
+++ b/da/verifier.py
@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from hashlib import sha3_256
-from typing import List, Optional, Sequence, Set
+from typing import List, Optional, Sequence, Set, Dict
 
 from eth2spec.deneb.mainnet import BLSFieldElement
 from eth2spec.eip7594.mainnet import (
@@ -26,13 +26,16 @@ class DABlob:
     rows_commitments: List[Commitment]
     rows_proofs: List[Proof]
 
-    def id(self):
+    def id(self) -> bytes:
         return da.common.build_attestation_message(self.aggregated_column_commitment, self.rows_commitments)
 
+    def column_id(self) -> bytes:
+        return sha3_256(self.column.as_bytes()).digest()
+
 
 class DAVerifier:
     def __init__(self, sk: BLSPrivateKey):
-        self.attested_blobs: Set[bytes] = set()
+        self.attested_blobs: Dict[bytes, (bytes, Attestation)] = dict()
         self.sk = sk
 
     @staticmethod
@@ -84,8 +87,14 @@ class DAVerifier:
         return Attestation(signature=bls_pop.Sign(self.sk, message))
 
     def verify(self, blob: DABlob) -> Optional[Attestation]:
-        if (blob_id := blob.id()) in self.attested_blobs:
-            # We already attested for such blob, skip
+        blob_id = blob.id()
+        if previous_attestation := self.attested_blobs.get(blob_id):
+            column_id, attestation = previous_attestation
+            # we already attested, is cached so we return it
+            if column_id == blob.column_id():
+                return attestation
+            # we already attested and they are asking us to attest the same data different column
+            # skip
             return None
         is_column_verified = DAVerifier._verify_column(
             blob.column,
@@ -101,5 +110,6 @@ class DAVerifier:
         )
         if not are_chunks_verified:
             return
-        self.attested_blobs.add(blob_id)
-        return self._build_attestation(blob)
+        attestation = self._build_attestation(blob)
+        self.attested_blobs[blob_id] = (blob.column_id(), attestation)
+        return attestation