feat(nitro-verifier): add expiry-aware intermediate certificate caching (#240)

* feat(nitro-verifier): add expiry-aware intermediate certificate caching

Change trustedIntermediateCerts mapping from bytes32=>bool to
bytes32=>uint64, where the value is the certificate's notAfter timestamp
in seconds (0 = not cached). Cached certs are now automatically treated
as untrusted once block.timestamp exceeds their expiry, closing a
security gap where cached entries could outlive their X.509 validity.

Changes:
- INitroEnclaveVerifier.sol: Add certExpiries field to VerifierJournal
- NitroEnclaveVerifier.sol: uint64 mapping, expiry checks in
  _verifyJournal, checkTrustedIntermediateCerts, _cacheNewCert,
  revokeCert; constructor accepts parallel expiries array
- DeployRiscZeroStack.s.sol: Pass empty expiries array to constructor
- Tests: 6 new tests for expiry semantics, all existing tests updated
- Semver: 0.1.0 -> 0.2.0

CHAIN-3889

* refactor(nitro-verifier): remove redundant expiry == 0 checks since block.timestamp is always positive

* chore: regenerate semver-lock after expiry check simplification

Author: leopoldjoy

interfaces/multiproof/tee/INitroEnclaveVerifier.sol

@@ -61,6 +61,8 @@ struct VerifierJournal {
     uint64 timestamp;
     // Array of certificate hashes in the chain (root to leaf)
     bytes32[] certs;
+    // Certificate notAfter timestamps in seconds (one per cert, matching certs[] order)
+    uint64[] certExpiries;
     // User-defined data embedded in the attestation
     bytes userData;
     // Cryptographic nonce used for replay protection

scripts/multiproof/DeployRiscZeroStack.s.sol

@@ -125,15 +125,17 @@ contract DeployRiscZeroStack is Script {
             verifierId: nitroVerifierId, aggregatorId: bytes32(0), zkVerifier: risc0VerifierRouter
         });
 
-        // Start with an empty trusted certs array; certs will be auto-cached on first valid proof.
+        // Start with empty trusted certs and expiries arrays; certs will be auto-cached on first valid proof.
         bytes32[] memory trustedCerts = new bytes32[](0);
+        uint64[] memory trustedCertExpiries = new uint64[](0);
 
         // Use owner as placeholder proofSubmitter; must be updated to TEEProverRegistry
         // address after deployment via setProofSubmitter().
         NitroEnclaveVerifier nev = new NitroEnclaveVerifier(
             owner,
             NITRO_MAX_TIME_DIFF,
             trustedCerts,
+            trustedCertExpiries,
             nitroRootCert,
             owner,
             ZkCoProcessorType.RiscZero,

snapshots/abi/NitroEnclaveVerifier.json

@@ -16,6 +16,11 @@
         "name": "initializeTrustedCerts",
         "type": "bytes32[]"
       },
+      {
+        "internalType": "uint64[]",
+        "name": "initializeTrustedCertExpiries",
+        "type": "uint64[]"
+      },
       {
         "internalType": "bytes32",
         "name": "initialRootCert",
@@ -127,6 +132,11 @@
             "name": "certs",
             "type": "bytes32[]"
           },
+          {
+            "internalType": "uint64[]",
+            "name": "certExpiries",
+            "type": "uint64[]"
+          },
           {
             "internalType": "bytes",
             "name": "userData",
@@ -522,9 +532,9 @@
     "name": "trustedIntermediateCerts",
     "outputs": [
       {
-        "internalType": "bool",
+        "internalType": "uint64",
         "name": "",
-        "type": "bool"
+        "type": "uint64"
       }
     ],
     "stateMutability": "view",
@@ -613,6 +623,11 @@
             "name": "certs",
             "type": "bytes32[]"
           },
+          {
+            "internalType": "uint64[]",
+            "name": "certExpiries",
+            "type": "uint64[]"
+          },
           {
             "internalType": "bytes",
             "name": "userData",
@@ -1000,6 +1015,22 @@
     "name": "CallerNotProofSubmitter",
     "type": "error"
   },
+  {
+    "inputs": [
+      {
+        "internalType": "uint256",
+        "name": "certsLen",
+        "type": "uint256"
+      },
+      {
+        "internalType": "uint256",
+        "name": "expiriesLen",
+        "type": "uint256"
+      }
+    ],
+    "name": "CertExpiriesLengthMismatch",
+    "type": "error"
+  },
   {
     "inputs": [
       {

snapshots/semver-lock.json

@@ -236,11 +236,11 @@
     "sourceCodeHash": "0x032f11e23c188b939ba6cbdc446271b0caad2f4da00535b164a3489291162762"
   },
   "src/multiproof/tee/NitroEnclaveVerifier.sol:NitroEnclaveVerifier": {
-    "initCodeHash": "0x8cae758a4b1005bf2904e376fff49c2fb44e8d9d7bef1a33e18a85ee23d540a7",
-    "sourceCodeHash": "0x78d6c704d56ae8de255be71f5cc94e73e0bea1abd5b7e6dfcb4132174f89202b"
+    "initCodeHash": "0xac14e4b9130c476ba4ab77ecf70b36153921a9fe6ef3ab96c825aba8d9d18473",
+    "sourceCodeHash": "0x03614e89919c06e56e91b217702345edf74755c12c082475c4c742f45c201415"
   },
   "src/multiproof/tee/TEEProverRegistry.sol:TEEProverRegistry": {
-    "initCodeHash": "0x0ed3443601cd3b08c016dbe4a743fb6f1c1800d211e2edd739e588ed455783b1",
+    "initCodeHash": "0xfaec22f48eeef0f4ee0575b0e91028a1330fbf6faf52c2fce0f68b500a023970",
     "sourceCodeHash": "0xf1ec1f02f540da659a204b26acf986fdce7d7d63bba67a87923f52453fb92ccb"
   },
   "src/multiproof/tee/TEEVerifier.sol:TEEVerifier": {

snapshots/storageLayout/NitroEnclaveVerifier.json

@@ -18,7 +18,7 @@
     "label": "trustedIntermediateCerts",
     "offset": 0,
     "slot": "2",
-    "type": "mapping(bytes32 => bool)"
+    "type": "mapping(bytes32 => uint64)"
   },
   {
     "bytes": "8",

src/multiproof/tee/NitroEnclaveVerifier.sol

@@ -52,8 +52,8 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
     /// @dev Configuration mapping for each supported ZK coprocessor type
     mapping(ZkCoProcessorType => ZkCoProcessorConfig) public zkConfig;
 
-    /// @dev Mapping of trusted intermediate certificate hashes (excludes root certificate)
-    mapping(bytes32 => bool) public trustedIntermediateCerts;
+    /// @dev Mapping of trusted intermediate certificate hashes to their notAfter timestamps in seconds (0 = not cached)
+    mapping(bytes32 => uint64) public trustedIntermediateCerts;
 
     /// @dev Maximum allowed time difference in seconds for attestation timestamp validation
     uint64 public maxTimeDiff;
@@ -143,11 +143,15 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
     /// @dev Event emitted when the maximum time difference is updated
     event MaxTimeDiffUpdated(uint64 newMaxTimeDiff);
 
+    /// @dev Thrown when initializeTrustedCerts and initializeTrustedCertExpiries have different lengths
+    error CertExpiriesLengthMismatch(uint256 certsLen, uint256 expiriesLen);
+
     /**
      * @dev Initializes the contract with owner, time tolerance and initial trusted certificates
      * @param owner Address to be set as the contract owner
      * @param initialMaxTimeDiff Maximum time difference in seconds for timestamp validation
      * @param initializeTrustedCerts Array of initial trusted intermediate certificate hashes
+     * @param initializeTrustedCertExpiries Array of notAfter timestamps (seconds) for each initial cert
      * @param initialRootCert Hash of the AWS Nitro Enclave root certificate
      * @param initialProofSubmitter Address that is authorized to submit proofs
      * @param zkCoProcessor Type of ZK coprocessor to configure (RiscZero or Succinct)
@@ -158,16 +162,20 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
         address owner,
         uint64 initialMaxTimeDiff,
         bytes32[] memory initializeTrustedCerts,
+        uint64[] memory initializeTrustedCertExpiries,
         bytes32 initialRootCert,
         address initialProofSubmitter,
         ZkCoProcessorType zkCoProcessor,
         ZkCoProcessorConfig memory config,
         bytes32 verifierProofId
     ) {
         if (initialMaxTimeDiff == 0) revert ZeroMaxTimeDiff();
+        if (initializeTrustedCerts.length != initializeTrustedCertExpiries.length) {
+            revert CertExpiriesLengthMismatch(initializeTrustedCerts.length, initializeTrustedCertExpiries.length);
+        }
         maxTimeDiff = initialMaxTimeDiff;
         for (uint256 i = 0; i < initializeTrustedCerts.length; i++) {
-            trustedIntermediateCerts[initializeTrustedCerts[i]] = true;
+            trustedIntermediateCerts[initializeTrustedCerts[i]] = initializeTrustedCertExpiries[i];
         }
         _initializeOwner(owner);
         _setRootCert(initialRootCert);
@@ -239,7 +247,8 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
                 revert RootCertMismatch(rootCertHash, certs[0]);
             }
             for (uint256 j = 1; j < certs.length; j++) {
-                if (!trustedIntermediateCerts[certs[j]]) {
+                uint64 expiry = trustedIntermediateCerts[certs[j]];
+                if (block.timestamp > expiry) {
                     break;
                 }
                 trustedCertPrefixLen += 1;
@@ -319,7 +328,7 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
      * without affecting the root certificate or other trusted certificates.
      */
     function revokeCert(bytes32 certHash) external onlyOwner {
-        if (!trustedIntermediateCerts[certHash]) {
+        if (trustedIntermediateCerts[certHash] == 0) {
             revert CertificateNotFound(certHash);
         }
         delete trustedIntermediateCerts[certHash];
@@ -536,7 +545,7 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
     function _cacheNewCert(VerifierJournal memory journal) internal {
         for (uint256 i = journal.trustedCertsPrefixLen; i < journal.certs.length; i++) {
             bytes32 certHash = journal.certs[i];
-            trustedIntermediateCerts[certHash] = true;
+            trustedIntermediateCerts[certHash] = journal.certExpiries[i];
         }
     }
 
@@ -574,7 +583,8 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
                 }
                 continue;
             }
-            if (!trustedIntermediateCerts[certHash]) {
+            uint64 expiry = trustedIntermediateCerts[certHash];
+            if (block.timestamp > expiry) {
                 journal.result = VerificationResult.IntermediateCertsNotTrusted;
                 return journal;
             }
@@ -652,8 +662,8 @@ contract NitroEnclaveVerifier is Ownable, INitroEnclaveVerifier, ISemver {
     }
 
     /// @notice Semantic version.
-    /// @custom:semver 0.1.0
+    /// @custom:semver 0.2.0
     function version() public pure virtual returns (string memory) {
-        return "0.1.0";
+        return "0.2.0";
     }
 }