2 files changed, 36 insertions, 1 deletions
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/ISigner.sol b/packages/contracts/src/contracts/current/protocol/Exchange/ISigner.sol
new file mode 100644
index 000000000..7f8284c14
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/ISigner.sol
@@ -0,0 +1,28 @@
+/*
+
+  Copyright 2017 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.19;
+
+contract ISigner {
+    
+    function isValidSignature(
+        bytes32 hash,
+        bytes signature)
+        public view
+        returns (bool isValid);
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
index 8e5fbb22e..7edb5a372 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
@@ -19,6 +19,7 @@
 pragma solidity ^0.4.19;
 
 import "./mixins/MSignatureValidator.sol";
+import "./ISigner.sol";
 
 /// @dev Provides MSignatureValidator
 contract MixinSignatureValidator is
@@ -27,7 +28,8 @@ contract MixinSignatureValidator is
     enum SignatureType {
         Invalid,
         Caller,
-        Ecrecover
+        Ecrecover,
+        Contract
     }
   
     function isValidSignature(
@@ -68,6 +70,11 @@ contract MixinSignatureValidator is
             );
             isValid = signer == recovered;
             return;
+        
+        // Signature verified by signer contract
+        } else if (signatureType == SignatureType.Contract) {
+            isValid = ISigner(signer).isValidSignature(hash, signature);
+            return;
         }
         
         // Anything else is illegal (We do not return false because