From 8cb1dce3fd33bca222aadcc2378bb692180a8677 Mon Sep 17 00:00:00 2001
From: Davy Van Roy <davy.van.roy@gmail.com>
Date: Fri, 30 Oct 2020 14:07:47 +0100
Subject: [PATCH] add salt to EIP712 domain (#1260)

* add salt to EIP-712 domain

* ran `gradlew spotlessApply`
---
 .../java/org/web3j/crypto/StructuredData.java |  9 ++++-
 .../web3j/crypto/StructuredDataEncoder.java   |  4 ++
 .../org/web3j/crypto/StructuredDataTest.java  | 15 +++++++
 .../ValidStructuredDataWithSalt.json          | 39 +++++++++++++++++++
 4 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 crypto/src/test/resources/structured_data_json_files/ValidStructuredDataWithSalt.json

diff --git a/crypto/src/main/java/org/web3j/crypto/StructuredData.java b/crypto/src/main/java/org/web3j/crypto/StructuredData.java
index 0dbf9e8db..ffe0e3c2f 100644
--- a/crypto/src/main/java/org/web3j/crypto/StructuredData.java
+++ b/crypto/src/main/java/org/web3j/crypto/StructuredData.java
@@ -48,17 +48,20 @@ static class EIP712Domain {
         private final String version;
         private final Uint256 chainId;
         private final Address verifyingContract;
+        private final String salt;
 
         @JsonCreator
         public EIP712Domain(
                 @JsonProperty(value = "name") String name,
                 @JsonProperty(value = "version") String version,
                 @JsonProperty(value = "chainId") Uint256 chainId,
-                @JsonProperty(value = "verifyingContract") Address verifyingContract) {
+                @JsonProperty(value = "verifyingContract") Address verifyingContract,
+                @JsonProperty(value = "salt") String salt) {
             this.name = name;
             this.version = version;
             this.chainId = chainId;
             this.verifyingContract = verifyingContract;
+            this.salt = salt;
         }
 
         public String getName() {
@@ -76,6 +79,10 @@ public Uint256 getChainId() {
         public Address getVerifyingContract() {
             return verifyingContract;
         }
+
+        public String getSalt() {
+            return salt;
+        }
     }
 
     static class EIP712Message {
diff --git a/crypto/src/main/java/org/web3j/crypto/StructuredDataEncoder.java b/crypto/src/main/java/org/web3j/crypto/StructuredDataEncoder.java
index be1beb4bb..66a3b0696 100644
--- a/crypto/src/main/java/org/web3j/crypto/StructuredDataEncoder.java
+++ b/crypto/src/main/java/org/web3j/crypto/StructuredDataEncoder.java
@@ -362,6 +362,10 @@ public byte[] hashDomain() throws RuntimeException {
         data.put(
                 "verifyingContract",
                 ((HashMap<String, Object>) data.get("verifyingContract")).get("value"));
+
+        if (data.get("salt") == null) {
+            data.remove("salt");
+        }
         return sha3(encodeData("EIP712Domain", data));
     }
 
diff --git a/crypto/src/test/java/org/web3j/crypto/StructuredDataTest.java b/crypto/src/test/java/org/web3j/crypto/StructuredDataTest.java
index dc7806ad9..34791eb5c 100644
--- a/crypto/src/test/java/org/web3j/crypto/StructuredDataTest.java
+++ b/crypto/src/test/java/org/web3j/crypto/StructuredDataTest.java
@@ -394,4 +394,19 @@ public void testDataNotPerfectArrayButDeclaredArrayInSchema()
                 new StructuredDataEncoder(getResource(invalidStructuredDataJSONFilePath));
         assertThrows(RuntimeException.class, dataEncoder::hashStructuredData);
     }
+
+    @Test
+    public void testHashDomainWithSalt() throws RuntimeException, IOException {
+        String validStructuredDataWithSaltJSONFilePath =
+                "build/resources/test/"
+                        + "structured_data_json_files/"
+                        + "ValidStructuredDataWithSalt.json";
+        StructuredDataEncoder dataEncoder =
+                new StructuredDataEncoder(getResource(validStructuredDataWithSaltJSONFilePath));
+        byte[] structHashDomain = dataEncoder.hashDomain();
+        String expectedDomainStructHash =
+                "0xbae4f6f7b9bfdfda060692099b0e1ccecd25d62b7c92cc9f3b907f33178b81e3";
+
+        assertEquals(Numeric.toHexString(structHashDomain), expectedDomainStructHash);
+    }
 }
diff --git a/crypto/src/test/resources/structured_data_json_files/ValidStructuredDataWithSalt.json b/crypto/src/test/resources/structured_data_json_files/ValidStructuredDataWithSalt.json
new file mode 100644
index 000000000..1a69d5c48
--- /dev/null
+++ b/crypto/src/test/resources/structured_data_json_files/ValidStructuredDataWithSalt.json
@@ -0,0 +1,39 @@
+{
+  "types": {
+    "EIP712Domain": [
+      {"name": "name", "type": "string"},
+      {"name": "version", "type": "string"},
+      {"name": "chainId", "type": "uint256"},
+      {"name": "verifyingContract", "type": "address"},
+      {"name": "salt", "type": "bytes32"}
+    ],
+    "Person": [
+      {"name": "name", "type": "string"},
+      {"name": "wallet", "type": "address"}
+    ],
+    "Mail": [
+      {"name": "from", "type": "Person"},
+      {"name": "to", "type": "Person"},
+      {"name": "contents", "type": "string"}
+    ]
+  },
+  "primaryType": "Mail",
+  "domain": {
+    "name": "Ether Mail",
+    "version": "1",
+    "chainId": 1,
+    "verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
+    "salt": "0xf2d857f4a3edcb9b78b4d503bfe733db1e3f6cdc2b7971ee739626c97e86a558"
+  },
+  "message": {
+    "from": {
+      "name": "Cow",
+      "wallet": "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"
+    },
+    "to": {
+      "name": "Bob",
+      "wallet": "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"
+    },
+    "contents": "Hello, Bob!"
+  }
+}