From 3e8c5d945cd65e920930ddd6dfb012123cd6a0a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <thomas@t-8ch.de>
Date: Mon, 27 Feb 2023 06:09:30 +0000
Subject: [PATCH] Add "XOR Checksum" operation

---
 src/core/config/Categories.json     |  3 +-
 src/core/operations/XORChecksum.mjs | 59 +++++++++++++++++++
 tests/operations/tests/Checksum.mjs | 90 ++++++++++++++++++++++++++++-
 3 files changed, 150 insertions(+), 2 deletions(-)
 create mode 100644 src/core/operations/XORChecksum.mjs

diff --git a/src/core/config/Categories.json b/src/core/config/Categories.json
index 075e8d66..97b20bd7 100644
--- a/src/core/config/Categories.json
+++ b/src/core/config/Categories.json
@@ -390,7 +390,8 @@
             "CRC-8 Checksum",
             "CRC-16 Checksum",
             "CRC-32 Checksum",
-            "TCP/IP Checksum"
+            "TCP/IP Checksum",
+            "XOR Checksum"
         ]
     },
     {
diff --git a/src/core/operations/XORChecksum.mjs b/src/core/operations/XORChecksum.mjs
new file mode 100644
index 00000000..1603a265
--- /dev/null
+++ b/src/core/operations/XORChecksum.mjs
@@ -0,0 +1,59 @@
+/**
+ * @author Thomas Weißschuh [thomas@t-8ch.de]
+ * @copyright Crown Copyright 2023
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import Utils from "../Utils.mjs";
+import { toHex } from "../lib/Hex.mjs";
+
+/**
+ * XOR Checksum operation
+ */
+class XORChecksum extends Operation {
+
+    /**
+     * XORChecksum constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "XOR Checksum";
+        this.module = "Crypto";
+        this.description = "XOR Checksum splits the input into blocks of a configurable size and performs the XOR operation on these blocks.";
+        this.infoURL = "https://wikipedia.org/wiki/XOR";
+        this.inputType = "ArrayBuffer";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Blocksize",
+                type: "number",
+                value: 4
+            },
+        ];
+    }
+
+    /**
+     * @param {ArrayBuffer} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const blocksize = args[0];
+        input = new Uint8Array(input);
+
+        const res = Array(blocksize);
+        res.fill(0);
+
+        for (const chunk of Utils.chunked(input, blocksize)) {
+            for (let i = 0; i < blocksize; i++) {
+                res[i] ^= chunk[i];
+            }
+        }
+
+        return toHex(res, "");
+    }
+}
+
+export default XORChecksum;
diff --git a/tests/operations/tests/Checksum.mjs b/tests/operations/tests/Checksum.mjs
index 142ee267..5266ab99 100644
--- a/tests/operations/tests/Checksum.mjs
+++ b/tests/operations/tests/Checksum.mjs
@@ -237,5 +237,93 @@ TestRegister.addTests([
                 "args": []
             }
         ]
-    }
+    },
+    {
+        name: "XOR Checksum (1): nothing",
+        input: "",
+        expectedOutput: "00",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [1]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (1): basic string",
+        input: BASIC_STRING,
+        expectedOutput: "08",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [1]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (1): UTF-8",
+        input: UTF8_STR,
+        expectedOutput: "df",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [1]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (1): all bytes",
+        input: ALL_BYTES,
+        expectedOutput: "00",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [1]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (4): nothing",
+        input: "",
+        expectedOutput: "00000000",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [4]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (4): basic string",
+        input: BASIC_STRING,
+        expectedOutput: "4918421b",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [4]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (4): UTF-8",
+        input: UTF8_STR,
+        expectedOutput: "83a424dc",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [4]
+            }
+        ]
+    },
+    {
+        name: "XOR Checksum (4): all bytes",
+        input: ALL_BYTES,
+        expectedOutput: "00000000",
+        recipeConfig: [
+            {
+                "op": "XOR Checksum",
+                "args": [4]
+            }
+        ]
+    },
 ]);