diff --git a/src/core/config/Categories.json b/src/core/config/Categories.json
index bebdd6a5..19ef01bc 100644
--- a/src/core/config/Categories.json
+++ b/src/core/config/Categories.json
@@ -74,7 +74,9 @@
             "CBOR Decode",
             "Caret/M-decode",
             "Rison Encode",
-            "Rison Decode"
+            "Rison Decode",
+            "Bytes to Long",
+            "Long to Bytes"
         ]
     },
     {
diff --git a/src/core/operations/BytesToLong.mjs b/src/core/operations/BytesToLong.mjs
new file mode 100644
index 00000000..cc8f281c
--- /dev/null
+++ b/src/core/operations/BytesToLong.mjs
@@ -0,0 +1,50 @@
+/**
+ * @author clubby789 [github.com/clubby789]
+ * @copyright Crown Copyright 2024
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+
+/**
+ * Bytes to Long Operation
+ */
+class BytesToLong extends Operation {
+
+    /**
+     * LongToBytes constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Bytes to Long";
+        this.module = "Default";
+        this.description = "Converts an array of bytes to a long integer. <br><br>e.g. <code>Hello</code> becomes <code>310939249775</code>";
+        this.inputType = "string";
+        this.outputType = "string";
+    }
+
+    /**
+     * @param {string} input
+     * @returns {string}
+     */
+    run(input, args) {
+        const bytes = [];
+        let charCode;
+
+        for (let i = 0; i < input.length; ++i) {
+            charCode = input.charCodeAt(i);
+            bytes.unshift(charCode & 0xFF);
+        }
+
+        let value = 0n;
+        for (let i = bytes.length - 1; i >= 0; i--) {
+            value = (value * 256n) + BigInt(bytes[i]);
+        }
+
+        return value.toString();
+    }
+
+}
+
+export default BytesToLong;
diff --git a/src/core/operations/LongToBytes.mjs b/src/core/operations/LongToBytes.mjs
new file mode 100644
index 00000000..5e9375e6
--- /dev/null
+++ b/src/core/operations/LongToBytes.mjs
@@ -0,0 +1,50 @@
+/**
+ * @author clubby789 [github.com/clubby789]
+ * @copyright Crown Copyright 2024
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+
+/**
+ * Long to Bytes Operation
+ */
+class LongToBytes extends Operation {
+
+    /**
+     * LongToBytes constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Long to Bytes";
+        this.module = "Default";
+        this.description = "Converts a long integer to an array of bytes. <br><br>e.g. <code>310939249775</code> becomes <code>Hello</code>";
+        this.inputType = "string";
+        this.outputType = "byteArray";
+        this.checks = [
+            {
+                pattern: "^[0-9]*$"
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @returns {byteArray}
+     */
+    run(input, args) {
+        const byteArray = [];
+        let long = BigInt(input.replace(/[^\d]/g, ""));
+        for (let index = 0; long > 0n; index ++) {
+            const byte = long & 0xffn;
+            byteArray.unshift(Number(byte));
+            long = (long - byte) / 256n ;
+        }
+
+        return byteArray;
+    }
+
+}
+
+export default LongToBytes;
diff --git a/tests/operations/index.mjs b/tests/operations/index.mjs
index 40ce7a2e..4cb0fb72 100644
--- a/tests/operations/index.mjs
+++ b/tests/operations/index.mjs
@@ -33,6 +33,7 @@ import "./tests/BLAKE2s.mjs";
 import "./tests/Bombe.mjs";
 import "./tests/BSON.mjs";
 import "./tests/ByteRepr.mjs";
+import "./tests/BytesLong.mjs";
 import "./tests/CaesarBoxCipher.mjs";
 import "./tests/CaretMdecode.mjs";
 import "./tests/CartesianProduct.mjs";
diff --git a/tests/operations/tests/BytesLong.mjs b/tests/operations/tests/BytesLong.mjs
new file mode 100644
index 00000000..b3bb500e
--- /dev/null
+++ b/tests/operations/tests/BytesLong.mjs
@@ -0,0 +1,34 @@
+/**
+ * BytesToLong/LongToBytes tests
+ *
+ * @author clubby789 [github.com/clubby789]
+ * @copyright Crown Copyright 2024
+ * @license Apache-2.0
+ */
+
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests([
+    {
+        name: "Bytes to Long",
+        input: "This is a testing string!",
+        expectedOutput: "529836718428447222471796396193323181240742300695594145834785",
+        recipeConfig: [
+            {
+                op: "Bytes to Long",
+                args: []
+            }
+        ],
+    },
+    {
+        name: "Long to Bytes",
+        input: "529836718428447222471796396193323181240742300695594145834785",
+        expectedOutput: "This is a testing string!",
+        recipeConfig: [
+            {
+                op: "Long to Bytes",
+                args: []
+            }
+        ],
+    }
+]);