diff --git a/src/core/operations/BytesToLong.mjs b/src/core/operations/BytesToLong.mjs
new file mode 100644
index 00000000..2c5b1262
--- /dev/null
+++ b/src/core/operations/BytesToLong.mjs
@@ -0,0 +1,52 @@
+/**
+ * @author clubby789 [github.com/clubby789]
+ * @copyright Crown Copyright 2020
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+
+/* global BigInt */
+
+/**
+ * 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 = BigInt(0);
+        for (let i = bytes.length - 1; i >= 0; i--) {
+            value = (value * BigInt(256)) + 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..898c5295
--- /dev/null
+++ b/src/core/operations/LongToBytes.mjs
@@ -0,0 +1,52 @@
+/**
+ * @author clubby789 [github.com/clubby789]
+ * @copyright Crown Copyright 2020
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+
+/* global BigInt */
+
+/**
+ * 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 > BigInt(0); index ++) {
+            const byte = long & BigInt(0xff);
+            byteArray.unshift(Number(byte));
+            long = (long - byte) / BigInt(256) ;
+        }
+
+        return byteArray;
+    }
+
+}
+
+export default LongToBytes;