diff --git a/src/core/config/Categories.json b/src/core/config/Categories.json
index 434c8bb6..60bafdee 100644
--- a/src/core/config/Categories.json
+++ b/src/core/config/Categories.json
@@ -549,6 +549,7 @@
"P-list Viewer",
"Disassemble x86",
"Pseudo-Random Number Generator",
+ "Pseudo-Random Integer Generator",
"Generate De Bruijn Sequence",
"Generate UUID",
"Analyse UUID",
diff --git a/src/core/operations/PseudoRandomIntegerGenerator.mjs b/src/core/operations/PseudoRandomIntegerGenerator.mjs
new file mode 100644
index 00000000..209b0b41
--- /dev/null
+++ b/src/core/operations/PseudoRandomIntegerGenerator.mjs
@@ -0,0 +1,145 @@
+/**
+ * @author cktgh [chankaitung@gmail.com]
+ * @copyright Crown Copyright 2026
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import forge from "node-forge";
+import Utils, { isWorkerEnvironment } from "../Utils.mjs";
+import { DELIM_OPTIONS } from "../lib/Delim.mjs";
+
+/**
+ * Pseudo-Random Integer Generator operation
+ */
+class PseudoRandomIntegerGenerator extends Operation {
+
+ // in theory 2**53 is the max range, but we use Number.MAX_SAFE_INTEGER (2**53 - 1) as it is more consistent.
+ static MAX_RANGE = Number.MAX_SAFE_INTEGER;
+ // arbitrary choice
+ static BUFFER_SIZE = 1024;
+
+ /**
+ * PseudoRandomIntegerGenerator constructor
+ */
+ constructor() {
+ super();
+
+ this.name = "Pseudo-Random Integer Generator";
+ this.module = "Ciphers";
+ this.description = "A cryptographically-secure pseudo-random number generator (PRNG).
Generates random integers within a specified range using the browser's built-in crypto.getRandomValues() method if available.
The supported range of integers is from -(2^53 - 1) to (2^53 - 1).";
+ this.infoURL = "https://wikipedia.org/wiki/Pseudorandom_number_generator";
+ this.inputType = "string";
+ this.outputType = "string";
+ this.args = [
+ {
+ "name": "Number of Integers",
+ "type": "number",
+ "value": 1,
+ "min": 1
+ },
+ {
+ "name": "Min Value",
+ "type": "number",
+ "value": 0,
+ "min": Number.MIN_SAFE_INTEGER,
+ "max": Number.MAX_SAFE_INTEGER
+ },
+ {
+ "name": "Max Value",
+ "type": "number",
+ "value": 99,
+ "min": Number.MIN_SAFE_INTEGER,
+ "max": Number.MAX_SAFE_INTEGER
+ },
+ {
+ "name": "Delimiter",
+ "type": "option",
+ "value": DELIM_OPTIONS
+ }
+ ];
+
+ // not using BigUint64Array to avoid BigInt handling overhead
+ this.randomBuffer = new Uint32Array(PseudoRandomIntegerGenerator.BUFFER_SIZE);
+ this.randomBufferOffset = PseudoRandomIntegerGenerator.BUFFER_SIZE;
+ }
+
+ /**
+ * @param {string} input
+ * @param {Object[]} args
+ * @returns {string}
+ */
+ run(input, args) {
+ const [numInts, minInt, maxInt, delimiter] = args;
+
+ if (minInt === null || maxInt === null) return "";
+
+ const min = Math.ceil(minInt);
+ const max = Math.floor(maxInt);
+ const delim = Utils.charRep(delimiter || "Space");
+
+ if (!Number.isSafeInteger(min) || !Number.isSafeInteger(max)) {
+ throw new OperationError("Min and Max must be between `-(2^53 - 1)` and `2^53 - 1`.");
+ }
+ if (min > max) {
+ throw new OperationError("Min cannot be larger than Max.");
+ }
+ const range = max - min + 1; // inclusive range
+ if (range > PseudoRandomIntegerGenerator.MAX_RANGE) {
+ throw new OperationError("Range between Min and Max cannot be larger than `2^53`");
+ }
+
+ // as large as possible while divisible by range
+ const rejectionThreshold = PseudoRandomIntegerGenerator.MAX_RANGE - (PseudoRandomIntegerGenerator.MAX_RANGE % range);
+ const output = [];
+ for (let i = 0; i < numInts; i++) {
+ const result = this._generateRandomValue(rejectionThreshold);
+ const intValue = min + (result % range);
+ output.push(intValue.toString());
+ }
+
+ return output.join(delim);
+ }
+
+ /**
+ * Generate a random value, result will be less than the rejection threshold (exclusive).
+ *
+ * @param {number} rejectionThreshold
+ * @returns {number}
+ */
+ _generateRandomValue(rejectionThreshold) {
+ let result;
+ do {
+ if (this.randomBufferOffset + 2 > this.randomBuffer.length) {
+ this._resetRandomBuffer();
+ }
+ // stitching a 53 bit number; not using BigUint64Array to avoid BigInt handling overhead
+ result = (this.randomBuffer[this.randomBufferOffset++] & 0x1f_ffff) * 0x1_0000_0000 +
+ this.randomBuffer[this.randomBufferOffset++];
+ } while (result >= rejectionThreshold);
+
+ return result;
+ }
+
+ /**
+ * Fill random buffer with new random values and rseet the offset.
+ */
+ _resetRandomBuffer() {
+ if (isWorkerEnvironment() && self.crypto) {
+ self.crypto.getRandomValues(this.randomBuffer);
+ } else {
+ const bytes = forge.random.getBytesSync(this.randomBuffer.length * 4);
+ for (let j = 0; j < this.randomBuffer.length; j++) {
+ this.randomBuffer[j] = (bytes.charCodeAt(j * 4) << 24) |
+ (bytes.charCodeAt(j * 4 + 1) << 16) |
+ (bytes.charCodeAt(j * 4 + 2) << 8) |
+ bytes.charCodeAt(j * 4 + 3);
+ }
+ }
+ this.randomBufferOffset = 0;
+ }
+
+}
+
+export default PseudoRandomIntegerGenerator;