crypto.getRandomValues() method if available.-(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
+ },
+ {
+ "name": "Output",
+ "type": "option",
+ "value": ["Raw", "Hex", "Decimal"]
+ }
+ ];
+
+ // 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, outputType] = 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);
+
+ switch (outputType) {
+ case "Hex":
+ output.push(intValue.toString(16));
+ break;
+ case "Decimal":
+ output.push(intValue.toString(10));
+ break;
+ case "Raw":
+ default:
+ output.push(Utils.chr(intValue));
+ }
+ }
+
+ if (outputType === "Raw") {
+ return output.join("");
+ }
+ 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;
diff --git a/src/core/operations/RC6Decrypt.mjs b/src/core/operations/RC6Decrypt.mjs
new file mode 100644
index 0000000000..3185b6321f
--- /dev/null
+++ b/src/core/operations/RC6Decrypt.mjs
@@ -0,0 +1,119 @@
+/**
+ * @author Medjedtxm
+ * @copyright Crown Copyright 2026
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import Utils from "../Utils.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import { toHex } from "../lib/Hex.mjs";
+import { decryptRC6, getBlockSize, getDefaultRounds } from "../lib/RC6.mjs";
+
+/**
+ * RC6 Decrypt operation
+ */
+class RC6Decrypt extends Operation {
+
+ /**
+ * RC6Decrypt constructor
+ */
+ constructor() {
+ super();
+
+ this.name = "RC6 Decrypt";
+ this.module = "Ciphers";
+ this.description = "RC6 is a symmetric key block cipher derived from RC5. It was designed by Ron Rivest, Matt Robshaw, Ray Sidney, and Yiqun Lisa Yin to meet the requirements of the AES competition, and was one of the five finalists.