Add new operations: AES Key Wrap/Unwrap With Padding

src/core/config/Categories.json

@@ -155,6 +155,8 @@
             "Citrix CTX1 Decode",
             "AES Key Wrap",
             "AES Key Unwrap",
+            "AES Key Wrap With Padding",
+            "AES Key Unwrap With Padding",
             "Pseudo-Random Number Generator",
             "Enigma",
             "Bombe",

src/core/lib/AESKeyWrap.mjs

@@ -0,0 +1,99 @@
+/**
+ * AES Key Wrap/Unwrap defined in RFC 3394
+ *
+ * @author aosterhage [[email protected]]
+ * @copyright Crown Copyright 2025
+ * @license Apache-2.0
+ */
+
+import Utils from "../Utils.mjs";
+import forge from "node-forge";
+
+/**
+ * AES Key Wrap algorithm defined in RFC 3394.
+ *
+ * @param {string} plaintext
+ * @param {string} kek
+ * @param {string} iv
+ * @returns {string} ciphertext
+ */
+export function aesKeyWrap(plaintext, kek, iv) {
+    const cipher = forge.cipher.createCipher("AES-ECB", kek);
+
+    let A = iv;
+    const R = [];
+    for (let i = 0; i < plaintext.length; i += 8) {
+        R.push(plaintext.substring(i, i + 8));
+    }
+    let cntLower = 1, cntUpper = 0;
+    for (let j = 0; j < 6; j++) {
+        for (let i = 0; i < R.length; i++) {
+            cipher.start();
+            cipher.update(forge.util.createBuffer(A + R[i]));
+            cipher.finish();
+            const B = cipher.output.getBytes();
+            const msbBuffer = Utils.strToArrayBuffer(B.substring(0, 8));
+            const msbView = new DataView(msbBuffer);
+            msbView.setUint32(0, msbView.getUint32(0) ^ cntUpper);
+            msbView.setUint32(4, msbView.getUint32(4) ^ cntLower);
+            A = Utils.arrayBufferToStr(msbBuffer, false);
+            R[i] = B.substring(8, 16);
+            cntLower++;
+            if (cntLower > 0xffffffff) {
+                cntUpper++;
+                cntLower = 0;
+            }
+        }
+    }
+
+    return A + R.join("");
+}
+
+/**
+ * AES Key Unwrap algorithm defined in RFC 3394.
+ *
+ * @param {string} ciphertext
+ * @param {string} kek
+ * @returns {[string, string]} [plaintext, iv]
+ */
+export function aesKeyUnwrap(ciphertext, kek) {
+    const cipher = forge.cipher.createCipher("AES-ECB", kek);
+    cipher.start();
+    cipher.update(forge.util.createBuffer(""));
+    cipher.finish();
+    const paddingBlock = cipher.output.getBytes();
+
+    const decipher = forge.cipher.createDecipher("AES-ECB", kek);
+
+    let A = ciphertext.substring(0, 8);
+    const R = [];
+    for (let i = 8; i < ciphertext.length; i += 8) {
+        R.push(ciphertext.substring(i, i + 8));
+    }
+    let cntLower = R.length >>> 0;
+    let cntUpper = (R.length / ((1 << 30) * 4)) >>> 0;
+    cntUpper = cntUpper * 6 + ((cntLower * 6 / ((1 << 30) * 4)) >>> 0);
+    cntLower = cntLower * 6 >>> 0;
+    for (let j = 5; j >= 0; j--) {
+        for (let i = R.length - 1; i >= 0; i--) {
+            const aBuffer = Utils.strToArrayBuffer(A);
+            const aView = new DataView(aBuffer);
+            aView.setUint32(0, aView.getUint32(0) ^ cntUpper);
+            aView.setUint32(4, aView.getUint32(4) ^ cntLower);
+            A = Utils.arrayBufferToStr(aBuffer, false);
+            decipher.start();
+            decipher.update(forge.util.createBuffer(A + R[i] + paddingBlock));
+            decipher.finish();
+            const B = decipher.output.getBytes();
+            A = B.substring(0, 8);
+            R[i] = B.substring(8, 16);
+            cntLower--;
+            if (cntLower < 0) {
+                cntUpper--;
+                cntLower = 0xffffffff;
+            }
+        }
+    }
+
+    return [R.join(""), A];
+}

src/core/operations/AESKeyUnwrap.mjs

@@ -5,10 +5,10 @@
  */
 
 import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
 import Utils from "../Utils.mjs";
+import { aesKeyUnwrap } from "../lib/AESKeyWrap.mjs";
 import { toHexFast } from "../lib/Hex.mjs";
-import forge from "node-forge";
-import OperationError from "../errors/OperationError.mjs";
 
 /**
  * AES Key Unwrap operation
@@ -75,52 +75,13 @@ class AESKeyUnwrap extends Operation {
             throw new OperationError("input must be 8n (n>=3) bytes (currently " + inputData.length + " bytes)");
         }
 
-        const cipher = forge.cipher.createCipher("AES-ECB", kek);
-        cipher.start();
-        cipher.update(forge.util.createBuffer(""));
-        cipher.finish();
-        const paddingBlock = cipher.output.getBytes();
-
-        const decipher = forge.cipher.createDecipher("AES-ECB", kek);
+        const [output, outputIv] = aesKeyUnwrap(inputData, kek);
 
-        let A = inputData.substring(0, 8);
-        const R = [];
-        for (let i = 8; i < inputData.length; i += 8) {
-            R.push(inputData.substring(i, i + 8));
-        }
-        let cntLower = R.length >>> 0;
-        let cntUpper = (R.length / ((1 << 30) * 4)) >>> 0;
-        cntUpper = cntUpper * 6 + ((cntLower * 6 / ((1 << 30) * 4)) >>> 0);
-        cntLower = cntLower * 6 >>> 0;
-        for (let j = 5; j >= 0; j--) {
-            for (let i = R.length - 1; i >= 0; i--) {
-                const aBuffer = Utils.strToArrayBuffer(A);
-                const aView = new DataView(aBuffer);
-                aView.setUint32(0, aView.getUint32(0) ^ cntUpper);
-                aView.setUint32(4, aView.getUint32(4) ^ cntLower);
-                A = Utils.arrayBufferToStr(aBuffer, false);
-                decipher.start();
-                decipher.update(forge.util.createBuffer(A + R[i] + paddingBlock));
-                decipher.finish();
-                const B = decipher.output.getBytes();
-                A = B.substring(0, 8);
-                R[i] = B.substring(8, 16);
-                cntLower--;
-                if (cntLower < 0) {
-                    cntUpper--;
-                    cntLower = 0xffffffff;
-                }
-            }
-        }
-        if (A !== iv) {
+        if (outputIv !== iv) {
             throw new OperationError("IV mismatch");
         }
-        const P = R.join("");
 
-        if (outputType === "Hex") {
-            return toHexFast(Utils.strToArrayBuffer(P));
-        }
-        return P;
+        return outputType === "Hex" ? toHexFast(Utils.strToArrayBuffer(output)) : output;
     }
 
 }

src/core/operations/AESKeyUnwrapWithPadding.mjs

@@ -0,0 +1,98 @@
+/**
+ * @author aosterhage [[email protected]]
+ * @copyright Crown Copyright 2025
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Utils from "../Utils.mjs";
+import forge from "node-forge";
+import { aesKeyUnwrap } from "../lib/AESKeyWrap.mjs";
+import { toHexFast } from "../lib/Hex.mjs";
+
+/**
+ * AES Key Unwrap With Padding operation
+ */
+class AESKeyUnwrapWithPadding extends Operation {
+
+    /**
+     * AESKeyUnwrapWithPadding constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "AES Key Unwrap With Padding";
+        this.module = "Ciphers";
+        this.description = "Decryptor for a key wrapping algorithm defined in RFC 3394 combined with a padding convention defined in RFC 5649.";
+        this.infoURL = "https://wikipedia.org/wiki/Key_wrap";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                "name": "Key (KEK)",
+                "type": "toggleString",
+                "value": "",
+                "toggleValues": ["Hex", "UTF8", "Latin1", "Base64"]
+            },
+            {
+                "name": "Input",
+                "type": "option",
+                "value": ["Hex", "Raw"]
+            },
+            {
+                "name": "Output",
+                "type": "option",
+                "value": ["Hex", "Raw"]
+            },
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const kek = Utils.convertToByteString(args[0].string, args[0].option),
+            inputType = args[1],
+            outputType = args[2];
+
+        if (kek.length !== 16 && kek.length !== 24 && kek.length !== 32) {
+            throw new OperationError("KEK must be either 16, 24, or 32 bytes (currently " + kek.length + " bytes)");
+        }
+
+        input = Utils.convertToByteString(input, inputType);
+        if (input.length % 8 !== 0 || input.length < 16) {
+            throw new OperationError("input must be 8n (n>=2) bytes (currently " + input.length + " bytes)");
+        }
+
+        const decipher = forge.cipher.createDecipher("AES-ECB", kek);
+        let output, aiv;
+
+        if (input.length === 16) {
+            // Special case where the unwrapped data is one 64-bit block.
+            decipher.start();
+            decipher.update(forge.util.createBuffer(input));
+            decipher.finish();
+            output = decipher.output.getBytes();
+            aiv = output.substring(0, 8);
+            output = output.substring(8, 16);
+        } else {
+            // Otherwise, follow the unwrapping process from RFC 3394 (AESKeyUnwrap operation).
+            [output, aiv] = aesKeyUnwrap(input, kek);
+        }
+
+        // Get the unpadded length from the AIV (which is the MLI). Remove the padding from the output.
+        const unpaddedLength = Utils.byteArrayToInt(Utils.strToByteArray(aiv.substring(4, 8)), "big");
+        if (aiv.substring(0, 4) !== "\xa6\x59\x59\xa6" || unpaddedLength > output.length) {
+            throw new OperationError("invalid AIV found");
+        }
+        output = output.substring(0, unpaddedLength);
+
+        return outputType === "Hex" ? toHexFast(Utils.strToArrayBuffer(output)) : output;
+    }
+
+}
+
+export default AESKeyUnwrapWithPadding;

src/core/operations/AESKeyWrap.mjs

@@ -5,10 +5,10 @@
  */
 
 import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
 import Utils from "../Utils.mjs";
+import { aesKeyWrap } from "../lib/AESKeyWrap.mjs";
 import { toHexFast } from "../lib/Hex.mjs";
-import forge from "node-forge";
-import OperationError from "../errors/OperationError.mjs";
 
 /**
  * AES Key Wrap operation
@@ -70,44 +70,15 @@ class AESKeyWrap extends Operation {
         if (iv.length !== 8) {
             throw new OperationError("IV must be 8 bytes (currently " + iv.length + " bytes)");
         }
+
         const inputData = Utils.convertToByteString(input, inputType);
         if (inputData.length % 8 !== 0 || inputData.length < 16) {
             throw new OperationError("input must be 8n (n>=2) bytes (currently " + inputData.length + " bytes)");
         }
 
-        const cipher = forge.cipher.createCipher("AES-ECB", kek);
+        const output = aesKeyWrap(inputData, kek, iv);
 
-        let A = iv;
-        const R = [];
-        for (let i = 0; i < inputData.length; i += 8) {
-            R.push(inputData.substring(i, i + 8));
-        }
-        let cntLower = 1, cntUpper = 0;
-        for (let j = 0; j < 6; j++) {
-            for (let i = 0; i < R.length; i++) {
-                cipher.start();
-                cipher.update(forge.util.createBuffer(A + R[i]));
-                cipher.finish();
-                const B = cipher.output.getBytes();
-                const msbBuffer = Utils.strToArrayBuffer(B.substring(0, 8));
-                const msbView = new DataView(msbBuffer);
-                msbView.setUint32(0, msbView.getUint32(0) ^ cntUpper);
-                msbView.setUint32(4, msbView.getUint32(4) ^ cntLower);
-                A = Utils.arrayBufferToStr(msbBuffer, false);
-                R[i] = B.substring(8, 16);
-                cntLower++;
-                if (cntLower > 0xffffffff) {
-                    cntUpper++;
-                    cntLower = 0;
-                }
-            }
-        }
-        const C = A + R.join("");
-
-        if (outputType === "Hex") {
-            return toHexFast(Utils.strToArrayBuffer(C));
-        }
-        return C;
+        return outputType === "Hex" ? toHexFast(Utils.strToArrayBuffer(output)) : output;
     }
 
 }