First Cryptochef branch commit.

src/core/operations/DecryptKeystoreFile.mjs

@@ -0,0 +1,140 @@
+/**
+ * Decrypts ETH keystore files, given the password.
+ *
+ * @author dgoldenberg [virtualcurrency@mitre.org]
+ * @copyright  MITRE 2023
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import JSSHA3 from "js-sha3";
+import Utils from "../Utils.mjs";
+import {fromHex} from "../lib/Hex.mjs";
+import scryptsy from "scryptsy";
+import { isWorkerEnvironment } from "../Utils.mjs";
+import forge from "node-forge";
+
+
+/**
+ * JPath expression operation
+*/
+class DecryptKeystoreFile extends Operation {
+
+    /**
+     * Decrypt Keystore constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Decrypt Keystore File";
+        this.module = "Crypto";
+        this.description = "Attempts to decrypt the given ETH keystore file, with the passed in password. Will return the private key if successful, error out if not.";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.infoURL = "https://github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition";
+        this.args = [
+            {
+                name: "password",
+                type: "string",
+                value: ""
+            },
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const password = args[0];
+        let jsonObj, dkey;
+        // We parse the JSON object first and throw an error if its not JSON.
+        try {
+            jsonObj = JSON.parse(input);
+        } catch (err) {
+            throw new OperationError(`Invalid input, not JSON. Data: ${err.message}`);
+        }
+
+        // We then check for a crypto property, and that crypto should have a kdf and kdfparams property.
+        if (!Object.prototype.hasOwnProperty.call(jsonObj, "crypto") || !Object.prototype.hasOwnProperty.call(jsonObj.crypto, "kdfparams") || !Object.prototype.hasOwnProperty.call(jsonObj.crypto, "kdf")) {
+            throw new OperationError(`Error. Invalid JSON blob, missing either a crypto, crypto.kdf or crypto.kdfparams object.`);
+        }
+        const kdfParams = jsonObj.crypto.kdfparams;
+        const kdfType = jsonObj.crypto.kdf;
+
+        // We compute the kdf.
+        if (kdfType === "scrypt") {
+            try {
+                // We compute the salt, and the compute the scrypt.
+                const salt = Buffer.from(Utils.convertToByteArray(kdfParams.salt, "hex"));
+                const data = scryptsy(password, salt, kdfParams.n,  kdfParams.r, kdfParams.p, kdfParams.dklen,
+                    p =>{
+                        if (isWorkerEnvironment()) self.sendStatusMessage(`Progress: ${p.percent.toFixed(0)}%`);
+                    });
+                // Result of the SCRYPT in hex.
+                dkey = data.toString("hex");
+            } catch (err) {
+                throw new OperationError("Error: " + err.toString());
+            }
+        } else if (kdfType === "pbkdf2") {
+            // If the kdf is PBKDF2, we check to make sure it has a prf property, and that property is hmac-sha256
+            if (!Object.prototype.hasOwnProperty.call(kdfParams, "prf") || kdfParams.prf !== "hmac-sha256") {
+                throw new OperationError(`Error with PBKDF2. Either HMAC function not present, or is not hmac-sha256. It is: ` + JSON.stringify(kdfParams));
+            }
+            // We compute the pbkdf2 and cast to hex.
+            const iterations = kdfParams.c;
+            const keyLength = kdfParams.dklen;
+            const salt = Utils.convertToByteString(kdfParams.salt, "hex");
+            dkey = forge.util.bytesToHex(forge.pkcs5.pbkdf2(password, salt, iterations, keyLength, "sha256"));
+
+        } else {
+            // If there's a different KDF, we err out.
+            throw new OperationError("We don't support KDF type " + kdfType + " ... yet.");
+        }
+
+        const mackey = dkey.slice(-32,);
+        const decryptionkey = dkey.slice(0, 32);
+        const ciphertext = jsonObj.crypto.ciphertext;
+        const hmac = jsonObj.crypto.mac;
+        const algo = JSSHA3.keccak256;
+
+        const testmac = algo(fromHex(mackey + ciphertext, "hex"));
+        if (testmac === hmac) {
+            // If the MAC passes, we can decrypt.
+            // We check for the right data to decrypt.
+            if (!Object.prototype.hasOwnProperty.call(jsonObj.crypto, "cipherparams") || !Object.prototype.hasOwnProperty.call(jsonObj.crypto.cipherparams, "iv")) {
+                throw new OperationError("We are missing needed cipherparams and IV.");
+            }
+            if (!Object.prototype.hasOwnProperty.call(jsonObj.crypto, "ciphertext") || !Object.prototype.hasOwnProperty.call(jsonObj.crypto.cipherparams, "iv")) {
+                throw new OperationError("We are the ciphertext");
+            }
+            // We grab the key, and IV, and ciphertext
+            const key = Utils.convertToByteString(decryptionkey, "hex");
+            const iv = Utils.convertToByteString(jsonObj.crypto.cipherparams.iv, "hex");
+            const cipherinput =  Utils.convertToByteString(jsonObj.crypto.ciphertext, "hex");
+            // We  create the decryptor.
+            const decipher = forge.cipher.createDecipher("AES-CTR", key);
+            // We do the decryption.
+            decipher.start({
+                iv: iv.length === 0 ? "" : iv,
+                tag:  undefined,
+                additionalData: undefined
+            });
+            decipher.update(forge.util.createBuffer(cipherinput));
+            const result = decipher.finish();
+            if (result) {
+                return decipher.output.toHex();
+            } else {
+                throw new OperationError("Unable to decrypt keystore with these parameters.");
+            }
+        } else {
+            // In this case the MAC failed so we error out.
+            throw new OperationError("MAC error. We got: " + testmac + " , but we wanted. " + hmac);
+        }
+    }
+
+}
+
+export default DecryptKeystoreFile;