From 7ad3992bd14e3f063a0b19fc7bba8ad2baf59c56 Mon Sep 17 00:00:00 2001
From: Matt <matt@artemisbot.uk>
Date: Tue, 7 Apr 2020 13:31:33 +0100
Subject: [PATCH] Add RSA Decrypt Operation

---
 src/core/operations/RSADecrypt.mjs | 86 ++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 src/core/operations/RSADecrypt.mjs

diff --git a/src/core/operations/RSADecrypt.mjs b/src/core/operations/RSADecrypt.mjs
new file mode 100644
index 00000000..0b0670e6
--- /dev/null
+++ b/src/core/operations/RSADecrypt.mjs
@@ -0,0 +1,86 @@
+/**
+ * @author Matt C [me@mitt.dev]
+ * @copyright Crown Copyright 2020
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import forge from "node-forge/dist/forge.min.js";
+import { MD_ALGORITHMS } from "../lib/RSA.mjs";
+
+/**
+ * RSA Decrypt operation
+ */
+class RSADecrypt extends Operation {
+
+    /**
+     * RSADecrypt constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "RSA Decrypt";
+        this.module = "Ciphers";
+        this.description = "Decrypt an RSA encrypted message with a PEM encoded private key.";
+        this.infoURL = "https://wikipedia.org/wiki/RSA_(cryptosystem)";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "RSA Private Key (PEM)",
+                type: "text",
+                value: "-----BEGIN RSA PRIVATE KEY-----"
+            },
+            {
+                name: "Key Password",
+                type: "text",
+                value: ""
+            },
+            {
+                name: "Encryption Scheme",
+                type: "argSelector",
+                value: [
+                    {
+                        name: "RSA-OAEP",
+                        on: [3]
+                    },
+                    {
+                        name: "RSAES-PKCS1-V1_5",
+                        off: [3]
+                    },
+                    {
+                        name: "RAW",
+                        off: [3]
+                    }]
+            },
+            {
+                name: "Message Digest Algorithm",
+                type: "option",
+                value: Object.keys(MD_ALGORITHMS)
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const [pemKey, password, scheme, md] = args;
+        if (pemKey.replace("-----BEGIN RSA PRIVATE KEY-----", "").length === 0) {
+            throw new OperationError("Please enter a private key.");
+        }
+        try {
+            const privKey = forge.pki.decryptRsaPrivateKey(pemKey, password);
+            const dMsg = privKey.decrypt(input, scheme, {md: MD_ALGORITHMS[md].create()});
+            return dMsg;
+        } catch (err) {
+            throw new OperationError(err);
+        }
+    }
+
+}
+
+export default RSADecrypt;