Update folder structure

frontend/components/utilities/cryptography/aes-256-gcm.js

@@ -0,0 +1,63 @@
+/**
+ * @fileoverview Provides easy encryption/decryption methods using AES 256 GCM.
+ */
+
+"use strict";
+
+const crypto = require("crypto");
+
+const ALGORITHM = "aes-256-gcm";
+const BLOCK_SIZE_BYTES = 16; // 128 bit
+
+/**
+ * Provides easy encryption/decryption methods using AES 256 GCM.
+ */
+class Aes256Gcm {
+	/**
+	 * No need to run the constructor. The class only has static methods.
+	 */
+	constructor() {}
+
+	/**
+	 * Encrypts text with AES 256 GCM.
+	 * @param {string} text - Cleartext to encode.
+	 * @param {string} secret - Shared secret key, must be 32 bytes.
+	 * @returns {object}
+	 */
+	static encrypt(text, secret) {
+		const iv = crypto.randomBytes(BLOCK_SIZE_BYTES);
+		const cipher = crypto.createCipheriv(ALGORITHM, secret, iv);
+
+		let ciphertext = cipher.update(text, "utf8", "base64");
+		ciphertext += cipher.final("base64");
+		return {
+			ciphertext,
+			iv: iv.toString("base64"),
+			tag: cipher.getAuthTag().toString("base64"),
+		};
+	}
+
+	/**
+	 * Decrypts AES 256 CGM encrypted text.
+	 * @param {string} ciphertext - Base64-encoded ciphertext.
+	 * @param {string} iv - The base64-encoded initialization vector.
+	 * @param {string} tag - The base64-encoded authentication tag generated by getAuthTag().
+	 * @param {string} secret - Shared secret key, must be 32 bytes.
+	 * @returns {string}
+	 */
+	static decrypt(ciphertext, iv, tag, secret) {
+		const decipher = crypto.createDecipheriv(
+			ALGORITHM,
+			secret,
+			Buffer.from(iv, "base64")
+		);
+		decipher.setAuthTag(Buffer.from(tag, "base64"));
+
+		let cleartext = decipher.update(ciphertext, "base64", "utf8");
+		cleartext += decipher.final("utf8");
+
+		return cleartext;
+	}
+}
+
+module.exports = Aes256Gcm;