npm-package-nodejs-utils-lda/src/cjs/security/crypto.service.cjs

Este projeto tem como fins de criar e abstrair módulos basicos e utilidades para o node js

const forge = require('node-forge');
const crypto = require('crypto');
const { ensureRSAKeys } = require('./key-manager.service.cjs');

// Garante que as chaves existam antes de usar
const { privateKeyPem } = ensureRSAKeys();

// Converte PEM em objeto forge
const privateKey = forge.pki.privateKeyFromPem(privateKeyPem);

/**
 * Descriptografa a chave AES usando RSA-OAEP + SHA-256
 *
 * @param {string} encryptedKeyB64
 * @returns {Buffer}
 */
function decryptAESKey(encryptedKeyB64) {
	const encryptedBytes = forge.util.decode64(encryptedKeyB64);

	const decrypted = privateKey.decrypt(encryptedBytes, 'RSA-OAEP', {
		md: forge.md.sha256.create()
	});

	return Buffer.from(decrypted, 'binary');
}

/**
 * Descriptografa dados usando AES-256-GCM
 *
 * @param {string} encryptedDataB64
 * @param {Buffer} key
 * @param {string} ivB64
 * @param {string} authTagB64
 * @returns {string}
 */
function decryptAESGCM(encryptedDataB64, key, ivB64, authTagB64) {
	const encrypted = Buffer.from(encryptedDataB64, 'base64');
	const iv = Buffer.from(ivB64, 'base64');
	const authTag = Buffer.from(authTagB64, 'base64');

	const decipher = crypto.createDecipheriv('aes-256-gcm', key, iv);
	decipher.setAuthTag(authTag);

	let decrypted = decipher.update(encrypted, null, 'utf8');
	decrypted += decipher.final('utf8');

	return decrypted;
}

module.exports = {
	decryptAESKey,
	decryptAESGCM
};