keydb.js

var skynet = require('./skynet');
var crypto = require('./crypto');
var aes = require('aes-js');
var base64 = require('js-base64');
var buffer = require('buffer');

// check if the key already exists in the database referenced by skylink
// if not, append the key to the database
export async function appendKey(key, skylink, appId) {
	const database = await skynet.downloadText(skylink);
	if (!database) {
		throw new Error('Could not locate database');
	}
	const input = new Uint8Array(32);
	input.set(crypto.stringToUint8Array('{' + key + '}').slice(0, 32));
	const oldDB = base64.Base64.toUint8Array(
		database.text.slice(database.text.indexOf('{') + 1, database.text.indexOf('}'))
	);
	const aesKey = crypto.HashAll(crypto.encodeString(appId), crypto.encodeString(key));
	const aesEcb = new aes.ModeOfOperation.ecb(aesKey);
	const encrypted = aesEcb.encrypt(input);
	const newDB = new Uint8Array(oldDB.length + encrypted.length);
	newDB.set(oldDB);
	newDB.set(encrypted, oldDB.length);
	const newDatabase = '{' + base64.Base64.fromUint8Array(newDB) + '}';
	return await skynet.uploadText(newDatabase, database.name);
}

// update the registry with the new key
export async function appendRegistryKey(key, appId) {
	const seed = buffer.Buffer.from(crypto.HashDataKey(appId)).toString('hex');
	const {publicKey, privateKey} = crypto.keyPairFromSeed(seed);
	const entry = await skynet.getEntry(publicKey, appId);
	if (!entry) {
		const link = await skynet.uploadText('{}', 'db.txt');
		const newLink = await appendKey(key, link, appId);
		if (newLink == '') {
			return false;
		}
		const newEntry = await skynet.setEntry(privateKey, appId,
			{datakey: appId, data: newLink, revision: 0}
		);
		return true;
	} else {
		const link = entry.entry.data;
		const newLink = await appendKey(key, link, appId);
		if (newLink == '') {
			return false;
		}
		const newEntry = await skynet.setEntry(privateKey, appId,
			{datakey: appId, data: newLink, revision: 0}
		);
		return true;
	}
}

// check if the key exists in the database
export async function keyExists(key, appId) {
	const seed = buffer.Buffer.from(crypto.HashDataKey(appId)).toString('hex');
	const {publicKey, privateKey} = crypto.keyPairFromSeed(seed);
	const entry = await skynet.getEntry(publicKey, appId);
	if (entry) {
		const database = await skynet.downloadText(entry.entry.data);
		if (!database) {
			throw new Error('Could not locate database');
		}
		let text = database.text.slice(database.text.indexOf('{') + 1, database.text.indexOf('}'));
		const aesKey = crypto.HashAll(crypto.encodeString(appId), crypto.encodeString(key));
		const aesEcb = new aes.ModeOfOperation.ecb(aesKey);
		if (text.length > 0) {
			const decrypted = aes.utils.utf8.fromBytes(aesEcb.decrypt(base64.Base64.toUint8Array(text)));
			if (decrypted.indexOf(key) >= 0) {
				return true;
			}
		}
	}
	return false;
}

// create a unique appId
// this function should be used only once for each app
export function createAppId(appId) {
	if (appId.length >= 32) {
		return appId;
	}
	const asciiChars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.split('');
	let result = appId + '-';
	for (let i = result.length; i < 32; i++) {
		result = result + asciiChars[Math.floor(Math.random() * asciiChars.length)];
	}
	return result;
}