Albedo

Albedo provides a safe and reliable way to use Stellar accounts without trusting anyone with a secret key.

It works like a bridge for other applications that allows them to ask permissions to sign a transaction or verify identity on user's behalf, so the same account can be used across the whole universe of Stellar applications. Sensitive data is encrypted and safely stored in the browser – no one has access to user's secret key.

From the developer's perspective, it takes only a few lines of code to turn any website into a production-ready Stellar wallet. Transactions building, signing, validation, errors handling – we have everything covered. There is no need to implement a keystore, build a dozen interfaces for transaction processing, and worry about security. In fact, things like payment request can be implemented without any coding at all, therefore allowing instant "stellarization" of any marketplace or even simple Wordpress site by simply copy-pasting code produced by the payment request generator.

At the same time, Albedo provides a set of low-level tools for working with complex multi-sig schemes, making it a perfect match for advanced Stellar-based applications and smart-contracts.

This project consists of two parts:

Frontend interface for albedo.link website and browser extension UI – a thin wrapper which extends the functionality of the main website.
Intent library – a lightweight browser wrapper for Albedo API that provides a promise-based interface for all supported intents.

For those who often use Stellar account we built browser extension – a thin wrapper on top of albedo.link website which has the same functionality as the main website, plus a few bonuses.

Features

Secure key management – secret keys never exposed to third-party services.
Secure transaction signing – browser sandbox guarantees isolated transactions signing environment.
Web apps Single Sign-On – login to third-party websites, just like with Google or Facebook OAuth.
Multi-account support – use multiple accounts and switch them when you need it.
Message signing tools – sign and verify arbitrary data with your private keys.
SEP-0007 compatible – automatically handles "web+stellar" links.
Works everywhere – the same account operates seamlessly on desktops, smartphones, and any other device that has modern browser installed.

How it works

The easiest way to start exploring Albedo is to play around with the demo playground.

Albedo can be integrated on any website in three simple steps:

Download and install Albedo intent NPM package:
```
npm i -S @albedo-link/intent
```

Import the intent interface:

import albedo from '@albedo-link/intent'

Invoke an intent as a reaction on button click or something similar:

document.getElementById('#btn').addEventListener('click', () => {
  albedo.pay({
    amount: '10',
    destination: 'GCKOQGMTULKR55EWNHAXXJLTL25J3LT6BHHLBMDAVFKX3E32PCYVBO7M',
    asset_code: 'TST',
    asset_issuer: 'GBX6YUG3KCUEOBZRPN7TXBLMNXDW35XJOKDYFYIISDKDW4Y63LBCW6EI',
    network: 'testnet'
  })
    .then(res => console.log(res)) // everything is ok, parse response here
    .catch(e => console.error(e))  // handle errors or user's rejection
})

Alternatively, you can import the UMD build in the browser directly from UNPKG:

<script src="https://unpkg.com/@albedo-link/intent/lib/albedo.intent.js"></script>

(albedo is available in a global execution context)

Available intents

The intent module supports the following actions ("intents"):

public_key - requests account public key
sign_message – requests arbitrary data signing
tx – requests transaction signing
pay – requests a payment
trust – requests new trustline creation
exchange – requests trading on Stellar DEX
implicit_flow – requests implicit session permission for one or more scopes

Check intent module docs for the detailed description, parameter definitions, and usage examples.

Authorization flows

The signer supports three authorization flows:

Interactive flow

A popup window with request details is shown each time an initiator website requests the action.

A user invokes some action on the third-party website (a wallet, DEX interface, inflation pool etc).
The website prepares the requested transaction and its XDR representation in base64 format. Alternatively, simple operations like pay or exchange can be used to request an action without building a tx.
The website initiates the intent (see available intents list) using albedo-intent module that provides an interface for all supported intents.
In turn, albedo-intent module opens new pop-up window pointing to albedo.link. Intent parameters are transmitted via postMessage API once the pop-up is open.
Albedo reads parameters and asks the user for a confirmation.
A user chooses an account from the list of stored accounts (or adds a new one) and confirms the action.
Albedo signs the transaction the same way any other wallet does it.
A signed transaction in the XDR-serialized form sent back to the initiator site.
The initiator website receives a signed transaction envelope and may choose either to submit it to the network or store somewhere in case if the tx needs more signatures or time bounds prevent it from submitting right away.

Intent confirmation dialog always contains extended request information, including intent description (like "Sign transaction"), initiator website ("origin: example.com"), risk level ("high", "medium", or "low"), and safety status ("safe" or "potentially unsafe").

Intent-specific details allow a user to review the request before confirmation. For instance, a dialog with tx intent displays full transaction information including all meaningful properties and the list of operations in a human-friendly format adapted for the ordinary users.

Implicit mode

Implicit mode simplifies recurrent tasks, like using DEX or sending multiple payments. It works similarly to OAuth. The application first requests permission to execute certain actions without showing the confirmation dialog window. If the a grants permission, a session token is created.

When application consequently asks for, say, signing a transaction, the intent module sends session token alongside with the request and the action is executed automatically, without showing a confirmation dialog. The session is valid for max 24h, or until the user closes the browser window. With interaction carried completely on the client-side, it is both secure and trustless.

This behavior allows implementing flow similarly to regular wallets. A user grants permission to the third-party application only once upon login and all other actions are executed transparently, without annoying repeated confirmations.

SEP-0007 flow

This callback-based flow supports SEP-0007 link format. When Albedo is set as a default web+stellar link handler (or when the browser extension installed), it redirects the browser to the signing interface instead of showing a pop-up authorization dialog.

A signed transaction can be either submitted to the network or returned to the provided callback URL via POST request.

Development

Please refer to

Frontend development section.
Extension development section.
Intent module development section.

Contributions

Contributions and suggestions are most welcome.

Please ensure that tests are passing before submitting the pull request.

npm test

Questions and feedback

Check the issue tracker for bug reports and feature requests.

thiagocapuano/albedo