# URKit

## An iOS framework for encoding and decoding URs (Uniform Resources)

### _by [Wolf McNally](https://www.github.com/wolfmcnally) and [Christopher Allen](https://www.github.com/ChristopherA)_

* <img src="https://github.com/BlockchainCommons/crypto-commons/blob/master/images/logos/crypto-commons-super-simple.png" width=16 valign="bottom">&nbsp;&nbsp; ***part of the [crypto commons](https://github.com/BlockchainCommons/crypto-commons/blob/master/README.md) technology family***

This framework is pure Swift 5 and is available via Swift Package Manager. It contains several major components:

* `UREncoder` and `URDecoder`, A codec for [UR](https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-005-ur.md)s that supports single-part and multi-part transmission using fountain codes.
* `FountainEncoder` and `FountainDecoder`: A general codec for binary strings based on [Luby Transform code](https://en.wikipedia.org/wiki/Luby_transform_code).
* `Bytewords`: A codec for [Bytewords](https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-012-bytewords.md).
* A codec for [CBOR](https://en.wikipedia.org/wiki/CBOR) based on [SwiftCBOR](https://github.com/myfreeweb/SwiftCBOR), from the Public Domain.

If you are using this framework at it's highest level, the main types of interest will be `UR`, `UREncoder`, and `URDecoder`.

The CBOR codec is provided because the message of a compliant UR must be encoded in CBOR, and multi-part URs embed fragment data in a CBOR structure containing metadata needed by the decoder. For your own UR structures, you can use a different CBOR codec as long as the message encoded is well-formed CBOR.

The other layers may be used independently if desired.

There is also an iOS app, [URDemo](https://github.com/BlockchainCommons/URDemo), that demonstrates URKit by sending and receiving long binary messages via animated QR codes containing multi-part URs.

## Status - Late Alpha

**URKit** is currently under active development and in the late alpha testing phase. It should not be used for production tasks until it has had further testing and auditing.

## Prerequisites

* Swift 5, iOS 13 or macOS 10.15, and Xcode 11.5

## Installation Instructions

* Build or include like any other Swift package. Unit tests are included.

## Origin, Authors, Copyright & Licenses

Unless otherwise noted (either in this [/README.md](./README.md) or in the file's header comments) the contents of this repository are Copyright © 2020 by Blockchain Commons, LLC, and are [licensed](./LICENSE) under the [spdx:BSD-2-Clause Plus Patent License](https://spdx.org/licenses/BSD-2-Clause-Patent.html).

In most cases, the authors, copyright, and license for each file reside in header comments in the source code. When it does not, we have attempted to attribute it accurately in the table below.

This table below also establishes provenance (repository of origin, permalink, and commit id) for files included from repositories that are outside of this repo. Contributors to these files are listed in the commit history for each repository, first with changes found in the commit history of this repo, then in changes in the commit history of their repo of their origin.

| File      | From                                                         | Commit                                                       | Authors & Copyright (c)                                | License                                                     |
| --------- | ------------------------------------------------------------ | ------------------------------------------------------------ | ------------------------------------------------------ | ----------------------------------------------------------- |


### Derived from…

**URKit** project is either derived from or was inspired by:

- [UR specification](https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-005-ur.md) — The specification for Uniform Resources

### Used with…

These are other projects that work with or leverage `$projectname`:

- [URDemo](https://github.com/BlockchainCommons/URDemo) — Demonstrates URKit by sending and receiving long binary messages via animated QR codes containing multi-part URs.


## Financial Support

**URKit** is a project of [Blockchain Commons](https://www.blockchaincommons.com/). We are proudly a "not-for-profit" social benefit corporation committed to open source & open development. Our work is funded entirely by donations and collaborative partnerships with people like you. Every contribution will be spent on building open tools, technologies, and techniques that sustain and advance blockchain and internet security infrastructure and promote an open web.

To financially support further development of **URKit** and other projects, please consider becoming a Patron of Blockchain Commons through ongoing monthly patronage as a [GitHub Sponsor](https://github.com/sponsors/BlockchainCommons). You can also support Blockchain Commons with bitcoins at our [BTCPay Server](https://btcpay.blockchaincommons.com/).

## Contributing

We encourage public contributions through issues and pull requests! Please review [CONTRIBUTING.md](./CONTRIBUTING.md) for details on our development process. All contributions to this repository require a GPG signed [Contributor License Agreement](./CLA.md).

### Discussions

The best place to talk about Blockchain Commons and its projects is in our GitHub Discussions areas.

[**Gordian Developer Community**](https://github.com/BlockchainCommons/Gordian-Developer-Community/discussions). For standards and open-source developers who want to talk about interoperable wallet specifications, please use the Discussions area of the [Gordian Developer Community repo](https://github.com/BlockchainCommons/Gordian-Developer-Community/discussions). This is where you talk about Gordian specifications such as [Gordian Envelope](https://github.com/BlockchainCommons/Gordian/tree/master/Envelope#articles), [bc-shamir](https://github.com/BlockchainCommons/bc-shamir), [Sharded Secret Key Reconstruction](https://github.com/BlockchainCommons/bc-sskr), and [bc-ur](https://github.com/BlockchainCommons/bc-ur) as well as the larger [Gordian Architecture](https://github.com/BlockchainCommons/Gordian/blob/master/Docs/Overview-Architecture.md), its [Principles](https://github.com/BlockchainCommons/Gordian#gordian-principles) of independence, privacy, resilience, and openness, and its macro-architectural ideas such as functional partition (including airgapping, the original name of this community).

[**Blockchain Commons Discussions**](https://github.com/BlockchainCommons/Community/discussions). For developers, interns, and patrons of Blockchain Commons, please use the discussions area of the [Community repo](https://github.com/BlockchainCommons/Community) to talk about general Blockchain Commons issues, the intern program, or topics other than those covered by the [Gordian Developer Community](https://github.com/BlockchainCommons/Gordian-Developer-Community/discussions) or the 
[Gordian User Community](https://github.com/BlockchainCommons/Gordian/discussions).

### Other Questions & Problems

As an open-source, open-development community, Blockchain Commons does not have the resources to provide direct support of our projects. Please consider the discussions area as a locale where you might get answers to questions. Alternatively, please use this repository's [issues](./issues) feature. Unfortunately, we can not make any promises on response time.

If your company requires support to use our projects, please feel free to contact us directly about options. We may be able to offer you a contract for support from one of our contributors, or we might be able to point you to another entity who can offer the contractual support that you need.

### Credits

The following people directly contributed to this repository. You can add your name here by getting involved. The first step is learning how to contribute from our [CONTRIBUTING.md](./CONTRIBUTING.md) documentation.

| Name              | Role                | Github                                            | Email                                 | GPG Fingerprint                                    |
| ----------------- | ------------------- | ------------------------------------------------- | ------------------------------------- | -------------------------------------------------- |
| Christopher Allen | Principal Architect | [@ChristopherA](https://github.com/ChristopherA) | \<ChristopherA@LifeWithAlacrity.com\> | FDFE 14A5 4ECB 30FC 5D22  74EF F8D3 6C91 3574 05ED |
| Wolf McNally      | Project Lead        | [@WolfMcNally](https://github.com/wolfmcnally)    | \<Wolf@WolfMcNally.com\>              | 9436 52EE 3844 1760 C3DC  3536 4B6C 2FCF 8947 80AE |

## Responsible Disclosure

We want to keep all of our software safe for everyone. If you have discovered a security vulnerability, we appreciate your help in disclosing it to us in a responsible manner. We are unfortunately not able to offer bug bounties at this time.

We do ask that you offer us good faith and use best efforts not to leak information or harm any user, their data, or our developer community. Please give us a reasonable amount of time to fix the issue before you publish it. Do not defraud our users or us in the process of discovery. We promise not to bring legal action against researchers who point out a problem provided they do their best to follow the these guidelines.

### Reporting a Vulnerability

Please report suspected security vulnerabilities in private via email to ChristopherA@BlockchainCommons.com (do not use this email for support). Please do NOT create publicly viewable issues for suspected security vulnerabilities.

The following keys may be used to communicate sensitive information to developers:

| Name              | Fingerprint                                        |
| ----------------- | -------------------------------------------------- |
| Christopher Allen | FDFE 14A5 4ECB 30FC 5D22  74EF F8D3 6C91 3574 05ED |

You can import a key by running the following command with that individual’s fingerprint: `gpg --recv-keys "<fingerprint>"` Ensure that you put quotes around fingerprints that contain spaces.