bc-ur-ts encodes binary data as URIs and animated QR sequences using the Uniform Resources specification, including fountain-coded multi-part transmission.
Uniform Resources (URs) are URI-encoded CBOR structures developed by Blockchain Commons. This package is intended primarily for use in higher-level Blockchain Commons projects like Gordian Envelope.
It is a requirement of the UR specification that the CBOR encoded as URs conform to Gordian dCBOR, which is a deterministic profile of CBOR specified in this IETF Internet Draft.
@blockchaincommons/uniform-resources is published to npm. Install it with your package manager of choice:
npm install @blockchaincommons/uniform-resources
# or
pnpm add @blockchaincommons/uniform-resources
# or
yarn add @blockchaincommons/uniform-resources
# or
bun add @blockchaincommons/uniform-resourcesimport { UR, URError, MultipartEncoder, MultipartDecoder } from "@blockchaincommons/uniform-resources";
import { encodeBytewords } from "@blockchaincommons/uniform-resources/bytewords";
import { cbor } from "@blockchaincommons/dcbor";
// Single-part.
const ur = UR.from("test", cbor([1, 2, 3]));
ur.toString(); // "ur:test/lsadaoaxjygonesw"
ur.toQRString(); // "UR:TEST/LSADAOAXJYGONESW"
UR.parse("ur:test/lsadaoaxjygonesw").equals(ur); // true
// Multipart (animated QR): an infinite fountain of parts, decoded in any order.
const encoder = new MultipartEncoder(ur, 10);
const decoder = new MultipartDecoder();
for (const part of encoder) {
decoder.add(part);
if (decoder.done) break;
}
decoder.result?.equals(ur); // true
// A scanner that may see either kind lower-cases the payload (the multipart
// decoder is case-sensitive, as the reference's) and dispatches on the
// `n-m/` header, as a caller of the reference does: `MultipartDecoder`
// rejects a single-part UR.
const scanned = "UR:TEST/LSADAOAXJYGONESW".toLowerCase();
const isMultipart = (s: string) => /^ur:[^/]*\/\+?\d+-\+?\d+\//.test(s);
isMultipart(scanned); // false → UR.parse(scanned)
// Bytewords.
encodeBytewords(new Uint8Array([1, 2, 3, 4, 5]), "standard"); // "acid also apex aqua arch fuel bald nail work"
try {
UR.parse("ur:test/lsadaoaxjygonese");
} catch (e) {
if (URError.isURError(e)) console.log(e.code, e.message); // "Decoder", "UR decoder error (invalid checksum)"
}
// Failures are URErrors with the reference's codes and messages; an
// argument outside its domain is `InvalidParameter`. Branch with `is`, and
// read `details` by code.
try {
new MultipartEncoder(ur, 1.5);
} catch (e) {
if (URError.isURError(e) && e.is("InvalidParameter")) {
console.log(e.details.parameter, e.message); // "maxFragmentLength", "… must be an integer in [1, …] or a bigint in [1, …], got 1.5"
}
}
// The encoders are infinite by design: break out of `for … of` when done,
// or take a prefix with the iterator helpers (Node >= 22).
const three = encoder[Symbol.iterator]().take(3);Runnable examples live in the examples/ directory.
bc-ur-ts is currently under active development and in beta testing. It should not be used for production tasks until it has had further testing and auditing. See Blockchain Commons' Development Phases.
- 1.0.0-beta.3 (September 14, 2026) - Decoding follows the reference's
urcrate in full: fountain completion, no CRC-32 check on reassembly,seqNum0, minicbor part CBOR and messages, a case-sensitiveMultipartDecoderthat validates after completion,UR.parsein the reference order withDecoderfor bytewords failures, the empty UR type,decodeURWithon the first tag only with a dcborCborErrorfor a wrong type, ASCII-onlycanonicalizeByteword, frozen tables, argument validation on every export, and abigintmaxFragmentLength. - 1.0.0-beta.2 (September 12, 2026) - Decoding follows the reference:
bytewordsdecoding is case-sensitive,MultipartDecoderrejects single-part URs and reads the fountain fields from the CBOR (the header is parsed as twou16s, a leading+allowed), and a zeromaxFragmentLengthreports the reference's decoder error. - 1.0.0-beta.1 (September 9, 2026) - Initial beta implementation.
- Continued testing and auditing on the path from beta to a stable 1.0.0 release.
@blockchaincommons/uniform-resources depends on @blockchaincommons/crypto, @blockchaincommons/dcbor at runtime.
To build and work on this library, you'll need the following tools:
- Node.js >= 22.12 - JavaScript runtime.
- Bun - used to install dependencies and run the TypeScript maintenance scripts.
- TypeScript >= 5.7 - language and type checker.
This bc-ur-ts project is either derived from or was inspired by:
- BlockchainCommons/bc-ur-rust - The reference Rust implementation, by Wolf McNally.
- paritytech/bcts - A TypeScript port of many Blockchain Commons' specs, by Parity Technologies.
bc-ur-ts is a project of Blockchain Commons. 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 bc-ur-ts and other projects, please consider becoming a Patron of Blockchain Commons through ongoing monthly patronage as a GitHub Sponsor. You can also support Blockchain Commons with bitcoins at our BTCPay Server.
We encourage public contributions through issues and pull requests! Please review CONTRIBUTING.md for details on our development process. All contributions to this repository require a GPG signed Contributor License Agreement.
The best place to talk about Blockchain Commons and its projects is in our GitHub Discussions areas.
Gordian Developer Community. 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. This is where you talk about Gordian specifications such as Gordian Envelope, bc-shamir, Sharded Secret Key Reconstruction, and bc-ur as well as the larger Gordian Architecture, its Principles of independence, privacy, resilience, and openness, and its macro-architectural ideas such as functional partition (including airgapping, the original name of this community).
Gordian User Community. For users of the Gordian reference apps, including Gordian Coordinator, Gordian Seed Tool, Gordian Server, Gordian Wallet, and SpotBit as well as our whole series of CLI apps. This is a place to talk about bug reports and feature requests as well as to explore how our reference apps embody the Gordian Principles.
Blockchain Commons Discussions. For developers, interns, and patrons of Blockchain Commons, please use the discussions area of the Community repo to talk about general Blockchain Commons issues, the intern program, or topics other than those covered by the Gordian Developer Community or the Gordian User Community.
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 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.
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 documentation.
| Name | Role | Github | GPG Fingerprint | |
|---|---|---|---|---|
| Christopher Allen | Principal Architect | @ChristopherA | <ChristopherA@LifeWithAlacrity.com> | FDFE 14A5 4ECB 30FC 5D22 74EF F8D3 6C91 3574 05ED |
| Wolf McNally | Lead Researcher/Engineer | @wolfmcnally | <Wolf@WolfMcNally.com> | 9436 52EE 3844 1760 C3DC 3536 4B6C 2FCF 8947 80AE |
| Leonardo Custodio | Software Engineer | @leonardocustodio | <leonardo@snowpine.io> | 59DA D997 67EF 3BAB 2B90 D057 5384 DEF3 B582 450D |
Blockchain Commons Uniform Resources (UR) for TypeScript was produced as a collaboration between Blockchain Commons and one of our patrons, Parity Technologies: Parity wrote the wrappers based on Blockchain Commons' specifications and reference libraries. Blockchain Commons is dedicated to not just creating open infrastructure on our own, but also coordinating the work of other companies in benefiting the Commons. Thanks to Parity for working directly with us in this manner.
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.
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.