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title: dCBOR Notes & Tweets

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# dCBOR Notes & Tweets

## Tweetstorm

(sent https://twitter.com/ChristopherA/status/1626305878520639488)

dCBOR (deterministic CBOR) is now available for Rust & Swift in a new codec library from @Blockchaincomns. Here's our announcement with all the links. [1/8] https://github.com/orgs/BlockchainCommons/discussions/184

Developers already utilizing CBOR should take a look, as this is a supported library with a focus on cryptographic use, that's also one of the few to concentrate on the deterministic flavor of CBOR. [2/8] 

Developers unfamiliar with CBOR may want to read our "Why CBOR?" article, which talks about its advantages such as conciseness, full extensibility, self description, and ease of use in constrained and streaming environment. [3/8] https://www.blockchaincommons.com/introduction/Why-CBOR/

We focused not just on CBOR, but the deterministic variant because it was crucial for our needs to produce repeatable hashes. We suspect other developers will have other use cases where determinism is important. [4/8]

We'd love to get comments on the libraries. Do they work for you? Are they intuitive? Did you run into any problems? What do you think of the API? How about the Rust idioms (if using Rust)? Are there code security tools that you'd like to see added? [5/8] https://github.com/orgs/BlockchainCommons/discussions/184

We'd also love to get your CBOR samples for use in demonstrations and examples, particularly identity and cryptography related samples such as mDLs and COSE data. [6/8]

We've been developing CBOR in part as a foundation for other projects such as Gordian Envelope, but we hope our work on CBOR itself is of use to everyone! [7/8] https://www.blockchaincommons.com/introduction/Envelope-Intro/

Please become a sponsor of Blockchain Commons to ensure that important interoperable and specification work of this sort continues! [8/8] https://github.com/sponsors/BlockchainCommons

## CCG Letter

(sent https://lists.w3.org/Archives/Public/public-credentials/2023Feb/0116.html )

Since I know that a lot of projects in the CCG WG already use CBOR, I wanted to announce Blockchain Commons' recent release of dCBOR libraries for Rust and Swift, allowing easy use of dCBOR with Android and with iOS:

* **dCBOR Codec for Rust**: https://github.com/BlockchainCommons/bc-dcbor-rust
* **dCBOR Codec for Swift**: https://github.com/BlockchainCommons/BCSwiftDCBOR

We've also produced a CLI using our Rust library, which can be used to test parsing and validation:

* **dCBOR CLI**: https://github.com/BlockchainCommons/dcbor-cli

We focused on the deterministic flavor of CBOR per [§4.2 of RFC-8949](https://www.rfc-editor.org/rfc/rfc8949.html#name-deterministically-encoded-c) because of our specific needs to produce deterministically repeatable hashes in the Merkle Tree underlying our [Gordian Envelope](https://www.blockchaincommons.com/introduction/Envelope-Intro/) data format. We suspect that there will be others who have similar needs and hope that the dCBOR libraries will prove useful!

I'd love to get any comments or thoughts you have on our dCBOR libraries, as well as any requirements that the libraries may not currently be meeting. I'd also love to get any CCG-related CBOR data that we can use in documents and examples, such as mDLs and COSE data.

I'm also happy to talk about [why we picked CBOR](https://www.blockchaincommons.com/introduction/Why-CBOR/) as a data format and why dCBOR is particularly advantageous, either here or in [our discussion forums at GitHub](https://github.com/orgs/BlockchainCommons/discussions/184). 

Thanks!

Christopher Allen
Blockchain Commons

## RWOT Signal

(Sent)

Blockchain Commons recently released a pair of dCBOR (deterministic CBOR) libraries and a dcbor-CLI for parsing and validation, which may all be of use to people here already using CBOR.

* **dCBOR Codec for Rust**: https://github.com/BlockchainCommons/bc-dcbor-rust
* **dCBOR Codec for Swift**: https://github.com/BlockchainCommons/BCSwiftDCBOR
* **dCBOR CLI**: https://github.com/BlockchainCommons/dcbor-cli

--

We focused on the deterministic flavor of CBOR per §4.2 of RFC-8949 (https://www.rfc-editor.org/rfc/rfc8949.html#name-deterministically-encoded-c) because of our specific needs to produce deterministically repeatable hashes, but we suspect that there will be others who have similar needs and hope that the dCBOR libraries will prove useful!

--

I'd love to get any comments or thoughts you have on our dCBOR libraries, as well as any requirements that the libraries may not currently be meeting. I'd also love to get any CCG-related CBOR data that we can use in documents and examples, such as mDLs and COSE data.

--

Thanks!
