DIP-212 Activity Content Additional Hash

[wilwade]

Abstract

Adding support to Activity Content Hash for:

• Blake2b
• SHA-256

Motivation

Additional hashes allow for an easier integration on creation and support for a variety of platforms and languages, although it does increase the potential burden for consumers of the data who must support multiple hashing algorithms to be able to verify content using any hash.

Specification Pull Request

Current change pull request: #245

Rationale

We have always intended to support multiple hashes. The rational for each is different:

Chosen

• Blake2b: With the support for DSNP on Frequency, Blake2b is already used in other places
• SHA-256: A hash standard in many applications

Rejected for Now

• Blake3: Is already starting to get some use and is amazingly fast, however it is very new
• sha3-256: keccak-256, which is a pre-release of sha3-256 that is used by Ethereum, support for the official final version may be worthwhile.

Chosen Path: Multihash

Support for multihash instead of the prior v1.0 version. This brings everything into alignment with #210

Backwards Compatibility

This will break validation for all implementations. It is suggested that those who can, take advantage of using multiple algorithms for some time before using only one or more hashing algorithms in the new version.

Reference Implementation and/or Tests

None

Security Considerations

This change will allow for increased security as it decreases the likelihood that all hashing algorithms in use will be broken at the same time.

Dependencies

• None.

References

• RFC 6234
• RFC 7693

Copyright

Copyright and related rights waived via CC0.

[wesbiggs]

I have created PR #245 that includes changes to the Activity Content spec to use multihashes.