multidid

A very compact representation of DIDs and DID URLs

Multidid is a representation strategy for DIDs and DID URLs that is very compact and extensible. It allows any DID method to be represented as a string of bytes.

Format

<multidid-code><method-code><method-bytes><url-length><url-bytes>

Where:

• multidid-code - the value 0x0d1d encoded as a multiformats varint
• method-code - a varint encoded multicode for the DID Method identifier
• method-bytes - data representing the method-id
• url-length - a varint describing the length of the url-bytes parameter
• url-bytes - a UTF-8 encoded string representing the DID URL parameters

Method multicodes

By default, DIDs from any DID method can be represented by using the 0x55 code (representing "raw" data) as the method-code, which allows the url-bytes to contain an entire DID URL, including arbitrary method identifier, paths, query parameters, etc. To take advantage of a more optimized representation, specific DID methods can claim entries in the method-code table by submitting a specification to the methods folder in this repository which claims a prefix in the multicodec table, and adding it to the method table below.

Method specific identifier length

The main constraint on all specific method-multicodecs is that for a given code, the length of the method specific identifier, the method-bytes, MUST be known. Otherwise it would be impossible to know when to start parsing the url-bytes.

Registered method multicodes

Code	Method
0x55	did:*
0xe7, 0xeb, 0xec, 0xed, 0x1200, 0x1201, 0x1202, 0x1205	did:key
0xca	did:pkh

Editors

• Joel Thorstensson, 3Box Labs
• Juan Caballero, CASA

Authors

• Irakli Gozalishvili, DAG House
• Joel Thorstensson, 3Box Labs

References