Re: Is ActivityStreams Collection under-specified?

> it says nothing about the interface for performing even basic CRUD
operations on those Collections. (e.g. CRUD = Create, Read, Update, Delete)

i'm not sure why you would apply CRUD to Collections. we have Add and
Remove.

> If I want to sign, or encrypt a Collection, or some or all of its
elements, I get no guidance from any of the existing Activity*
specifications. If I look around hard enough, I might stumble across
the Verifiable
Credential Data Integrity <https://w3c.github.io/vc-data-integrity/> and
find in it some guidance on signing chunks of JSON-LD, but I'm not really
sure if anyone else would be able to understand such signed JSON-LD.

yes, ActivityStreams and ActivityPub do not mandate any specific
authentication or verification or proof mechanism. if they had, they would
very quickly be outdated. i'm sure more work is ongoing with VCDI regarding
this general issue of verifiability and data integrity proofs, some
discussion of which can be found with FEP-8b32:
https://socialhub.activitypub.rocks/t/fep-8b32-object-integrity-proofs/2725
-- the problem of course is deciding on a cryptosuite. cryptosuite churn is
the biggest problem in general, as any proof you generate today will
probably soon be useless on account of no one knowing how to verify it in a
few years. see RsaSignature2017 as used in mastodon's implementation of the
old Linked Data Signatures draft, which is not even defined anymore since
it was formalized as RsaSignature2018, and even *that* is still a draft.

> If items in my collection need to refer to each other

refer *how*, precisely? `tag` is intended as a general "inclusion by
reference" mechanism, but there also exists the more specific `inReplyTo`
for when your object is in some way a response to another object.

> how can I spend more time coding and less time digging through discussion
lists of standards groups?

i'm not sure there's a good answer to this question. if you want to
implement a standard then you'll probably end up looking at either the
standard itself, or at some implementation guide or tutorial.