Problem/Motivation
From #2983179-16: [META] Implement stricter access checking for the media library:
Right now, the media library depends on a state value object derived from URL query parameters. Users are not supposed to tamper with those parameters, but we have no mechanism in place to prevent that. So we need to implement a tamper-proof hash, similar to what Media does in its IframeUrlHelper class, to prevent people from messing with the query parameters in the first place.
Proposed resolution
Implement a tamper-proof hash, similar to what Media does in its IframeUrlHelper class, to prevent people from messing with the query parameters.
Remaining tasks
Write patch
Review
Commit
User interface changes
None
API changes
None
Data model changes
None