Integrity protected container, analogue to ASN.1-based CMS DigestedData.
=> CMS

Stored in a file, it should begin with "cm/hashed" [encoding/MAGIC].
[schemas/hashed.tcl]
"/a" tells what algorithms will be used to hash the data.
"/t" tells the type of the data inside.
"/hash" contains the hash values for all corresponding "/a" algorithms.