YanoSec / Code
Original fictional provenance: notes about where the strings came from.
These notes did not come from a real system.

Blob A: stored by the desk as Base64 of a label.
Blob B: stored by the desk as hex of that same label.
Blob C: copied from a slide title. Origin of the characters is unknown.
No item names a hash algorithm, a key, or a signature.
Decode only the item whose note names an operation. Leave blob C as ambiguous.