Currency in vault, and what doubters think it's worth (6)
I believe the answer is:
crypto
'what doubters think it's worth' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'currency in vault' is the wordplay.
I cannot really see how this works, but
'vault' could be 'crypt' (I've seen this in another clue) and 'crypt' is found within the answer.
A single letter 'o' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for crypto that I've seen before include "Prefix denoting hidden or obscure" , "closet" .)