undisclosed
They are secrets that, by his own admission, the chairman would rather were left unrevealed.
There are bound to have been other shocking incidences of waste as yet unrevealed.
A wholesaler sells goods to retailers at a price which includes an unrevealed margin.
There had to be unrevealed deals to secure testimony, even though they repeatedly denied it.

SMART Vocabulary: related words and phrases

Secrecy and privacy
anonymity
anonymization
anonymize
anonymous
anonymously
cryptography
data protection
dead men tell no talesidiom
dissimulate
dissimulation
official secret
on the quietidiom
privacy
privacy settings
private
under the tableidiom
under wrapsidiom
undisclosed
unsourced
unstated