de ‧ crypt /diːˈkrɪpt/ BrE AmE verb [transitive]
to change a message or information on a computer back into a form that can be read, when someone has sent it to you in a type of computer ↑ code ⇨ encrypt :
Only certain employees will be able to decrypt sensitive documents.
—decryption /diːˈkrɪpʃ ə n/ noun [uncountable]