seal of secrecy

Translations
печать секретности
The document was under a seal of secrecy.
Документ находился под печатью секретности.
Definitions
A seal of secrecy refers to a formal or official mark or symbol that signifies that certain information is to be kept confidential and not disclosed to unauthorized individuals.
Words
seal

noun
тюлень
secrecy

noun
секретность