A designation or marking which identifies classified operational keying material, and which indicates that this material requires special consideration with respect to access, storage, and handling
[The] marking or designator identifying COMSEC keying material used to secure or authenticate telecommunications carrying classified or sensitive U S Government or U S Government-derived information Note: When written in all upper case letters, CRYPTO has the meaning stated above When written in lower case as a prefix, crypto and crypt are abbreviations for cryptographic [NIS]