A cryptoperiod is the time span during which a specific cryptographic key is authorized for use. Common government guidelines range from 1 to 3 years for...

A single sheet is valid for a limited time (e.g. 6 hours), called a cryptoperiod. A DRYAD cipher sheet contains 25 lines or rows of scrambled letters...

relations to quantum physics U.S. code for a cryptographic key change; see cryptoperiod ⟨hj⟩, a two-letter combination used in some languages hj-reduction in...

lists that described the rotor arrangements, to be changed each day (the cryptoperiod) at midnight, GMT. The highest level traffic was sent using one-time...

KYK-13 fill devices and a special adaptor box and cable. The standard cryptoperiod was 7 days, i.e. keys had to be changed weekly. FASCINATOR was adopted...

Expired key - Key that was issued for a use in a limited time frame (cryptoperiod in NSA parlance) which has passed and, hence, the key is no longer valid...

desirability of fielding cryptographic equipment that was not classified. NSA cryptoperiod doctrine called for keys to be changed every 24 hours. Initially, these...

broadcast messages. As its name implies, the day key is valid (has a cryptoperiod in NSA parlance) for 24 hours and was changed at 00:01 hours. For the...