Three levels of Tempest standard NATO SDIP-27
Three different tempest standards can be defined. These are level A, B and C.
The tempest standard Level A is the strictest NATO-standard and is sometimes therefore referred to as ”Full”. This standard is thus for devices that are operated within the NATO Zone 0.
The tempest standard Level B is the next strictest NATO-standard, sometimes referred to as ”Immediate”. This tempest standard is therefore for devices that are operated within the NATO Zone 1.
The tempest standard level C is sometimes referred to as ”Tactical”. This standard is applied to environments and devices within the NATO Zone 2.
Tempest levels complete standard list
Standard Full Intermediate Tactical
NATO Zones Zone 0 Zone 1 Zone 0
NATO SDIP-27 Level A Level B Level C
NATO AMSG AMSG 720B AMSG 788A AMSG 784
USA NSTISSAM Level I Level II Level III