It is contained in virtually every fertilizer mixture, with few exceptions, because it is so vital to the healthy growth of plants and the formation of flowers and fruits. The addition of potassium nitrate to a fertilizer mix has the identical effect on plant growth as other forms of potassium. To the plants, potassium is potassium, whatever humans call it or classify it as. Because of its high cost, potassium nitrate is not widely used in fertilizer mixes, according to the University of Minnesota Extension.
SCEP is a specialized protocol which has a smaller scope; it concentrates on enrollment and CRL obtention, and is definitely client/server (all messages are requests sent to the CA, and responses from the CA, while CMP allows for CA-driven exchanges).
ISTEP is a pass/fail test the state uses to measure student academic achievement. While failing the exam doesn't necessarily carry immediate consequences for a student, passing the newly instated 10th-grade test is now required for graduation.