If HJKP is coded as SQPK, then FUON will be coded as:

Logic: Each letter is replaced by its reverse alphabetical counterpart (A↔Z, B↔Y...), where the sum of their positional values is 27.

• H (8) ↔ S (19)

• J (10) ↔ Q (17)

• K (11) ↔ P (16)

• P (16) ↔ K (11)

Applying this to FUON:

• F (6) ↔ U (21)

• U (21) ↔ F (6)

• O (15) ↔ L (12)

• N (14) ↔ M (13)

Thus, FUON is coded as UFLM.