The core of this root is to conceal. Litzpon (לִצְפֹּן) is to hide, to store away. From that one idea, three surprising branches grow. First, the hidden message: a tzofen (cipher) and hatzpana (encryption) are meaning deliberately concealed. Second, and stranger, the north: tzafon (צָפוֹן) is the hidden, shaded direction, the dark quarter the sun never reaches, so a compass that finds it is a matzpen (מַצְפֵּן). Third, the deepest hidden thing of all: your matzpun (מַצְפּוּן), conscience, what is stored away inside you. Hide, north, conscience: one root, three depths. Every word here is verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
A clean three-way set: pa'al is to hide, nif'al is its passive (to be hidden), and hif'il carries the modern technical sense (to encrypt) plus, remarkably, to orient northward, since north is the hidden direction. The pi'el, pu'al, huf'al and hitpa'el are not lexicalized for this root.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.