"Crypto", as a short form for "Cryptocurrency", is a regular noun. A guy named "Crypto", well, that's called a proper noun. But in both cases "Crypto" is a noun, and in Latin, the ending of a noun gets changed according to how it's used in a sentence. In your motto, "crypto" needs to be either in the dative or ablative case (serious grammar terms), and since it ends in letter "o", that means it has to end in -oni for dative, or -one for ablative.
Example: Spartacus gives money to Cicero = Spartacus pecuniam ad Ciceronem dat
Example: Cicero gives money to Spartacus = Cicero pecuniam ad Spartacum dat
So the words change ending when they're used in different places in the sentence. In English and most other European languages today, we use word order mostly to understand the grammar, but in Latin, it was word endings.
Edit: I don't know what "cryptocurrency" would be in Latin, but there IS a word for it, because the Vatican still uses spoken Latin and keeps an up-to-date dictionary of terms. I might be able to find out.
Thanks for the good explanation !
My mother tongue is french, so that may explain my mistake about regular noun and proper noun.