encrypt (v.)

word-forming element meaning "in; into," from French and Old French en-, from Latin in- "in, into" (from PIE root *en "in"). Typically assimilated before -p-, -b-, -m-, -l-, and -r-. Latin in- became en- in French, Spanish, Portuguese, but remained in- in Italian.

Also used with native and imported elements to form verbs from nouns and adjectives, with a sense "put in or on" (encircle), also "cause to be, make into" (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as ensure/insure, and most en- words in English had at one time or another a variant in in-, and vice versa.

before vowels crypt-, word-forming element meaning "secret" or "hidden, not evident or obvious," used in forming English words at least since 1760 (crypto-Calvinianism), from Latinized form of Greek kryptos "hidden, concealed, secret" (see crypt; the Greek combining form was krypho-).

In 19c. often of secret religious faith; from 1870s in scientific words; since c. 1945 typically of hidden political loyalties. Crypto-fascist is attested from 1937; crypto-communist from 1946. Hence, as an abstracted noun, crypto "person who conceals a political adherence" (1946).