(Previously, previously, previously on An Algorithmic Lucidity.)
"The next thing we need is a secure way to communicate with our contacts on Bajor," says Maj. Kira during Act One of Deep Space Nine Season 6, Episode 3, "Sons and Daughters", planning the secret resistance to the Dominion's occupation of Deep Space Nine ... at a table in a public bar?! Who writes this stuff?
It's too much to retcon, but since we're getting a new series soonish, I'm going to hope for an episode where, as a plot point, some people (not necessarily the protagonists) use cryptography with their universal translators to evade would-be eavesdroppers: you'd stop speaking out loud and configure your universal translator to translate your subvocalizations into noise that can only be decrypted by one of the private keys in your friends' universal translators.
Maybe they have discovered that P=NP and there isn't any secure public key system or it turns out quantum computers effectively neuter computational (as opposed to OTP) encryption.
I'd take a failure to deploy encryption any day over any more inconsistent time travel episodes and I'll accept pretty much any crap if they stop lionizing their prejudices against genetic improvements.