I don't want "only the 'good' people to have guns and encryption". I feel they are different:
Guns are used for two reasons: target practice (sport), and shooting to kill (hunt/attack/defend).
Encryption is used to keep communications secret.
We can have lengthy debates on the various uses of guns, but staying on topic, I find nothing wrong with people keeping communication secret. Sure, it'd be EASIER if the bad guys had to communication openly, but the "bad" isn't the communication, it's the bad things they DO.
I find nothing morally wrong with all people, including bad guys, being able to communicate in secret.
(The obvious retort is that there's nothing wrong with having guns, because it's the SHOOTING that might be bad, not the possession. Communication, however, exists for many reason, while guns exist for few, so I don't see the comparison as terribly valuable).