You may use it for personal communications, but others can hear/see/decode what you're saying/sending. I hear people on 2m repeaters talk with their spouses about going to the grocery store all the time, but the point is, everyone else can hear it. If you need your communications encrypted, you need to use a different band or service.
FCC Part 97.113, "Prohibited transmissions":
> Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification.
(I believe the only "otherwise provided herein" obscured communications are control commands sent to satellites, to ensure they cannot be improperly controlled.)
I believe pretty much any outside of the amateur bands that you're able to get appropriately licensed for. I know the commercial "business band" can be encrypted, ISM low-power bands can be encrypted (i.e. the same band WiFi and Bluetooth uses at 2.4GHz), and obviously cell phone transmissions are.
FCC Part 97.113, "Prohibited transmissions":
> Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification.
(I believe the only "otherwise provided herein" obscured communications are control commands sent to satellites, to ensure they cannot be improperly controlled.)
http://www.arrl.org/files/file/Regulatory/March%208,%202018....