Live CVR transmission
Encryption will never work as designed in all jurisdictions. Some CAA/airlines will not subscribe unless they can hold the keys. Just like some don't allow CVR erase buttons, as were prescribed in the original international agreements.
Either that or hackers will be employed to decrypt for surreptitious spying!
If implemented, I can see the newspaper transcriptions of CVR broadcasts.
Some form of DFDR upload may have some short term benefit. But will it outweigh the cost? The accident report will still take just as long to compile. All will happen is that a lot of this bad taste 'armchair investigation' will be avoided.
There is only one event in history where the black boxes haven't been found, so what is the real 'cost' advantage?