[odopxdlr] Depopularizing cryptography

Assuming you are a three-letter agency whose surveillance efforts would be hampered by mass adoption of cryptography, how would you prevent it?

In particular, thwart the adoption of truly distributed cryptography, because centrally controlled cryptography can be subverted by compromising the central control.

Also in particular, thwart cryptography technologies whose mass adoption will be spurred by a critical mass of adopters: once enough people start using it, everyone else will want to also.

All this is speculation of psychological warfare on a mass scale, speculating malice when incompetence is probably enough.

Skype used to be one example of mass adoption of distributed peer-to-peer cryptography, something about its directory or possibly NAT traversal.  However, after it was purchased by Microsoft, that feature got centralized through Microsoft's servers.  Was the sale of Skype to Microsoft aided by a three-letter agency?

IPv6 would, I think, aid deployment of P2P cryptography by making NAT traversal unnecessary.  Is malice slowing its deployment?