If you think the government can decrypt current secure encryption methods (e.g. 256+ bit AES) in reasonable timeframes you don't know what you are talking about.
Advanced Encryption Standard - Wikipedia, the free encyclopedia
All the algorithms for generating these encryptions are publically disclosed. You can encrypt something in AES using the algorithm and a god damn fucking calculator. How can a backdoor be incorporated into that? Thousands of people use AES and do research into it. Any feasible back door in the 100% public algorithm would have been discovered.
Arguing that the government somehow can break them, or has a back door, is akin to saying that the government could e.g. solve differential equations in some special way no one knows about. It's not mathematically feasible.
As was also highlighted, even with quantum computers, it'd take years and years to brute force.
If I was the NSA I'd forget about bruteforcing encryption methods and focus on the stuff people commonly fuck up. E.g. using stupid keys, hacking into people's computers to get the keys in the first place, listening in on insecure networks, yada yada. There's much more "low hanging fruit" out there. The easiest way to decrypt this stuff is to deal with the weak link in the chain, which more often than not is the people exchanging the encrypted info unless they are diligent.