How dare you claim I am not deadly serious about the NSA putting a back door in a database that is intended to be secure for the internet. How. Dare. You!
I've seen a possible back door or two in this or that, but nothing like "every crypto system ever".
If you have evidence of a back door in AES, SHA-2, or anything NIST has standardized (other than Dual_EC_DRBG or openly weakened stuff like export SSL) lots of people would like to hear about it.
They also reduced the key length from 64 to 56 bits. I found this suspicious and didn't accept the explanation that those 8 bits were needed for "parity". Yet, respected cryptographers say this actually brings the key size more in line with the effective strength. So those additional 8 bits in the key were not contributing to the security and it improves the "truth in labeling".
Why would they build weaknesses into standard blocks, the biggest consumer of which is the US government itself?
When the NSA had at times insisted on an upper limit for a protocol's security (e.g., export crypto), they usually would require a simple upper limit on the number of secret bits in the key. When they've submitted fixes they tend to be elegant and minimal (e.g. SHA-0 to SHA-1).
I don't know much about security, but I am vaguely aware that there were some efforts by various governments to control, regulate, weaponize and even outlaw crypto, but I don't know where these effort have left us. Are there any crypto systems with acknowledged backdoors? Are there any which are not only widely considered to be secure, but are known to have actually prevented three-letter agencies from getting their way?