> Well, I feel that encrypting traffic inside the data center is not a bad idea (and we do it at WePay where I serve as CSO).
Do you have your own data center building? And if you don't have your own data center buildings, how are you guarding against physical attacks? Because just saying "encryption" doesn't actually mean anything. Encryption isn't free, and at Google scale that can add up. Useless encryption is just wasted power
> For example, I don't want our system administrators to have an easy way to look at the traffic: yes, it is still possible to do but it is harder and requires some very unusual actions that will trigger alerts everywhere.
That can be accomplished in many ways that don't involve encryption. And your servers are all capable of decrypting the data at some point, so you still have to trust your sys admins and/or have alternative systems in place as they still have access to the unencrypted data.
> A good security will have in-depth defense and built-in monitoring/audit measure that would at the very least allow you to determine what have happened post-factum.
How, exactly, do you detect cable splicing? Much less audit said splicing? You seem to be asking for a hell of a lot more than "good security"