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NSA's Suite B Cryptography suggests some cryptographic algorithms for encryption, digital signatures, message digests and key agreements. The selected algorithms and their key size are suggested by the security level needed.

But is there any reason to think that the NSA suggests those algorithms because they know backdoors or something like that? Is it really secure to rely on those algorithms? Or should one assume that the NSA just suggests these algorithms in order to make people use algorithms with backdoors?

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It mainly depends on how the algorithm was selected. If it was selected by a public competition like for AES, then it is likely to be secure. If it was forced in by the NSA such as Dual-EC random number generator, then you may have some doubts.

Other questions you may want to ask yourself are:

  • Is this an "original" algorithm or was the problem that it relies on already known?
  • Is there a formal proof (often not possible), checked by independent persons or organizations?

In the end you will always have a grey area here. Some things like AES are probably secure, Dual-EC certainly is not. But for the (NIST/SECP) ECC parameters it's a lot harder to say.

Saying that Suite B is safe or not is a blanket statement that oversimplifies what is happening in the field of cryptography.

As it is highly visible, it will be highly scrutinized by the cryptographic community. But as Dual-EC proves nothing is to be fully trusted.

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Sorry, that may not be the answer you were hoping for, but you cannot simplify every question until you can just answer with "yes" or "no". –  owlstead Aug 16 at 13:34
    
Thans for the answer. So how does one say whether the ECC parameters are safe? Are there any independant analyzes of the Suite B components? –  MinecraftShamrock Aug 16 at 13:36
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There are efforts like safecurves.cr.yp.to , that try and solve this scientifically. Basically they are saying that the curves could have been better, and that the missing reasoning on how the input parameters have been chosen leaves room for doubt. No yes/no answer, as I've already indicated. Either somebody proves that no attacks are present, or somebody shows that there are (both are very hard - and maybe impossible - to accomplish). Before that no final yes/no answer can be composed. –  owlstead Aug 16 at 13:43
    
Thanks for the link. –  MinecraftShamrock Aug 16 at 14:21

There are good reasons to think an algorithm being in Suite B is evidence NSA thinks it's secure (they are used to protect classified materials). There are also reasons to think algorithms they recommend for others may not be (it's happened before).

So I don't think you can objectively say much about an algorithm either way just on the basis of whether it's included. You should instead look at the algorithm itself, including all published cryptanalysis, as well as who's designed it and how.

(The designers are almost always in a privileged position to backdoor an algorithm.)

Related:

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Good point. And thanks for the links :) –  MinecraftShamrock Aug 16 at 20:57

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