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Comment by tptacek | Hacker News Reader

That comment isn't intended to be "chilling"; it's intended to be the opposite.

This is a terrible cryptographic backdoor. If you're going to backdoor cryptography, you do it cryptographically, so that only you and your partners can decrypt it (this is called a "NOBUS" backdoor, for "nobody but us"). The only reason nobody found the Infineon bug already is that nobody seriously looked for it.

The most plausible explanation for the Infineon bug is also the most widespread: there's prime number generation advice for quickly generating primes on low-power devices like smartcards, and that advice was badly flawed.

(This isn't the first time primegen bugs have created factorable public keys in the wild; Henninger has a similar attack relating to p = randomprime(start=0), q = randomprime(start=p)).

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Don your shiny crinkly hats, but after https://en.m.wikipedia.org/wiki/Dual_EC_DRBG I started believing that NSA involvement is not subtle in their exploits.

They only need to fool laymen, and backdoored primes are an easy way to do so. The number of true cryptography experts beyond their walls is a dozen in the world at best. Case in point https://en.m.wikipedia.org/wiki/Daniel_J._Bernstein . And BTW he's been sued by the US government for ???. Thank God the EFF has decent funding.

"The number of true cryptography experts beyond [the walls of the NSA] is a dozen in the world at best"?

This kind of logic is super common on HN threads and it's incoherent. If the expertise and capabilities of the NSA with respect to basic cryptographic mathematics is so unknowable that thousands of published academic cryptographers are wasting their time, then what makes you think a random amateur Math Overflow post has somehow stumbled on a deep secret of NSA RSA subterfuge?

For whatever it's worth to you, Dan Bernstein was not sued by the US Government. Dan Bernstein sued the US Government, over export restrictions on cryptography in the 1990s; his suit was mooted by the relaxation of those restrictions.

NSA made seemingly bening improvements to crypto standards that the academic community only discovered as valuable over a decade later.

They’re the largest single employer of mathmaticians in the world.

> NSA made seemingly bening improvements to crypto standards that the academic community only discovered as valuable over a decade later.

At the same time, they negotiated DES's key length down. It was 64 bits originally, the NSA wanted only 48 bits, IBM and the NSA compromised on 56 bits.

Note that the Dual EC DRBG backdoor you point to was in fact a NOBUS backdoor.

Do you honestly believe that China and Russia don't take cryptography seriously, and between them only employ a tiny handful of experts...?

The opposite. Government entities suck up all the world's crypto experts leaving very few working in the publics interest.

You mean except for every professor, postdoc, and grad student working in every crypto research group at every large CS department in the world?

If you could introduce a bias in implementations to generate primes of the form more often than random then it could be useful, right?

I'm not wearing my tin foil hat so I realize that in order to do that in the first place you'd probably already have enough influence to do much more than this. But just for the sake of a hypothetical...

There are backdoors you can introduce from that position that don't involve an n * 2^-700 probability of the pattern occurring non-maliciously.

Do tell...

I've looked through the source of several common RSA keygen implementations and noticed that there usually aren't many sanity checks afterwards.

But I've never really thought about what can go wrong there (by random chance or by exploit).

/me puts on tin foil hat ... what could the lizard people plant in there?

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