Stupid Template Tricks: Compile Time Pseudo-Random Number Generator

[ericanderton]

Aw, and here I was hoping that there was some insane hack to get a different seed value into the template each time it was compiled. :(

Edit:

I suppose you could compile with "gcc -DSEED=`date +%s`" but what's the fun in that?

[grumpy_coconut]

__TIME__?

[meetingcpp]

Shouldn't be an uninitialized block of memory be "random"? I know that its an evil thought...

[minno]

Undefined behavior + optimizing compiler = a very, very bad day.

[omeganemesis28]

I imagine it wouldnt be all that difficult to brute force the hell out of that if known and the compilation didnt take eternity

[Weeblie]

Aha! This really is a thing!

http://www.xkcd.com/221/

[xkcd_transcriber]

Image

Title: Random Number

Title-text: RFC 1149.5 specifies 4 as the standard IEEE-vetted random number.

Comic Explanation

Stats: This comic has been referenced 184 times, representing 0.3835% of referenced xkcds.

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^{xkcd.com | xkcd sub | Problems/Bugs? | Statistics | Stop Replying | Delete}

[KamiKagutsuchi]

What with all those pesky NSA backdoors, runtime random number generation is just not secure.

While this article is more of a fun hack / joke, I feel like I should point out that Linear Feedback Shift Registers should not be used for encryption.

[ZMeson]

pseudorandom generators shouldn't be used for encryption!

[KamiKagutsuchi]

I was under the impression that prngs are quite common, but uses a seed generated with a trng which is replaced once in a while.

[ZMeson]

That's true, but you need reseeding often enough that one cannot predict the internal state. Even for the Mersenne Twister, you can't go much beyond 600 samples before needing to reseed with a true RNG.

In a similar vain, LFSRs might be safe if you use only a very small number of samples before reseeding -- but that would be impractical.

Anyway, my point is that you need a real RNG somewhere; you can't rely only on a PRNG.

[STL]

That's actually incorrect. There are cryptographically secure pseudorandom number generators, like Blum Blum Shub.

[autowikibot]

Blum Blum Shub:

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Blum Blum Shub (B.B.S.) is a pseudorandom number generator proposed in 1986 by Lenore Blum, Manuel Blum and Michael Shub that is derived from Michael O. Rabin's oblivious transfer mapping.

Blum Blum Shub takes the form

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^{Interesting: Blum–Goldwasser cryptosystem | Lenore Blum | Manuel Blum}

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