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The Raspberry Pi’s Hardware Random Number Generator

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Re: The Raspberry Pi’s Hardware Random Number Generator

#51

Earlier quoted context omitted.

If you are connected to the internet, why not get your randomness from http://www.random.org/ ?

This thread is a joke, right?

What's a joke?

There is nothing ridiculous about using network timing as random, that's how /dev/random already works.

There is nothing ridiculous about using random.org, though that should be https.

Re: The Raspberry Pi’s Hardware Random Number Generator

#52
post #48
post #37

Earlier quoted context omitted.

If you don't trust a chip vendor's remote patching, there's nothing you can trust on the chip cryptographically at all.

Are there any possible realistic solutions to the trusted hardware issue?

Design and build it yourself?

Re: The Raspberry Pi’s Hardware Random Number Generator

#53
post #8

Does anyone have a link for a spec for the RNG? Specifically, where does it get its entropy from? Couldn't find it in the source link. Only mention I could find is a vague mention of "thermal noise" which could mean anything.

The SoC datasheet has this to say about the RNG http://pastehtml.com/view/crkxyohmp.rtxt Which is not particularly helpful.

How it works is basically undocumented although I hear the RPi engineers believe it uses some sort of thermal noise as the source for entropy.

Broadcom do have HWRNG patents though...

https://www.google.co.uk/patents/US6748495 https://www.google.co.uk/patents/US8229108

Re: The Raspberry Pi’s Hardware Random Number Generator

#55

Earlier quoted context omitted.

This thread is a joke, right?

What's a joke? There is nothing ridiculous about using network timing as random, that's how /dev/random already works. There is nothing ridiculous about using random.org, though that should be https.

> There is nothing ridiculous about using random.org, though that should be https.

Everything is wrong about this.

• You can not trust SSL to protect your source of entropy.

• You can not trust an external, unverified source of entropy.

Re: The Raspberry Pi’s Hardware Random Number Generator

#56

Earlier quoted context omitted.

Being naturally suspicious, I can't help wondering why the Broadcom chip on the Raspberry Pi doesn't have full technical specs publicly available. Seriously, why not?

Their customers are device makers, not small time developers or end users. They just don't want to disclose the information to people without various agreements (and hard sales leads) in place.

http://www.inquisitr.com/618772/raspberry-pi-tops-1-million-...

For this particular chip, you'd think they'd make an exception. But nooooooo.... Can't have those damned hackers actually knowing the register names, addresses and bit functions. That would be unthinkable.

Re: The Raspberry Pi’s Hardware Random Number Generator

#57
So OK, the Pi has a thermal RNG. Next question - does this: http://www.damninteresting.com/random-event-generators-predi... (and google for related articles) supposedly only happen for some types of hardware RNGs? Nuclear decay based RNGs? Or all types - thermal, semiconductor shot noise, wind-chimes or whatever?

Sounds like a candidate for large scale experiment.

Re: The Raspberry Pi’s Hardware Random Number Generator

#58
post #53
post #8

Does anyone have a link for a spec for the RNG? Specifically, where does it get its entropy from? Couldn't find it in the source link. Only mention I could find is a vague mention of "thermal noise" which could mean anything.

The SoC datasheet has this to say about the RNG http://pastehtml.com/view/crkxyohmp.rtxt Which is not particularly helpful. How it works is basically undocumented although I hear the RPi engineers believe it uses some sort of thermal noise as the source for entropy. Broadcom do have HWRNG patents though... https://www.google.co.uk/patents/US6748495 https://www.google.co.uk/patents/US8229108

Bah. Both those patents are just basically traditional linear feedback shift register systems, plus some fudging to try and make the results better.

Re: The Raspberry Pi’s Hardware Random Number Generator

#59

Earlier quoted context omitted.

If you are connected to the internet, why not get your randomness from http://www.random.org/ ?

This thread is a joke, right?

I was waiting for someone to offer offsets to Pi. (Pick a number, count that many digits of Pi, start using the rest of the digits as your RNG numbers.)

Re: The Raspberry Pi’s Hardware Random Number Generator

#60

The article is a bit vague about what exactly they're trying to say. What was unexpected? I read it three times before I decided they're comparing a lousy homegrown software RNG to the Pi's hardware RNG, which turns out to be good. Yes? Why would that be unexpected?

I wrote the article.

I'm guessing not everyone on HN is a huge fan of “Strictly Ballroom”, as the title is a key quote for dance movie otaku. It was also a weak joke about testing for random numbers; I'm imagining a little subroutine in a constant state of surprise when it encounters the next random number.

While I'm not sure if I implemented it correctly, RANDU isn't some ‘lousy homegrown software RNG’. It was the standard RNG for IBM mainframes in the late 1960s.

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