"MuPDF versions before 1.28.5 use an implementation of the drand48 family" yeah, ok, so they're basically not doing real encryption. The number of bits in the key space isn't the real story; the keys simply aren't cryptographically random.
btw, the idea that the system rng isnt good enough, or "runs out" or whatever, is no longer true on pretty much every modern, widely used os.
btw... im sure there's some legacy rng in windows or some shit that isnt good. read the docs but if it's the blessed system rng, you're probably fine!
although... i suppose if this is news to you, then you probably shouldn't be implementing whatever you are that really requires prng. ask a friend for help. im not trying to be a jerk, i just want to make sure you dont hurt yourself!
I think the claim is hyperbolic, since most people memory-unsafe PDF implementations, but PDF is a monster format, a metaformat that brings in virtually every conceivable display format, and their renderer implementations with them, often poorly-maintained, never-touched reference implementations from the before times. PDF is pretty scary.
16 comments:
"MuPDF versions before 1.28.5 use an implementation of the drand48 family" yeah, ok, so they're basically not doing real encryption. The number of bits in the key space isn't the real story; the keys simply aren't cryptographically random.
Rule #1 of rolling your own RNG: don’t.
Rule #2? Please don’t.
That's why we use the system RNG !
btw, the idea that the system rng isnt good enough, or "runs out" or whatever, is no longer true on pretty much every modern, widely used os.
btw... im sure there's some legacy rng in windows or some shit that isnt good. read the docs but if it's the blessed system rng, you're probably fine!
although... i suppose if this is news to you, then you probably shouldn't be implementing whatever you are that really requires prng. ask a friend for help. im not trying to be a jerk, i just want to make sure you dont hurt yourself!
Wonderful.
it's like the weak hardware wallet entropy bug
You'd have to be completely off your rocker to use a PDF tool written in C anyway.
very VERY few people judge tools like this by the language used to develop them.
How many people judge their tools based on the AES key entropy?
A lot actually.
You're confusing just assuming by default its enough for purpose rather than not caring at all.
just down vote it.
You can downvote anything not interesting.
If he have list some alternative or give example, it might be interesting.
What are the alternatives?
PDF.js, for example. It's what Firefox uses, and most websites with integrated on-page PDF viewing functionality.
Genuine question, since I'm not very knowledgeable about this: why is using C for a PDF tool such a bad idea?
I think the claim is hyperbolic, since most people memory-unsafe PDF implementations, but PDF is a monster format, a metaformat that brings in virtually every conceivable display format, and their renderer implementations with them, often poorly-maintained, never-touched reference implementations from the before times. PDF is pretty scary.
buffer overflow vulnerability in code dealing with user generated data and a complex file format.