296 reputation
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location New York, NY
age 46
visits member for 8 months
seen 2 days ago

Jul
2
awarded  Curious
Jun
29
comment Entropy of Androids motion-sensor data
"... If l is less than 81% of the sensors Peek value the set of values is ignored..." - I think this is less than ideal. When you are trying to get a PRNG in good working order or keep a PRNG in good working order, use whatever you have. Don't throw less-than-perfect ones away. Peter Gutmann said similar: "...mix every entropy source you can get your hands on into your PRNG, including less-than-perfect ones...". From Heml.is - "The Beautiful & Secure Messenger".
Jun
29
comment Entropy of Androids motion-sensor data
On both Android and iOS, I perform similar. I use the sensors to gather a seed; and I don't sample the generator for prolonged periods of time. I grab two or three samples on app startup (or during a reseed), and then feed them to the crypto library's random number generator. You get an {x,y,z}-float triplet from the sensors. Just send them into the PRNG without preprocessing like ((int) x) ^ ((((int) y) ^ ((int) z)) << 16). What's the point of preprocessing and throwing bits away? Let the PRNG handle it. That's what it was designed to do.
Jun
18
revised Trial divisions before Miller-Rabin checks?
Added info on tainting answers.
Jun
18
comment Trial divisions before Miller-Rabin checks?
Thanks @Thomas. I appreciate the help. I would like to accept both answers, but I cannot.
Jun
18
accepted Trial divisions before Miller-Rabin checks?
Jun
18
comment Trial divisions before Miller-Rabin checks?
@fgieu - Forgive my ignorance.... Isn't this log base 2: $t=\lceil{1\over2}\cdot\lg n\rceil$? When I programmed it, I believe I calculated it as ceil( (log(k)/log(2))/2 ). I'm fairly certain k was bits, and not a random k-bit number. Unfortunately, I overwrote the test program already.
Jun
18
revised Trial divisions before Miller-Rabin checks?
deleted 5 characters in body
Jun
18
revised Trial divisions before Miller-Rabin checks?
Added edit about OpenSSL and Crypto++.
Jun
15
revised Trial divisions before Miller-Rabin checks?
Algorithm 4.4 -> Algorithm 4.44
Jun
15
revised Trial divisions before Miller-Rabin checks?
Added that 17863 is the 2048-th prime.
Jun
15
asked Trial divisions before Miller-Rabin checks?
May
5
accepted Security benefits of Ed25519 generating signatures deterministically
May
5
comment Security benefits of Ed25519 generating signatures deterministically
"I think there's a slight confusion there.... Diffie-Hellman" - yes, poorly worded.
May
5
revised Security benefits of Ed25519 generating signatures deterministically
added 56 characters in body
May
5
asked Security benefits of Ed25519 generating signatures deterministically
May
2
awarded  Teacher
Apr
24
comment CVE-2014-1295 (Apple's Secure Transport and Triple Handshake Attack)
Oh, OK. I thought I read about that some time ago. I guess the attack is more recent than I first thought...
Apr
24
accepted CVE-2014-1295 (Apple's Secure Transport and Triple Handshake Attack)
Apr
22
asked CVE-2014-1295 (Apple's Secure Transport and Triple Handshake Attack)