What you are saying is spot on. Yes, theoretically it is possible to feed entropy into /dev/random, but you’d need to control a lot of the kernel “noise” sources for it to be significant. You can look at the source for random.c, to see where /dev/random picks up noise from. Basically, if you control a … Read more
Entropy is not a property of the string you got, but of the strings you could have obtained instead. In other words, it qualifies the process by which the string was generated. In the simple case, you get one string among a set of N possible strings, where each string has the same probability of … Read more
Entropy can mean different things: Computing In computing, entropy is the randomness collected by an operating system or application for use in cryptography or other uses that require random data. This randomness is often collected from hardware sources, either pre-existing ones such as mouse movements or specially provided randomness generators. Information theory In information theory, … Read more
@Sanjeet Gupta answer is good but could be condensed. This question is specifically asking about the “Fastest” way but I only see times on one answer so I’ll post a comparison of using scipy and numpy to the original poster’s entropy2 answer with slight alterations. Four different approaches: (1) scipy/numpy, (2) numpy/math, (3) pandas/numpy, (4) … Read more
Run the following: find / > /dev/null That helped me quickly to complete my key generation.
At the end: Calculate the “average” value for the array. Initialize a counter with zero, and for each of the array’s entries: add the entry’s difference to “average” to the counter. With some modifications you can get Shannon’s entropy: rename “average” to “entropy” (float) entropy = 0 for i in the array[256]:Counts do (float)p = … Read more
243,583,606,221,817,150,598,111,409x more entropy I’d recommend using crypto.randomBytes. It’s not sha1, but for id purposes, it’s quicker, and just as “random”. var id = crypto.randomBytes(20).toString(‘hex’); //=> f26d60305dae929ef8640a75e70dd78ab809cfe9 The resulting string will be twice as long as the random bytes you generate; each byte encoded to hex is 2 characters. 20 bytes will be 40 characters of … Read more
You should be able to select the faster-but-slightly-less-secure /dev/urandom on Linux using: -Djava.security.egd=file:/dev/urandom However, this doesn’t work with Java 5 and later (Java Bug 6202721). The suggested work-around is to use: -Djava.security.egd=file:/dev/./urandom (note the extra /./)