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ehtan
Jan 07, 2013

What is an entropy pool used for?

There is an Android app called Seeder that claims to reduce lag by ensuring that the entropy pool is constantly filled. Ok, but what is an entropy pool and what is it used for?

jimlynch
01/15/2013
Here's an article about entropy possibly slowing down Android devices:

Is entropy slowing down your Android device?
http://hackaday.com/2013/01/04/is-entropy-slowing-down-your-android-devi...
landon
01/08/2013

It's basically a pool of random numbers that operates at the kernel level. There is a huge debate going on in among android developers about whether the Seeder apk has an effect or not. It seems that on newer quad-core devices there is little or no benefit noticed. On older, less powerful devices people seem to notice an improvement. Unfortunately, pretty much everything offered has been subjective.  I followed the thread over at xda for the 1st 150 pages, but I've slacked off today.

Google's developers says it doesn't do anything (except perhaps for 2.2 or older versions of Android), and that dev/random (entropy pool) is only used for cryptography operations.  Here is the thing though, when the entropy pool is monitored, it DOES decline over time, so SOMETHING is causing that to happen. Also, WPA2 uses dev/random, unless I am mistaken, so perhaps it would make a difference when using a WiFi connection but not 3G/4G. Or perhaps not.

Oh, to save passerby readers the time of going looking for Seeder - you can ONLY try it if you are rooted.

C
Christopher Nerney
01/08/2013

 

An entropy pool is part of a security system designed to protect a computer from malicious attackers. From Wikipedia:

 

"With sufficient care, a system can be designed that produces cryptographically secure random numbers from the sources of randomness available in a modern computer. The basic design is to maintain an "entropy pool" of random bits that are assumed to be unknown to an attacker. New randomness is added whenever available (for example, when the user hits a key) and an estimate of the number of bits in the pool that cannot be known to an attacker is kept."

 

If an entropy pool isn't full, according to this site, programs that need entropy "just 'hang' and wait for more to be created. That's apparently what Seeder is designed to avoid.

 

 

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