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.
Questions tagged [entropy]
255 questions
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votes
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How was the concept of password entropy developed?
I understand how to calculate password entropy and what the Length and Character values represent. I also have a reasonable understanding of other types of entropy (e.g. Shannon). However, password entropy seems to be considerably different (in…
Aengus
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How can I measure (and increase) entropy on Mac OS X?
I'd like to generate a bunch of keys for long term storage on my MacBook.
What's a good way to:
measure the amount of entropy and ensure it is sufficient before each key is generated, and
increase the entropy if needed?
Something similar to…
Brian Armstrong
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5
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Credit card number entropy?
I want to confirm that this understanding is correct:
A card has 16 digits plus a CV2
The first 6 digits are an issuer identification number
The last digit of the 16 is a Luhn mod 10 check digit.
This leaves 9 digits in the middle.
Are these 9…
Cris
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5
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Approximately how much entropy in each of these low entropy sources?
We need a lot of entropy. Let's be a little unrealistic and assume that we don't have access to entropy pools like dev/random, and must do all the entropy collection ourselves. The program is running on a user's computer, but they may not allow us…
EPICI
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rng-tools entropy sources
Using rng-tools 6.3.1, I list the entropy sources:
$ rngd -l
Entropy sources that are available but disabled
4: NIST Network Entropy Beacon
Available and enabled entropy sources:
2: Intel RDRAND Instruction RNG
5: JITTER Entropy generator
What…
Antick
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2
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Why is /dev/random so slow on Linux?
If it's true you only need about 128 bits of entropy to fuel enough data forever, why is it that /dev/random is so slow? My system has uptime of 214 days!
Is it really only gathering .000000001 bits of entropy every sample? Shouldn't a mere jitter…
Blaze
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Is this password entropy calculation correct?
I'm trying to compute the entropy of a passphrase of the following pattern:
.... .... .... ....
Where . represent lowercase characters.
The passphrase follows the rule that the two parts of each 4-character sequence have a vowel and a consonant,…
user103579
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vote
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Entropy in Address Randomization
I am trying to understand the concept behind address randomization (ASLR). I'm reading the related wikipedia article which states:
Security is increased by increasing the search space. Thus,
address space randomization is more effective when more…
Jake
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