Collaborate Disseminate
Math.random() produces a double value (IEEE 754 binary64) in the range [0.0, 1.0). How many digits (or bits) of entropy does the return value of random() contain?
If it simplifies things, I’m okay with assuming the distribut… Continue reading What is the entropy of a call to java.lang.Math.random()?
We all know that passwords should not only be randomly generated, but also look random. The reason is that attackers can use patterns or existing words to be able to bruteforce the passwords faster, so a randomly generated pa… Continue reading What should a secure passphrase look like?
William Kuszmaul published a study of an attack for RSA public keys on his blog https://algorithmsoup.wordpress.com/2019/01/15/breaking-an-unbreakable-code-part-1-the-hack/
The basic idea is, when people use poor PRNG to gen… Continue reading Does this attack on RSA keys reveals a major flaw, or this is no big deal with good entropy?
I want to make sure my password is very difficult to bruteforce but also easy to remember and convenient.
So my idea is to just use a short password and repeat it a few times like this:
Password654321Password654321Password6… Continue reading How much less secure is a password with a repetitive pattern of characters?
On successful authentcation, a web application issues a session cookie that is a constant length string of apparently random hex characters.
2E5F0FE4B7FCAB78CD967B46AB32915CCBFDC85316FAFB9174BDC4A3745339D8AD9C1D70A8EDD3D4F06… Continue reading Effects of new random Session token for each HTTP Request
I’m looking at this hashdump.py designed to extract macOS/OSX password hashes. But my Python isn’t great. I’m hoping someone can explain (or perhaps add comments to) some of the lines I’ve marked and explain what exactly is h… Continue reading Python: hashdump script for macOS/OSX
I’ve read the Chapter “Randomness” from the Serious Cryptography book and it raised some questions. Namely:
It is written that Mersenne Twister is proved to be cryptographically irreliable. And that is it used by some langua… Continue reading Pseudo-random generators and pitfalls
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 Ent… Continue reading 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 Ent… Continue reading rng-tools entropy sources
Let’s take, for example, Linux. From my understanding, there are different sources and different ways that can be used to gather entropy (RNG daemon, Intel rrandr, TPM, etc). Some produce entropy that is of “better quality” t… Continue reading For a "normal" computer user, does it make a difference to have a good entropy source?