The generation of random or pseudorandom data, and the use of randomness in security protocols

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What are the pitfalls while generating a random number from a random data set?

I am relatively new to the GPG key system and I have been been learning about the system through experimentation. I now know that while generating a random seed for the key generation, the random ...
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4answers
164 views

pesudo random password

I post a question before about one password repeating to make it longer, now its a new way want to ask about, if take the word 'secure' and instead of repeating it put somenumbers between it, exp: ...
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2answers
221 views

What to consider when generating random code as part of two-factor authentication?

I want to write a patch for a two factor authentication system that someone else has started. The code is a module for a PHP content management system and sends an SMS message to a user's phone, after ...
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4answers
5k views

What are you doing when you move your mouse randomly during a truecrypt volume creation?

Is that called a 'round' every time you move your mouse when creating a new volume? I'm talking about the screen with the random numbers during the volume creation process. What is the purpose of ...
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2answers
230 views

What factors increase the probability of duplicating a GUID?

It's been argued that a GUID doesn't do a good job of being a one time security token , and it makes sense because GUIDs aren't random. In my scenario: suppose a given company is using GUIDs as a ...
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Can the numbers on RSA SecurID tokens be predicted?

My workplace uses these SecurID tokens which provide you with a temporary password, the code will expire after a short time. I have always been fascinated by the things, because it seems as though ...
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1answer
651 views

Should I include a random padding in every HTTPS request and response?

According to the following paper, it is possible to decrypt HTTPS traffic by inspecting AJAX calls and using the size parameter as a cryptographic oracle. Should I be sending a variable length ...
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1answer
2k views

OpenSSL RAND_poll 'good enough'

We are using OpenSSL for generating IV's and other random data. We initialize it using RAND_poll and, on Windows, RAND_screen. The question is though, if the seed generated by those methods is good ...
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1answer
288 views

Random number for HTTPS Message Authentication Code (MAC)

Recently I found that Netscape used quite simple algorithm to generate random number for Message Authentication Code to establish an HTTPS connection (Netscape used time, process identification ...
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3answers
1k views

Cryptographic Security of Dynamically Generated, Non-Random Salts

So when it comes to security, when I have an idea that seems good, but no one else seems to be doing, I try to assume that I'm overlooking something obvious or otherwise significant. This is one such ...
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2answers
2k views

/dev/random security holes

I'm doing some reading into the security issues surrounding /dev/random but it's proving to be hard to find good sources of information. Can anybody help? I've asked Google and got a bunch of articles ...
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Flaw in encryption through pseudorandom number stream (from PGP documentation)

I was reading PGP docs and came upon a part written by Phil Zimmermann (PGP's creator) that piqued my curiosity: When I was in college in the early 70s, I devised what I believed was a brilliant ...
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5answers
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Should passwords be truly random?

When generating a password, should it be "truly random" or should I make it a little less random by enforcing some rules? If a password is generated at random, it could come out all-lowercase letters ...
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2answers
1k views

Is this algorithm for a random string cryptographically secure?

I've pieced together this algorithm (if it can be called that) from various bits of code I've seen online, and I'm wondering how cryptographically secure it is. It's used to generate passwords: ...
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2answers
4k views

Is “real salt” the same as “initialization vectors”?

In the question about real vs. fake salt, the answers describe how real salt 'perturbs the encryption algorithm.' I know roughly how initialization vectors work; is this the same concept, or something ...
4
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1answer
427 views

Asynchonous Linear Feedback Shift Register : test vectors

Well I've been working on coding LFSR structures for my research projects. Being able to find sources on the subject, I've been able to test a single LFSR with different initialisation and TAP ...
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2answers
624 views

Is a rand from glibc's rand secure for a login key?

Same question as Is a rand from /dev/urandom secure for a login key, but with glibc's rand function instead of /dev/urandom. And what would be a sufficiently secure seed generator?
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4answers
2k views

Using computer random number generators to produce keys, it is secure?

Does generating an encryption key using the random number generator on one's computer present a security risk? If so how might that risk be mitigated, specifically when generating RSA key pairs in ...
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2answers
5k views

Cracking a linear congruential generator

I was recently listening to the security now podcast, and they mentioned in passing that the linear congrunential generator (LCG) is trivial to crack. I use the LCG in a first year stats computing ...
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3answers
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Is a rand from /dev/urandom secure for a login key?

Lets say I want to create a cookie for a user. Would simply generating a 1024 bit string by using /dev/urandom, and checking if it already exists (looping until I get a unique one) suffice? Or should ...
8
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1answer
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Howto seed the PRNG in OpenSSL properly?

I am creating an application which runs on a mobile node with Ubuntu, which does not generate enough entropy bytes to the /dev/random, and does not always stay connected on the Internet to use typical ...
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2answers
1k views

Evaluating the entropy gathering in a PRNG

I'm reviewing the random number generator (expected to be of cryptographic quality) on an embedded device. My point of view here is the operating system and crypto library implementer. I'm ...
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3answers
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License key / Serial number generator and checker

I need a serial number generator and accompanying checker. I would like to be able to set a salt (and maybe a length). The generator should only produce serial numbers that pass the test of the ...
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5answers
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Do mobile OS's provide crypto-quality randomness?

Which mobile OS's provide a primitive to generate crypto-quality randomness that applications can use? On desktop systems, these features are pervasive. Unix provides /dev/urandom. Windows provides ...
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3answers
5k views

How long should a random nonce be?

NIST provides good guidelines on the length of keys and hashes for various algorithms. But I don't see anything specifically on the length of a random or pseudo-random nonce (number used once). If ...
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5answers
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Are GUIDs safe for one-time tokens?

I see a lot of sites use GUIDs for password resets, unsubscribe requests and other forms of unique identification. Presumably they are appealing because they are easy to generate, unique, ...
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Feeding /dev/random entropy pool?

Which way of additionally feeding /dev/random entropy pool would you suggest for producing random passwords? Or, is there maybe a better way to locally create fully random passwords?