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Questions tagged [isaac]

Questions about ISAAC stream cipher.

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Does ISAAC really guarantee a cycle length of at least 2**40?

I just noticed that the FSE 1996 conference paper which defines ISAAC mentions a counter variable cc. This variable is said to be the reason why ISAAC has a ...
Guenther Brunthaler's user avatar
2 votes
0 answers
69 views

Is ISAAC+ actually an improvement over ISAAC?

I just tried to implement ISAAC from scratch, using the Jean-Philippe Aumasson paper from 2007 as a reference. This paper gives a definition of the original ISAAC algorithm as well as the improved ...
Guenther Brunthaler's user avatar
1 vote
1 answer
77 views

Key scheduling for ISAAC

Does ISAAC use key scheduling? I do not know programming. Is it safe if ISAAC derives subkeys using ISAAC itself?
Mini kute's user avatar
2 votes
1 answer
216 views

Maximum security strength in bits of ISAAC cipher?

Wikipedia claims key length can be very big in this cipher, so I assume it can offer a million bits of security provided entropy of key is the same? Of course I can SHA-256 hash the key to allow any ...
Mini kute's user avatar
1 vote
0 answers
328 views

What is the purpose of ISAAC's randinit() function?

I am a relative crypto noob; please aim your answers accordingly. :) I'm planning to port the ISAAC CSPRNG algorithm to modern C++. I'm looking at Bob Jenkins' reference implementations: http://...
Quuxplusone's user avatar
2 votes
2 answers
129 views

Isaac nth number from run

Is there a way of getting the nth random number from a particular seed run in ISAAC? i.e. one day run a selection of 256 numbers and the next day run from the 256th number to get the next 256 random ...
Bipman's user avatar
  • 115
3 votes
1 answer
84 views

Is the output of ISAAC still secure if I take the 32 bit number mod 8?

I'm using ISAAC for encryption but only need an 8 bit number. So, if I use N mod 255, I presume the output would be only a random sequence of 255 numbers... but is ...
Bipman's user avatar
  • 115
4 votes
1 answer
1k views

Fast crytographically secure Pseudo-Random number generator in software

What are the methods for generating pseudo-random numbers in software? I have seen methods where people use SHA implementations from openssl to hash a random message as source of entropy, or using AES ...
Rick's user avatar
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3 votes
2 answers
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Why is ISAAC not a pseudo random number generator?

I have been accused of confusion over the nature of the ISAAC algorithm. The bulk of evidence suggests that it is a cryptographically strong pseudo random number generator. By bulk I mean the number ...
Paul Uszak's user avatar
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6 votes
1 answer
1k views

Is ISAAC Cipher Cryptographically Secure?

http://en.wikipedia.org/wiki/ISAAC_(cipher) This question was asked before but the answers seem vague, and I want to know about ISAAC specifically, not ISAAC+. It seems some cryptanalysis was ...
user3100783's user avatar
4 votes
1 answer
2k views

How secure is my OTP program?

I'm writing a one-time pad encryption program because I got really interested in the idea of "encryption which has been proven to be impossible to crack if used correctly". I'm writing the program ...
Janman's user avatar
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8 votes
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Is ISAAC considered secure as a cryptographic random number generator?

The ISAAC site claims it is secure, but I wasn't aware of any trusted 3rd party sources that verified its security.
Jim McKeeth's user avatar