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Difference between revisions of "Insufficient Entropy"
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Many PRNG's (/dev/random and /dev/urandom for example) store their last value before shutdown. By using this value at intialization, they can sometimes avoid insufficient or predictable starting entropy. | Many PRNG's (/dev/random and /dev/urandom for example) store their last value before shutdown. By using this value at intialization, they can sometimes avoid insufficient or predictable starting entropy. | ||
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==Categories== | ==Categories== | ||
Revision as of 21:08, 12 February 2007
This is a Vulnerability. To view all vulnerabilities, please see the Vulnerability Category page.
Description
When an undesirably low amount of entropy is available. Psuedo Random Number Generators are susceptible to suffering from insufficient entropy when they are initialized because entropy data may not be available to them yet.
Examples
Related Threats
In many cases a PRNG uses a combination of the system clock and entropy to create seed data. In the case where insufficient entropy is available, an attacker can reduce the size magnitude of the seed value considerably. Furthermore, by guessing values of the system clock, they can create a manageable set of possible PRNG outputs.
Related Attacks
Related Vulnerabilities
Related Countermeasures
Many PRNG's (/dev/random and /dev/urandom for example) store their last value before shutdown. By using this value at intialization, they can sometimes avoid insufficient or predictable starting entropy.
Categories
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