Feeding /dev/random entropy pool?


– Feeding the /dev/random entropy pool is important for maintaining system security.
– This can be done through a variety of methods, including hardware devices and software tools.
– Proper implementation of these methods is critical to ensure that the entropy pool remains secure.

– Main body:
1. Introduction
– The /dev/random device provides random numbers that are used for cryptographic purposes, such as generating encryption keys.
– However, its output can be limited if there is not enough entropy in the system’s entropy pool.
– This can lead to a situation where /dev/random blocks and prevents further generation of random numbers, potentially compromising system security.
2. Importance of feeding the entropy pool
– The entropy pool is used by the operating system to generate random numbers that are used for various purposes, including encryption and authentication.
– A lack of sufficient entropy can lead to predictable output from /dev/random, which can be exploited by attackers to break encryption or perform other malicious activities.
3. Methods for feeding the entropy pool
1. Hardware devices:
– Some hardware devices, such as USB tokens and random number generators, can provide additional entropy to the system.
– These devices typically have dedicated hardware for generating random numbers and can be connected directly to the computer’s USB port or other interface.
2. Software tools:
– There are various software tools available that can help feed the entropy pool by collecting and injecting randomness from various sources, such as mouse movements and keystrokes.
– Some popular tools include haveged, rng-tools, and entropyd.
4. Best practices for feeding the entropy pool
1. Use multiple methods:
– Combining hardware devices and software tools can provide a more diverse and robust source of entropy.
– This helps to prevent attacks that target a single source of entropy and increases the overall security of the system.
2. Monitor the entropy level:
– Regularly check the system’s entropy level using tools such as /proc/sys/kernel/random/entropy_avail or /dev/urandom.
– If the entropy level is low, take steps to increase it by feeding the entropy pool with additional sources of randomness.
3. Disable predictable sources of entropy:
– Some sources of entropy can be easily predicted, such as the system clock and CPU timers.
– Disabling these sources can reduce the likelihood of attacks that exploit predictability in the entropy pool.


– Feeding the /dev/random entropy pool is essential for maintaining system security by ensuring that cryptographic operations are not compromised.
– A variety of methods, including hardware devices and software tools, can be used to increase the amount of entropy in the system’s pool.
– Proper implementation of these methods, such as using multiple sources of entropy and disabling predictable sources, is critical for ensuring the security of the system.

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