PingAuthorize

Managing system entropy

Entropy is used to calculate random data that the system uses in cryptographic operations.

About this task

Some environments with low entropy might experience intermittent performance issues with SSL-based communication, such as certificate generation. This scenario is more typical on virtual machines but can also occur in physical instances. For best results, monitor the value of kernel.random.entropy_avail in the configuration file /etc/sysctl.conf.

To increase system entropy on a Windows system, move the mouse pointer in circles or type characters randomly into an empty text document.

Steps

  • On a UNIX or Linux system, ensure that rng-tools is installed and run the following command.

    sudo rngd -r /dev/urandom -o /dev/random

  • To check the level of a system entropy on a UNIX or Linux system, run the following command.

    cat /proc/sys/kernel/random/entropy_avail

    Values smaller than 3200 are considered too low to generate a certificate and might cause the system to hang indefinitely.