/dev/random
Purpose
The file /dev/random provides random data from the Linux kernel random number generator. Typically /dev/urandom is the preferred source for random data.
This file on Linux is a filesystem interface to an operating system device driver of type character.
Usually /dev/random is created during the boot cycle using the mknod command. The random numbers provided are generated from an entropy pool that is filled using noise such as from device drivers. The underlying random functions also track the number of bits in the entropy pool, and may give a warning if it is not sufficient.
File permissions
Usually the /dev/random file will have the permissions of 666 (rw-rw-rw-), meaning user, group, and others can read and write.
More information and usage of /dev/random
The following articles have a reference to /dev/random and might be worth reading to learn more.