Please can someone explain the function of the wpa_supplicant entropy file passed with the -e option.
Thanks
Edit:
Okay I found this in the source code
# wpa_supplicant depends on strong random number generation being available
# from the operating system. os_get_random() function is used to fetch random
# data when needed, e.g., for key generation. On Linux and BSD systems, this
# works by reading /dev/urandom. It should be noted that the OS entropy pool
# needs to be properly initialized before wpa_supplicant is started. This is
# important especially on embedded devices that do not have a hardware random
# number generator and may by default start up with minimal entropy available
# for random number generation.
#
# As a safety net, wpa_supplicant is by default trying to internally collect
# additional entropy for generating random data to mix in with the data fetched
# from the OS. This by itself is not considered to be very strong, but it may
# help in cases where the system pool is not initialized properly. However, it
# is very strongly recommended that the system pool is initialized with enough
# entropy either by using hardware assisted random number generator or by
# storing state over device reboots.
#
# wpa_supplicant can be configured to maintain its own entropy store over
# restarts to enhance random number generation. This is not perfect, but it is
# much more secure than using the same sequence of random numbers after every
# reboot. This can be enabled with -e<entropy file> command line option. The
# specified file needs to be readable and writable by wpa_supplicant.
#
# If the os_get_random() is known to provide strong random data (e.g., on
# Linux/BSD, the board in question is known to have reliable source of random
# data from /dev/urandom), the internal wpa_supplicant random pool can be
# disabled. This will save some in binary size and CPU use. However, this
# should only be considered for builds that are known to be used on devices
# that meet the requirements described above.
Thanks
Edit:
Okay I found this in the source code
# wpa_supplicant depends on strong random number generation being available
# from the operating system. os_get_random() function is used to fetch random
# data when needed, e.g., for key generation. On Linux and BSD systems, this
# works by reading /dev/urandom. It should be noted that the OS entropy pool
# needs to be properly initialized before wpa_supplicant is started. This is
# important especially on embedded devices that do not have a hardware random
# number generator and may by default start up with minimal entropy available
# for random number generation.
#
# As a safety net, wpa_supplicant is by default trying to internally collect
# additional entropy for generating random data to mix in with the data fetched
# from the OS. This by itself is not considered to be very strong, but it may
# help in cases where the system pool is not initialized properly. However, it
# is very strongly recommended that the system pool is initialized with enough
# entropy either by using hardware assisted random number generator or by
# storing state over device reboots.
#
# wpa_supplicant can be configured to maintain its own entropy store over
# restarts to enhance random number generation. This is not perfect, but it is
# much more secure than using the same sequence of random numbers after every
# reboot. This can be enabled with -e<entropy file> command line option. The
# specified file needs to be readable and writable by wpa_supplicant.
#
# If the os_get_random() is known to provide strong random data (e.g., on
# Linux/BSD, the board in question is known to have reliable source of random
# data from /dev/urandom), the internal wpa_supplicant random pool can be
# disabled. This will save some in binary size and CPU use. However, this
# should only be considered for builds that are known to be used on devices
# that meet the requirements described above.