Man Linux: Main Page and Category List


       ipsec_ranbits - generate random bits in ASCII form


       ipsec ranbits [--quick] [--continuous] [--bytes] nbits


       Ranbits obtains nbits (rounded up to the nearest byte) high-quality
       random bits from random(4), and emits them on standard output as an
       ASCII string. The default output format is datatot(3) h format:
       lowercase hexadecimal with a 0x prefix and an underscore every 32 bits.

       The --quick option produces quick-and-dirty random bits: instead of
       using the high-quality random bits from /dev/random, which may take
       some time to supply the necessary bits if nbits is large, ranbits uses
       /dev/urandom, which yields prompt results but lower-quality randomness.

       The --continuous option uses datatot(3) x output format, like h but
       without the underscores.

       The --bytes option causes nbits to be interpreted as a byte count
       rather than a bit count.


       /dev/random, /dev/urandom


       ipsec_datatot(3), random(4)


       Written for the Linux FreeS/WAN project <> by
       Henry Spencer.


       There is an internal limit on nbits, currently 20000.

       Without --quick, ranbits’s run time is difficult to predict. A request
       for a large number of bits, at a time when the system’s entropy pool is
       low on randomness, may take quite a while to satisfy.

       Though not a bug of ranbits, the direct use of /dev/hw_random, the
       Linux hardware random number generator is not supported because it can
       produce very non-random data. To properly use /dev/hw_random, the rngd
       daemon should be used to read from /dev/hw_random and write to
       /dev/random, while performing a FIPS test on the hardware random read.
       No changes to Openswan are required for this support - just a running