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 <http://www.freeswan.org> 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. |