1IPSEC_RANBITS(8)                                              IPSEC_RANBITS(8)
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NAME

6       ipsec ranbits - generate random bits in ASCII form
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SYNOPSIS

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

13       Ranbits  obtains  nbits  (rounded  up to the nearest byte) high-quality
14       random bits from random(4), and emits them on  standard  output  as  an
15       ASCII string. The default output format is datatot(3)  h format: lower‐
16       case hexadecimal with a 0x prefix and an underscore every 32 bits.
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19       The --quick option produces quick-and-dirty random bits: instead of us‐
20       ing  the high-quality random bits from /dev/random, which may take some
21       time to supply the necessary bits  if  nbits  is  large,  ranbits  uses
22       /dev/urandom, which yields prompt results but lower-quality randomness.
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25       The  --continuous  option  uses datatot(3)  x output format, like h but
26       without the underscores.
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29       The --bytes option causes nbits to  be  interpreted  as  a  byte  count
30       rather than a bit count.
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FILES

34       /dev/random, /dev/urandom
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SEE ALSO

38       ipsec_datatot(3), random(4)
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HISTORY

42       Written  for  the  Linux  FreeS/WAN  project  <http://www.freeswan.org:
43       http://www.freeswan.org> by Henry Spencer.
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BUGS

47       There is an internal limit on nbits, currently 20000.
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50       Without --quick, ranbits's run time is difficult to predict. A  request
51       for a large number of bits, at a time when the system's entropy pool is
52       low on randomness, may take quite a while to satisfy.
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55       Though not a bug of ranbits, the direct use of /dev/hw_random, the Lin‐
56       ux  hardware  random  number  generator is not supported because it can
57       produce very non-random data. To properly use /dev/hw_random, the  rngd
58       daemon  should  be  used  to  read  from  /dev/hw_random  and  write to
59       /dev/random, while performing a FIPS test on the hardware random  read.
60       No  changes  to Openswan are required for this support - just a running
61       rngd.
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66                                                              IPSEC_RANBITS(8)