.\" $NetBSD: qsieve.1,v 1.2 2006/01/24 19:17:19 wiz Exp $
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.\" Copyright 1997, 2003 William Allen Simpson <wsimpson@greendragon.com>
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.\" Manual page, using -mandoc macros
.\"
.Dd July 28, 1997
.Dt QSIEVE 1
.Os
.Sh NAME
.Nm qsieve ,
.Nm qsafe
.Nd generate system moduli file
.Sh SYNOPSIS
.Nm
.Op Ar megabytes Ar bits Op Ar initial
.Nm qsafe
.Op Ar trials Op Ar generator
.Sh DESCRIPTION
The
.Nm
utility will list candidates for Sophie-Germaine primes
(where q = (p-1)/2)
to standard output.
The list is checked against small known primes
(less than 2**30).
This step is both processor and memory intensive.
.Pp
The
.Ar megabytes
value
sets a limit for the internal sieve buffer.
This should be small enough to remain entirely in memory.
Swap thrashing can increase the run time
from hours to days or weeks!
When the
.Ar megabytes
value is zero (0),
.Nm
will select a default suitable for the
.Ar bits .
.Pp
The
.Ar bits
value
sets the length of the generated possible primes
(typically 768, 1024, 1536, 2048, 3072, or 4096,
although others can be used for variety).
.Pp
The optional
.Ar initial
value (hex)
specifies the beginning of the search.
Otherwise,
.Nm
generates a randomly selected number.
.Pp
The
.Nm qsafe
utility will perform a Miller-Rabin primality test
on the list of candidates
(checking both q and p)
from standard input.
The result is a list of so-call "safe" primes
to standard output,
suitable for use as Diffie-Hellman moduli.
This step is merely processor intensive.
.Pp
The
.Ar trials
value
sets the number of Miller-Rabin interations
(typically 16 to 128).
.Pp
The optional
.Ar generator
value (hex)
limits testing to candidates with a specific generator
(usually 2).
Otherwise,
.Nm qsafe
will test each candidate
and suggest a generator.
.Sh SEE ALSO
.Xr moduli 5
.Sh HISTORY
These programs were originally developed for
the Photuris project,
and later
the OpenSSH project.