QSIEVE(1)

NAME
qsieve, qsafe - generate system moduli file

SYNOPSIS
qsieve [megabytes bits [initial]]
qsafe [trials [generator]]

DESCRIPTION
The qsieve 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.

The 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 megabytes value is zero (0), qsieve will select a default suitable for the bits.

The 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).

The optional initial value (hex) specifies the beginning of the search. Otherwise, qsieve generates a randomly selected number.

The 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.

The trials value sets the number of Miller-Rabin interations (typically 16 to 128).

The optional generator value (hex) limits testing to candidates with a specific generator (usually 2). Otherwise, qsafe will test each candidate and suggest a generator.

SEE ALSO
moduli(5)

HISTORY
These programs were originally developed for the Photuris project, and later the OpenSSH project.