Commit manual pages after running 'man-update' and add new manual pages.

[dragonfly.git] / secure / lib / libcrypto / man / DH_generate_parameters.3

.rn '' }`
''' $RCSfile$$Revision$$Date$
'''
''' $Log$
'''
.de Sh
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp
.if t .sp .5v
.if n .sp
..
.de Ip
.br
.ie \\n(.$>=3 .ne \\$3
.el .ne 3
.IP "\\$1" \\$2
..
.de Vb
.ft CW
.nf
.ne \\$1
..
.de Ve
.ft R

.fi
..
'''
'''
'''     Set up \*(-- to give an unbreakable dash;
'''     string Tr holds user defined translation string.
'''     Bell System Logo is used as a dummy character.
'''
.tr \(*W-|\(bv\*(Tr
.ie n \{\
.ds -- \(*W-
.ds PI pi
.if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
.ds L" ""
.ds R" ""
'''   \*(M", \*(S", \*(N" and \*(T" are the equivalent of
'''   \*(L" and \*(R", except that they are used on ".xx" lines,
'''   such as .IP and .SH, which do another additional levels of
'''   double-quote interpretation
.ds M" """
.ds S" """
.ds N" """""
.ds T" """""
.ds L' '
.ds R' '
.ds M' '
.ds S' '
.ds N' '
.ds T' '
'br\}
.el\{\
.ds -- \(em\|
.tr \*(Tr
.ds L" ``
.ds R" ''
.ds M" ``
.ds S" ''
.ds N" ``
.ds T" ''
.ds L' `
.ds R' '
.ds M' `
.ds S' '
.ds N' `
.ds T' '
.ds PI \(*p
'br\}
.\"	If the F register is turned on, we'll generate
.\"	index entries out stderr for the following things:
.\"		TH	Title 
.\"		SH	Header
.\"		Sh	Subsection 
.\"		Ip	Item
.\"		X<>	Xref  (embedded
.\"	Of course, you have to process the output yourself
.\"	in some meaninful fashion.
.if \nF \{
.de IX
.tm Index:\\$1\t\\n%\t"\\$2"
..
.nr % 0
.rr F
.\}
.TH DH_generate_parameters 3 "0.9.7d" "2/Sep/2004" "OpenSSL"
.UC
.if n .hy 0
.if n .na
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.de CQ          \" put $1 in typewriter font
.ft CW
'if n "\c
'if t \\&\\$1\c
'if n \\&\\$1\c
'if n \&"
\\&\\$2 \\$3 \\$4 \\$5 \\$6 \\$7
'.ft R
..
.\" @(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2
.	\" AM - accent mark definitions
.bd B 3
.	\" fudge factors for nroff and troff
.if n \{\
.	ds #H 0
.	ds #V .8m
.	ds #F .3m
.	ds #[ \f1
.	ds #] \fP
.\}
.if t \{\
.	ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.	ds #V .6m
.	ds #F 0
.	ds #[ \&
.	ds #] \&
.\}
.	\" simple accents for nroff and troff
.if n \{\
.	ds ' \&
.	ds ` \&
.	ds ^ \&
.	ds , \&
.	ds ~ ~
.	ds ? ?
.	ds ! !
.	ds /
.	ds q
.\}
.if t \{\
.	ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.	ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.	ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.	ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.	ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.	ds ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10'
.	ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m'
.	ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.	ds q o\h'-\w'o'u*8/10'\s-4\v'.4m'\z\(*i\v'-.4m'\s+4\h'\w'o'u*8/10'
.\}
.	\" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(#]
.ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u'
.ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u'
.ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#]
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.ds oe o\h'-(\w'o'u*4/10)'e
.ds Oe O\h'-(\w'O'u*4/10)'E
.	\" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.	\" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.	ds : e
.	ds 8 ss
.	ds v \h'-1'\o'\(aa\(ga'
.	ds _ \h'-1'^
.	ds . \h'-1'.
.	ds 3 3
.	ds o a
.	ds d- d\h'-1'\(ga
.	ds D- D\h'-1'\(hy
.	ds th \o'bp'
.	ds Th \o'LP'
.	ds ae ae
.	ds Ae AE
.	ds oe oe
.	ds Oe OE
.\}
.rm #[ #] #H #V #F C
.SH "NAME"
DH_generate_parameters, DH_check \- generate and check Diffie-Hellman parameters
.SH "SYNOPSIS"
.PP
.Vb 1
\& #include <openssl/dh.h>
.Ve
.Vb 2
\& DH *DH_generate_parameters(int prime_len, int generator,
\&     void (*callback)(int, int, void *), void *cb_arg);
.Ve
.Vb 1
\& int DH_check(DH *dh, int *codes);
.Ve
.SH "DESCRIPTION"
\fIDH_generate_parameters()\fR generates Diffie-Hellman parameters that can
be shared among a group of users, and returns them in a newly
allocated \fBDH\fR structure. The pseudo-random number generator must be
seeded prior to calling \fIDH_generate_parameters()\fR.
.PP
\fBprime_len\fR is the length in bits of the safe prime to be generated.
\fBgenerator\fR is a small number > 1, typically 2 or 5. 
.PP
A callback function may be used to provide feedback about the progress
of the key generation. If \fBcallback\fR is not \fBNULL\fR, it will be
called as described in BN_generate_prime(3) while a random prime
number is generated, and when a prime has been found, \fBcallback(3,
0, cb_arg)\fR is called.
.PP
\fIDH_check()\fR validates Diffie-Hellman parameters. It checks that \fBp\fR is
a safe prime, and that \fBg\fR is a suitable generator. In the case of an
error, the bit flags DH_CHECK_P_NOT_SAFE_PRIME or
DH_NOT_SUITABLE_GENERATOR are set in \fB*codes\fR.
DH_UNABLE_TO_CHECK_GENERATOR is set if the generator cannot be
checked, i.e. it does not equal 2 or 5.
.SH "RETURN VALUES"
\fIDH_generate_parameters()\fR returns a pointer to the DH structure, or
NULL if the parameter generation fails. The error codes can be
obtained by ERR_get_error(3).
.PP
\fIDH_check()\fR returns 1 if the check could be performed, 0 otherwise.
.SH "NOTES"
\fIDH_generate_parameters()\fR may run for several hours before finding a
suitable prime.
.PP
The parameters generated by \fIDH_generate_parameters()\fR are not to be
used in signature schemes.
.SH "BUGS"
If \fBgenerator\fR is not 2 or 5, \fBdh->g\fR=\fBgenerator\fR is not
a usable generator.
.SH "SEE ALSO"
dh(3), ERR_get_error(3), rand(3),
DH_free(3)
.SH "HISTORY"
\fIDH_check()\fR is available in all versions of SSLeay and OpenSSL.
The \fBcb_arg\fR argument to \fIDH_generate_parameters()\fR was added in SSLeay 0.9.0.
.PP
In versions before OpenSSL 0.9.5, DH_CHECK_P_NOT_STRONG_PRIME is used
instead of DH_CHECK_P_NOT_SAFE_PRIME.

.rn }` ''
.IX Title "DH_generate_parameters 3"
.IX Name "DH_generate_parameters, DH_check - generate and check Diffie-Hellman parameters"

.IX Header "NAME"

.IX Header "SYNOPSIS"

.IX Header "DESCRIPTION"

.IX Header "RETURN VALUES"

.IX Header "NOTES"

.IX Header "BUGS"

.IX Header "SEE ALSO"

.IX Header "HISTORY"