NetBSD-5.0.2/lib/libcrypto/man/RSA_check_key.3
.\" $NetBSD: RSA_check_key.3,v 1.20 2008/05/09 22:02:43 christos Exp $
.\"
.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings. \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote. | will give a
.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used to
.\" do unbreakable dashes and therefore won't be available. \*(C` and \*(C'
.\" expand to `' in nroff, nothing in troff, for use with C<>.
.tr \(*W-|\(bv\*(Tr
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.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" ""
. ds C` ""
. ds C' ""
'br\}
.el\{\
. ds -- \|\(em\|
. ds PI \(*p
. ds L" ``
. ds R" ''
'br\}
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD. Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.if \nF \{\
. de IX
. tm Index:\\$1\t\\n%\t"\\$2"
..
. nr % 0
. rr F
.\}
.\"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear. Run. Save yourself. No user-serviceable parts.
. \" 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 /
.\}
.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 / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
. \" 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 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
. \" 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 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
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "RSA_check_key 3"
.TH RSA_check_key 3 "2003-07-24" "0.9.9-dev" "OpenSSL"
.SH "NAME"
RSA_check_key \- validate private RSA keys
.SH "LIBRARY"
libcrypto, -lcrypto
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/rsa.h>
.Ve
.PP
.Vb 1
\& int RSA_check_key(RSA *rsa);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This function validates \s-1RSA\s0 keys. It checks that \fBp\fR and \fBq\fR are
in fact prime, and that \fBn = p*q\fR.
.PP
It also checks that \fBd*e = 1 mod (p\-1*q\-1)\fR,
and that \fBdmp1\fR, \fBdmq1\fR and \fBiqmp\fR are set correctly or are \fB\s-1NULL\s0\fR.
.PP
As such, this function can not be used with any arbitrary \s-1RSA\s0 key object,
even if it is otherwise fit for regular \s-1RSA\s0 operation. See \fB\s-1NOTES\s0\fR for more
information.
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
\&\fIRSA_check_key()\fR returns 1 if \fBrsa\fR is a valid \s-1RSA\s0 key, and 0 otherwise.
\&\-1 is returned if an error occurs while checking the key.
.PP
If the key is invalid or an error occurred, the reason code can be
obtained using \fIERR_get_error\fR\|(3).
.SH "NOTES"
.IX Header "NOTES"
This function does not work on \s-1RSA\s0 public keys that have only the modulus
and public exponent elements populated. It performs integrity checks on all
the \s-1RSA\s0 key material, so the \s-1RSA\s0 key structure must contain all the private
key data too.
.PP
Unlike most other \s-1RSA\s0 functions, this function does \fBnot\fR work
transparently with any underlying \s-1ENGINE\s0 implementation because it uses the
key data in the \s-1RSA\s0 structure directly. An \s-1ENGINE\s0 implementation can
override the way key data is stored and handled, and can even provide
support for \s-1HSM\s0 keys \- in which case the \s-1RSA\s0 structure may contain \fBno\fR
key data at all! If the \s-1ENGINE\s0 in question is only being used for
acceleration or analysis purposes, then in all likelihood the \s-1RSA\s0 key data
is complete and untouched, but this can't be assumed in the general case.
.SH "BUGS"
.IX Header "BUGS"
A method of verifying the \s-1RSA\s0 key using opaque \s-1RSA\s0 \s-1API\s0 functions might need
to be considered. Right now \fIRSA_check_key()\fR simply uses the \s-1RSA\s0 structure
elements directly, bypassing the \s-1RSA_METHOD\s0 table altogether (and
completely violating encapsulation and object-orientation in the process).
The best fix will probably be to introduce a \*(L"\fIcheck_key()\fR\*(R" handler to the
\&\s-1RSA_METHOD\s0 function table so that alternative implementations can also
provide their own verifiers.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIopenssl_rsa\fR\|(3), \fIERR_get_error\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIRSA_check_key()\fR appeared in OpenSSL 0.9.4.