NetBSD/lib/libcrypto/man/PKCS7_encrypt.3

.\"	$NetBSD: PKCS7_encrypt.3,v 1.2 2004/03/20 21:48:46 groo Exp $
.\"
.\" Automatically generated by Pod::Man version 1.15
.\" Sat Mar 20 16:41:02 2004
.\"
.\" 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 Ip \" List item
.br
.ie \\n(.$>=3 .ne \\$3
.el .ne 3
.IP "\\$1" \\$2
..
.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.
.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 /
.\}
.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 "PKCS7_encrypt 3"
.TH PKCS7_encrypt 3 "0.9.7d" "2003-07-24" "OpenSSL"
.UC
.SH "NAME"
PKCS7_encrypt \- create a PKCS#7 envelopedData structure
.SH "LIBRARY"
libcrypto, -lcrypto
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\s-1PKCS7\s0 *PKCS7_encrypt(STACK_OF(X509) *certs, \s-1BIO\s0 *in, const \s-1EVP_CIPHER\s0 *cipher, int flags);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fIPKCS7_encrypt()\fR creates and returns a PKCS#7 envelopedData structure. \fBcerts\fR
is a list of recipient certificates. \fBin\fR is the content to be encrypted.
\&\fBcipher\fR is the symmetric cipher to use. \fBflags\fR is an optional set of flags.
.SH "NOTES"
.IX Header "NOTES"
Only \s-1RSA\s0 keys are supported in PKCS#7 and envelopedData so the recipient certificates
supplied to this function must all contain \s-1RSA\s0 public keys, though they do not have to
be signed using the \s-1RSA\s0 algorithm.
.PP
\&\fIEVP_des_ede3_cbc()\fR (triple \s-1DES\s0) is the algorithm of choice for S/MIME use because
most clients will support it.
.PP
Some old \*(L"export grade\*(R" clients may only support weak encryption using 40 or 64 bit
\&\s-1RC2\s0. These can be used by passing \fIEVP_rc2_40_cbc()\fR and \fIEVP_rc2_64_cbc()\fR respectively.
.PP
The algorithm passed in the \fBcipher\fR parameter must support \s-1ASN1\s0 encoding of its
parameters. 
.PP
Many browsers implement a \*(L"sign and encrypt\*(R" option which is simply an S/MIME 
envelopedData containing an S/MIME signed message. This can be readily produced
by storing the S/MIME signed message in a memory \s-1BIO\s0 and passing it to
\&\fIPKCS7_encrypt()\fR.
.PP
The following flags can be passed in the \fBflags\fR parameter.
.PP
If the \fB\s-1PKCS7_TEXT\s0\fR flag is set \s-1MIME\s0 headers for type \fBtext/plain\fR are prepended
to the data.
.PP
Normally the supplied content is translated into \s-1MIME\s0 canonical format (as required
by the S/MIME specifications) if \fB\s-1PKCS7_BINARY\s0\fR is set no translation occurs. This
option should be used if the supplied data is in binary format otherwise the translation
will corrupt it. If \fB\s-1PKCS7_BINARY\s0\fR is set then \fB\s-1PKCS7_TEXT\s0\fR is ignored.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIPKCS7_encrypt()\fR returns either a valid \s-1PKCS7\s0 structure or \s-1NULL\s0 if an error occurred.
The error can be obtained from \fIERR_get_error\fR\|(3).
.SH "BUGS"
.IX Header "BUGS"
The lack of single pass processing and need to hold all data in memory as
mentioned in \fIPKCS7_sign()\fR also applies to \fIPKCS7_verify()\fR.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
ERR_get_error(3), PKCS7_decrypt(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIPKCS7_decrypt()\fR was added to OpenSSL 0.9.5