216 lines
6.8 KiB
Groff
216 lines
6.8 KiB
Groff
.\" $NetBSD: EVP_SealInit.3,v 1.6 2002/02/07 07:00:39 ross Exp $
|
|
.\"
|
|
.\" Automatically generated by Pod::Man version 1.02
|
|
.\" Thu Apr 12 19:27:01 2001
|
|
.\"
|
|
.\" 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 "EVP_SealInit 3"
|
|
.TH EVP_SealInit 3 "0.9.6a" "2001-04-12" "OpenSSL"
|
|
.UC
|
|
.SH "NAME"
|
|
EVP_SealInit, EVP_SealUpdate, EVP_SealFinal \- \s-1EVP\s0 envelope encryption
|
|
.SH "LIBRARY"
|
|
libcrypto, -lcrypto
|
|
.SH "SYNOPSIS"
|
|
.IX Header "SYNOPSIS"
|
|
.Vb 1
|
|
\& #include \*[Lt]openssl/evp.h\*[Gt]
|
|
.Ve
|
|
.Vb 6
|
|
\& int EVP_SealInit(EVP_CIPHER_CTX *ctx, EVP_CIPHER *type, unsigned char **ek,
|
|
\& int *ekl, unsigned char *iv,EVP_PKEY **pubk, int npubk);
|
|
\& int EVP_SealUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
|
|
\& int *outl, unsigned char *in, int inl);
|
|
\& int EVP_SealFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
|
|
\& int *outl);
|
|
.Ve
|
|
.SH "DESCRIPTION"
|
|
.IX Header "DESCRIPTION"
|
|
The \s-1EVP\s0 envelope routines are a high level interface to envelope
|
|
encryption. They generate a random key and then \*(L"envelope\*(R" it by
|
|
using public key encryption. Data can then be encrypted using this
|
|
key.
|
|
.PP
|
|
\&\fIEVP_SealInit()\fR initializes a cipher context \fBctx\fR for encryption
|
|
with cipher \fBtype\fR using a random secret key and \s-1IV\s0 supplied in
|
|
the \fBiv\fR parameter. \fBtype\fR is normally supplied by a function such
|
|
as \fIEVP_des_cbc()\fR. The secret key is encrypted using one or more public
|
|
keys, this allows the same encrypted data to be decrypted using any
|
|
of the corresponding private keys. \fBek\fR is an array of buffers where
|
|
the public key encrypted secret key will be written, each buffer must
|
|
contain enough room for the corresponding encrypted key: that is
|
|
\&\fBek[i]\fR must have room for \fBEVP_PKEY_size(pubk[i])\fR bytes. The actual
|
|
size of each encrypted secret key is written to the array \fBekl\fR. \fBpubk\fR is
|
|
an array of \fBnpubk\fR public keys.
|
|
.PP
|
|
\&\fIEVP_SealUpdate()\fR and \fIEVP_SealFinal()\fR have exactly the same properties
|
|
as the \fIEVP_EncryptUpdate()\fR and \fIEVP_EncryptFinal()\fR routines, as
|
|
documented on the EVP_EncryptInit(3) manual
|
|
page.
|
|
.SH "RETURN VALUES"
|
|
.IX Header "RETURN VALUES"
|
|
\&\fIEVP_SealInit()\fR returns 0 on error or \fBnpubk\fR if successful.
|
|
.PP
|
|
\&\fIEVP_SealUpdate()\fR and \fIEVP_SealFinal()\fR return 1 for success and 0 for
|
|
failure.
|
|
.SH "NOTES"
|
|
.IX Header "NOTES"
|
|
Because a random secret key is generated the random number generator
|
|
must be seeded before calling \fIEVP_SealInit()\fR.
|
|
.PP
|
|
The public key must be \s-1RSA\s0 because it is the only OpenSSL public key
|
|
algorithm that supports key transport.
|
|
.PP
|
|
Envelope encryption is the usual method of using public key encryption
|
|
on large amounts of data, this is because public key encryption is slow
|
|
but symmetric encryption is fast. So symmetric encryption is used for
|
|
bulk encryption and the small random symmetric key used is transferred
|
|
using public key encryption.
|
|
.PP
|
|
It is possible to call \fIEVP_SealInit()\fR twice in the same way as
|
|
\&\fIEVP_EncryptInit()\fR. The first call should have \fBnpubk\fR set to 0
|
|
and (after setting any cipher parameters) it should be called again
|
|
with \fBtype\fR set to \s-1NULL\s0.
|
|
.SH "SEE ALSO"
|
|
.IX Header "SEE ALSO"
|
|
openssl_evp(3), openssl_rand(3),
|
|
EVP_EncryptInit(3),
|
|
EVP_OpenInit(3)
|
|
.SH "HISTORY"
|
|
.IX Header "HISTORY"
|