Update files for OpenSSL-1.0.0f import.
[dragonfly.git] / secure / lib / libcrypto / man / EVP_SealInit.3
CommitLineData
e3261593 1.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.19)
8b0cefbb
JR
2.\"
3.\" Standard preamble:
4.\" ========================================================================
8b0cefbb 5.de Sp \" Vertical space (when we can't use .PP)
984263bc
MD
6.if t .sp .5v
7.if n .sp
8..
8b0cefbb 9.de Vb \" Begin verbatim text
984263bc
MD
10.ft CW
11.nf
12.ne \\$1
13..
8b0cefbb 14.de Ve \" End verbatim text
984263bc 15.ft R
984263bc
MD
16.fi
17..
8b0cefbb
JR
18.\" Set up some character translations and predefined strings. \*(-- will
19.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
e257b235
PA
20.\" double quote, and \*(R" will give a right double quote. \*(C+ will
21.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
22.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
23.\" nothing in troff, for use with C<>.
24.tr \(*W-
8b0cefbb 25.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
984263bc 26.ie n \{\
8b0cefbb
JR
27. ds -- \(*W-
28. ds PI pi
29. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
30. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
31. ds L" ""
32. ds R" ""
33. ds C` ""
34. ds C' ""
984263bc
MD
35'br\}
36.el\{\
8b0cefbb
JR
37. ds -- \|\(em\|
38. ds PI \(*p
39. ds L" ``
40. ds R" ''
984263bc 41'br\}
8b0cefbb 42.\"
e257b235
PA
43.\" Escape single quotes in literal strings from groff's Unicode transform.
44.ie \n(.g .ds Aq \(aq
45.el .ds Aq '
46.\"
8b0cefbb 47.\" If the F register is turned on, we'll generate index entries on stderr for
01185282 48.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
8b0cefbb
JR
49.\" entries marked with X<> in POD. Of course, you'll have to process the
50.\" output yourself in some meaningful fashion.
e257b235 51.ie \nF \{\
8b0cefbb
JR
52. de IX
53. tm Index:\\$1\t\\n%\t"\\$2"
984263bc 54..
8b0cefbb
JR
55. nr % 0
56. rr F
984263bc 57.\}
e257b235
PA
58.el \{\
59. de IX
60..
61.\}
aac4ff6f 62.\"
8b0cefbb
JR
63.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
64.\" Fear. Run. Save yourself. No user-serviceable parts.
65. \" fudge factors for nroff and troff
984263bc 66.if n \{\
8b0cefbb
JR
67. ds #H 0
68. ds #V .8m
69. ds #F .3m
70. ds #[ \f1
71. ds #] \fP
984263bc
MD
72.\}
73.if t \{\
8b0cefbb
JR
74. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
75. ds #V .6m
76. ds #F 0
77. ds #[ \&
78. ds #] \&
984263bc 79.\}
8b0cefbb 80. \" simple accents for nroff and troff
984263bc 81.if n \{\
8b0cefbb
JR
82. ds ' \&
83. ds ` \&
84. ds ^ \&
85. ds , \&
86. ds ~ ~
87. ds /
984263bc
MD
88.\}
89.if t \{\
8b0cefbb
JR
90. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
91. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
92. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
93. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
94. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
95. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
984263bc 96.\}
8b0cefbb 97. \" troff and (daisy-wheel) nroff accents
984263bc
MD
98.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
99.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
100.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
101.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
102.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
103.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
104.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
105.ds ae a\h'-(\w'a'u*4/10)'e
106.ds Ae A\h'-(\w'A'u*4/10)'E
8b0cefbb 107. \" corrections for vroff
984263bc
MD
108.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
109.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
8b0cefbb 110. \" for low resolution devices (crt and lpr)
984263bc
MD
111.if \n(.H>23 .if \n(.V>19 \
112\{\
8b0cefbb
JR
113. ds : e
114. ds 8 ss
115. ds o a
116. ds d- d\h'-1'\(ga
117. ds D- D\h'-1'\(hy
118. ds th \o'bp'
119. ds Th \o'LP'
120. ds ae ae
121. ds Ae AE
984263bc
MD
122.\}
123.rm #[ #] #H #V #F C
8b0cefbb
JR
124.\" ========================================================================
125.\"
126.IX Title "EVP_SealInit 3"
e3261593 127.TH EVP_SealInit 3 "2012-01-04" "1.0.0f" "OpenSSL"
e257b235
PA
128.\" For nroff, turn off justification. Always turn off hyphenation; it makes
129.\" way too many mistakes in technical documents.
130.if n .ad l
131.nh
984263bc 132.SH "NAME"
74dab6c2 133EVP_SealInit, EVP_SealUpdate, EVP_SealFinal \- EVP envelope encryption
984263bc 134.SH "SYNOPSIS"
8b0cefbb 135.IX Header "SYNOPSIS"
984263bc
MD
136.Vb 1
137\& #include <openssl/evp.h>
e257b235 138\&
a561f9ff
SS
139\& int EVP_SealInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
140\& unsigned char **ek, int *ekl, unsigned char *iv,
141\& EVP_PKEY **pubk, int npubk);
984263bc
MD
142\& int EVP_SealUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
143\& int *outl, unsigned char *in, int inl);
144\& int EVP_SealFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
145\& int *outl);
146.Ve
147.SH "DESCRIPTION"
8b0cefbb
JR
148.IX Header "DESCRIPTION"
149The \s-1EVP\s0 envelope routines are a high level interface to envelope
150encryption. They generate a random key and \s-1IV\s0 (if required) then
151\&\*(L"envelope\*(R" it by using public key encryption. Data can then be
984263bc
MD
152encrypted using this key.
153.PP
8b0cefbb
JR
154\&\fIEVP_SealInit()\fR initializes a cipher context \fBctx\fR for encryption
155with cipher \fBtype\fR using a random secret key and \s-1IV\s0. \fBtype\fR is normally
984263bc
MD
156supplied by a function such as \fIEVP_des_cbc()\fR. The secret key is encrypted
157using one or more public keys, this allows the same encrypted data to be
158decrypted using any of the corresponding private keys. \fBek\fR is an array of
159buffers where the public key encrypted secret key will be written, each buffer
160must contain enough room for the corresponding encrypted key: that is
8b0cefbb 161\&\fBek[i]\fR must have room for \fBEVP_PKEY_size(pubk[i])\fR bytes. The actual
984263bc
MD
162size of each encrypted secret key is written to the array \fBekl\fR. \fBpubk\fR is
163an array of \fBnpubk\fR public keys.
164.PP
8b0cefbb
JR
165The \fBiv\fR parameter is a buffer where the generated \s-1IV\s0 is written to. It must
166contain enough room for the corresponding cipher's \s-1IV\s0, as determined by (for
167example) EVP_CIPHER_iv_length(type).
984263bc 168.PP
8b0cefbb
JR
169If the cipher does not require an \s-1IV\s0 then the \fBiv\fR parameter is ignored
170and can be \fB\s-1NULL\s0\fR.
984263bc 171.PP
8b0cefbb 172\&\fIEVP_SealUpdate()\fR and \fIEVP_SealFinal()\fR have exactly the same properties
984263bc 173as the \fIEVP_EncryptUpdate()\fR and \fIEVP_EncryptFinal()\fR routines, as
8b0cefbb 174documented on the \fIEVP_EncryptInit\fR\|(3) manual
e257b235 175page.
984263bc 176.SH "RETURN VALUES"
8b0cefbb
JR
177.IX Header "RETURN VALUES"
178\&\fIEVP_SealInit()\fR returns 0 on error or \fBnpubk\fR if successful.
984263bc 179.PP
8b0cefbb 180\&\fIEVP_SealUpdate()\fR and \fIEVP_SealFinal()\fR return 1 for success and 0 for
984263bc
MD
181failure.
182.SH "NOTES"
8b0cefbb 183.IX Header "NOTES"
984263bc
MD
184Because a random secret key is generated the random number generator
185must be seeded before calling \fIEVP_SealInit()\fR.
186.PP
8b0cefbb 187The public key must be \s-1RSA\s0 because it is the only OpenSSL public key
984263bc
MD
188algorithm that supports key transport.
189.PP
190Envelope encryption is the usual method of using public key encryption
191on large amounts of data, this is because public key encryption is slow
192but symmetric encryption is fast. So symmetric encryption is used for
193bulk encryption and the small random symmetric key used is transferred
194using public key encryption.
195.PP
196It is possible to call \fIEVP_SealInit()\fR twice in the same way as
8b0cefbb 197\&\fIEVP_EncryptInit()\fR. The first call should have \fBnpubk\fR set to 0
984263bc 198and (after setting any cipher parameters) it should be called again
8b0cefbb 199with \fBtype\fR set to \s-1NULL\s0.
984263bc 200.SH "SEE ALSO"
74dab6c2 201.IX Header "SEE ALSO"
8b0cefbb
JR
202\&\fIevp\fR\|(3), \fIrand\fR\|(3),
203\&\fIEVP_EncryptInit\fR\|(3),
204\&\fIEVP_OpenInit\fR\|(3)
205.SH "HISTORY"
984263bc 206.IX Header "HISTORY"
8b0cefbb 207\&\fIEVP_SealFinal()\fR did not return a value before OpenSSL 0.9.7.