1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
.\" $OpenBSD: evp.3,v 1.5 2018/04/18 01:12:11 schwarze Exp $
.\" OpenSSL a9c85cea Nov 11 09:33:55 2016 +0100
.\"
.\" This file was written by Ulf Moeller <ulf@openssl.org>,
.\" Matt Caswell <matt@openssl.org>, Geoff Thorpe <geoff@openssl.org>,
.\" and Dr. Stephen Henson <steve@openssl.org>.
.\" Copyright (c) 2000, 2002, 2006, 2013, 2016 The OpenSSL Project.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\" software must display the following acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\" endorse or promote products derived from this software without
.\" prior written permission. For written permission, please contact
.\" openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\" nor may "OpenSSL" appear in their names without prior written
.\" permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\" acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: April 18 2018 $
.Dt EVP 3
.Os
.Sh NAME
.Nm evp
.Nd high level cryptographic functions
.Sh SYNOPSIS
.In openssl/evp.h
.Sh DESCRIPTION
The EVP library provides a high level interface to cryptographic
functions.
.Pp
.Xr EVP_SealInit 3
and
.Xr EVP_OpenInit 3
provide public key encryption and decryption to implement digital
"envelopes".
.Pp
The
.Xr EVP_DigestSignInit 3
and
.Xr EVP_DigestVerifyInit 3
functions implement digital signatures and Message Authentication Codes
(MACs).
Also see the older
.Xr EVP_SignInit 3
and
.Xr EVP_VerifyInit 3
functions.
.Pp
Symmetric encryption is available with the
.Xr EVP_EncryptInit 3
functions.
The
.Xr EVP_DigestInit 3
functions provide message digests.
.Pp
Authenticated encryption with additional data (AEAD) is available with
the
.Xr EVP_AEAD_CTX_init 3
functions.
.Pp
The
.Fn EVP_PKEY_*
functions provide a high level interface to asymmetric algorithms.
To create a new
.Vt EVP_PKEY ,
see
.Xr EVP_PKEY_new 3 .
.Vt EVP_PKEY Ns s
can be associated with a private key of a particular algorithm
by using the functions described in the
.Xr EVP_PKEY_set1_RSA 3
page, or new keys can be generated using
.Xr EVP_PKEY_keygen 3 .
.Vt EVP_PKEY Ns s
can be compared using
.Xr EVP_PKEY_cmp 3
or printed using
.Xr EVP_PKEY_print_private 3 .
.Pp
The
.Fn EVP_PKEY_*
functions support the full range of asymmetric algorithm operations:
.Bl -bullet
.It
For key agreement, see
.Xr EVP_PKEY_derive 3 .
.It
For signing and verifying, see
.Xr EVP_PKEY_sign 3 ,
.Xr EVP_PKEY_verify 3 ,
and
.Xr EVP_PKEY_verify_recover 3 .
However, note that these functions do not perform a digest of the
data to be signed.
Therefore normally you would use the
.Xr EVP_DigestSignInit 3
functions for this purpose.
.It
For encryption and decryption see
.Xr EVP_PKEY_encrypt 3
and
.Xr EVP_PKEY_decrypt 3 ,
respectively.
However, note that these functions perform encryption and decryption only.
As public key encryption is an expensive operation, normally you
would wrap an encrypted message in a digital envelope using the
.Xr EVP_SealInit 3
and
.Xr EVP_OpenInit 3
functions.
.El
.Pp
The
.Xr EVP_BytesToKey 3
function provides some limited support for password based encryption.
Careful selection of the parameters will provide a PKCS#5 PBKDF1
compatible implementation.
However, new applications should typically not use this (preferring, for
example, PBKDF2 from PCKS#5).
.Pp
Algorithms are loaded with
.Xr OpenSSL_add_all_algorithms 3 .
.Pp
All the symmetric algorithms (ciphers), digests and asymmetric
algorithms (public key algorithms) can be replaced by
.Vt ENGINE
modules providing alternative implementations; see
.Xr ENGINE_register_RSA 3
and the related manual pages for more information.
If
.Vt ENGINE
implementations of ciphers or digests are registered as defaults,
then the various EVP functions will automatically use those
implementations in preference to built in software implementations.
.Pp
Although low level algorithm specific functions exist for many
algorithms, their use is discouraged.
They cannot be used with an
.Vt ENGINE ,
and
.Vt ENGINE
versions of new algorithms cannot be accessed using the low level
functions.
Using them also makes code harder to adapt to new algorithms, some
options are not cleanly supported at the low level, and some
operations are more efficient using the high level interfaces.
.Sh SEE ALSO
.Xr ENGINE_register_RSA 3 ,
.Xr EVP_AEAD_CTX_init 3 ,
.Xr EVP_BytesToKey 3 ,
.Xr EVP_DigestInit 3 ,
.Xr EVP_DigestSignInit 3 ,
.Xr EVP_EncryptInit 3 ,
.Xr EVP_OpenInit 3 ,
.Xr EVP_PKEY_decrypt 3 ,
.Xr EVP_PKEY_derive 3 ,
.Xr EVP_PKEY_encrypt 3 ,
.Xr EVP_PKEY_keygen 3 ,
.Xr EVP_PKEY_new 3 ,
.Xr EVP_PKEY_print_private 3 ,
.Xr EVP_PKEY_set1_RSA 3 ,
.Xr EVP_PKEY_sign 3 ,
.Xr EVP_PKEY_verify 3 ,
.Xr EVP_PKEY_verify_recover 3 ,
.Xr EVP_SealInit 3 ,
.Xr EVP_SignInit 3 ,
.Xr EVP_VerifyInit 3 ,
.Xr OpenSSL_add_all_algorithms 3
|
