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
|
=pod
=head1 NAME
EVP_KDF-SS - The Single Step / One Step EVP_KDF implementation
=head1 DESCRIPTION
The EVP_KDF-SS algorithm implements the Single Step key derivation function (SSKDF).
SSKDF derives a key using input such as a shared secret key (that was generated
during the execution of a key establishment scheme) and fixedinfo.
SSKDF is also informally referred to as 'Concat KDF'.
=head2 Auxiliary function
The implementation uses a selectable auxiliary function H, which can be one of:
=over 4
=item B<H(x) = hash(x, digest=md)>
=item B<H(x) = HMAC_hash(x, key=salt, digest=md)>
=item B<H(x) = KMACxxx(x, key=salt, custom="KDF", outlen=mac_size)>
=back
Both the HMAC and KMAC implementations set the key using the 'salt' value.
The hash and HMAC also require the digest to be set.
=head2 Identity
"SSKDF" is the name for this implementation; it
can be used with the EVP_KDF_fetch() function.
=head2 Supported parameters
The supported parameters are:
=over 4
=item "properties" (B<OSSL_KDF_PARAM_PROPERTIES>) <UTF8 string>
=item "digest" (B<OSSL_KDF_PARAM_DIGEST>) <UTF8 string>
=item "mac" (B<OSSL_KDF_PARAM_MAC>) <UTF8 string>
=item "maclen" (B<OSSL_KDF_PARAM_MAC_SIZE>) <unsigned integer>
=item "salt" (B<OSSL_KDF_PARAM_SALT>) <octet string>
These parameters work as described in L<EVP_KDF(3)/PARAMETERS>.
=item "key" (B<EVP_KDF_CTRL_SET_KEY>) <octet string>
This parameter set the shared secret that is used for key derivation.
=item "info" (B<OSSL_KDF_PARAM_INFO>) <octet string>
This parameter sets an optional value for fixedinfo, also known as otherinfo.
=back
=head1 NOTES
A context for SSKDF can be obtained by calling:
EVP_KDF *kdf = EVP_KDF_fetch(NULL, "SSKDF", NULL);
EVP_KDF_CTX *kctx = EVP_KDF_CTX_new(kdf);
The output length of an SSKDF is specified via the C<keylen>
parameter to the L<EVP_KDF-derive(3)> function.
=head1 EXAMPLES
This example derives 10 bytes using H(x) = SHA-256, with the secret key "secret"
and fixedinfo value "label":
EVP_KDF *kdf;
EVP_KDF_CTX *kctx;
unsigned char out[10];
OSSL_PARAM params[4], *p = params;
kdf = EVP_KDF_fetch(NULL, "SSKDF", NULL);
kctx = EVP_KDF_CTX_new(kdf);
EVP_KDF_free(kdf);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
SN_sha256, strlen(SN_sha256));
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
"secret", (size_t)6);
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
"label", (size_t)5);
*p = OSSL_PARAM_construct_end();
if (EVP_KDF_CTX_set_params(kctx, params) <= 0) {
error("EVP_KDF_CTX_set_params");
}
if (EVP_KDF_derive(kctx, out, sizeof(out)) <= 0) {
error("EVP_KDF_derive");
}
EVP_KDF_CTX_free(kctx);
This example derives 10 bytes using H(x) = HMAC(SHA-256), with the secret key "secret",
fixedinfo value "label" and salt "salt":
EVP_KDF *kdf;
EVP_KDF_CTX *kctx;
unsigned char out[10];
OSSL_PARAM params[6], *p = params;
kdf = EVP_KDF_fetch(NULL, "SSKDF", NULL);
kctx = EVP_KDF_CTX_new(kdf);
EVP_KDF_free(kdf);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_MAC,
SN_hmac, strlen(SN_hmac));
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
SN_sha256, strlen(SN_sha256));
*p++ = OSSL_PARAM_construct_octet_string(EVP_KDF_CTRL_SET_KEY,
"secret", (size_t)6);
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
"label", (size_t)5);
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
"salt", (size_t)4);
*p = OSSL_PARAM_construct_end();
if (EVP_KDF_CTX_set_params(kctx, params) <= 0) {
error("EVP_KDF_CTX_set_params");
}
if (EVP_KDF_derive(kctx, out, sizeof(out)) <= 0) {
error("EVP_KDF_derive");
}
EVP_KDF_CTX_free(kctx);
This example derives 10 bytes using H(x) = KMAC128(x,salt,outlen), with the secret key "secret"
fixedinfo value "label", salt of "salt" and KMAC outlen of 20:
EVP_KDF *kdf;
EVP_KDF_CTX *kctx;
unsigned char out[10];
OSSL_PARAM params[7], *p = params;
kdf = EVP_KDF_fetch(NULL, "SSKDF", NULL);
kctx = EVP_KDF_CTX_new(kdf);
EVP_KDF_free(kdf);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_MAC,
SN_kmac128, strlen(SN_kmac128));
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
SN_sha256, strlen(SN_sha256));
*p++ = OSSL_PARAM_construct_octet_string(EVP_KDF_CTRL_SET_KEY,
"secret", (size_t)6);
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
"label", (size_t)5);
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
"salt", (size_t)4);
*p++ = OSSL_PARAM_construct_size_t(OSSL_KDF_PARAM_MAC_SIZE, (size_t)20);
*p = OSSL_PARAM_construct_end();
if (EVP_KDF_CTX_set_params(kctx, params) <= 0) {
error("EVP_KDF_CTX_set_params");
}
if (EVP_KDF_derive(kctx, out, sizeof(out)) <= 0) {
error("EVP_KDF_derive");
}
EVP_KDF_CTX_free(kctx);
=head1 CONFORMING TO
NIST SP800-56Cr1.
=head1 SEE ALSO
L<EVP_KDF(3)>,
L<EVP_KDF_CTX_new(3)>,
L<EVP_KDF_CTX_free(3)>,
L<EVP_KDF_CTX_set_params(3)>,
L<EVP_KDF_size(3)>,
L<EVP_KDF_derive(3)>,
L<EVP_KDF(3)/PARAMETERS>
=head1 HISTORY
This functionality was added to OpenSSL 3.0.
=head1 COPYRIGHT
Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. Copyright
(c) 2019, Oracle and/or its affiliates. All rights reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut
|
