1=pod
2
3=head1 NAME
4
5EVP_RAND-TEST-RAND - The test EVP_RAND implementation
6
7=head1 DESCRIPTION
8
9Support for a test generator through the B<EVP_RAND> API. This generator is
10for test purposes only, it does not generate random numbers.
11
12=head2 Identity
13
14"TEST-RAND" is the name for this implementation; it can be used with the
15EVP_RAND_fetch() function.
16
17=head2 Supported parameters
18
19The supported parameters are:
20
21=over 4
22
23=item "state" (B<OSSL_RAND_PARAM_STATE>) <integer>
24
25These parameter works as described in L<EVP_RAND(3)/PARAMETERS>.
26
27=item "strength" (B<OSSL_RAND_PARAM_STRENGTH>) <unsigned integer>
28
29=item "reseed_requests" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer>
30
31=item "reseed_time_interval" (B<OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL>) <integer>
32
33=item "max_request" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer>
34
35=item "min_entropylen" (B<OSSL_DRBG_PARAM_MIN_ENTROPYLEN>) <unsigned integer>
36
37=item "max_entropylen" (B<OSSL_DRBG_PARAM_MAX_ENTROPYLEN>) <unsigned integer>
38
39=item "min_noncelen" (B<OSSL_DRBG_PARAM_MIN_NONCELEN>) <unsigned integer>
40
41=item "max_noncelen" (B<OSSL_DRBG_PARAM_MAX_NONCELEN>) <unsigned integer>
42
43=item "max_perslen" (B<OSSL_DRBG_PARAM_MAX_PERSLEN>) <unsigned integer>
44
45=item "max_adinlen" (B<OSSL_DRBG_PARAM_MAX_ADINLEN>) <unsigned integer>
46
47=item "reseed_counter" (B<OSSL_DRBG_PARAM_RESEED_COUNTER>) <unsigned integer>
48
49These parameters work as described in L<EVP_RAND(3)/PARAMETERS>, except that
50they can all be set as well as read.
51
52=item "test_entropy" (B<OSSL_RAND_PARAM_TEST_ENTROPY>) <octet string>
53
54Sets the bytes returned when the test generator is sent an entropy request.
55The current position is remembered across generate calls.
56If there are insufficient data present to satisfy a call, an error is returned.
57
58=item "test_nonce" (B<OSSL_RAND_PARAM_TEST_NONCE>) <octet string>
59
60Sets the bytes returned when the test generator is sent a nonce request.
61Each nonce request will return all of the bytes.
62
63=back
64
65=head1 NOTES
66
67A context for a test generator can be obtained by calling:
68
69 EVP_RAND *rand = EVP_RAND_fetch(NULL, "TEST-RAND", NULL);
70 EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand);
71
72=head1 EXAMPLES
73
74 EVP_RAND *rand;
75 EVP_RAND_CTX *rctx;
76 unsigned char bytes[100];
77 OSSL_PARAM params[4], *p = params;
78 unsigned char entropy[1000] = { ... };
79 unsigned char nonce[20] = { ... };
80 unsigned int strength = 48;
81
82 rand = EVP_RAND_fetch(NULL, "TEST-RAND", NULL);
83 rctx = EVP_RAND_CTX_new(rand, NULL);
84 EVP_RAND_free(rand);
85
86 *p++ = OSSL_PARAM_construct_uint(OSSL_RAND_PARAM_STRENGTH, &strength);
87 *p++ = OSSL_PARAM_construct_octet_string(OSSL_RAND_PARAM_TEST_ENTROPY,
88                                          entropy, sizeof(entropy));
89 *p++ = OSSL_PARAM_construct_octet_string(OSSL_RAND_PARAM_TEST_NONCE,
90                                          nonce, sizeof(nonce));
91 *p = OSSL_PARAM_construct_end();
92 EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params);
93
94 EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0);
95
96 EVP_RAND_CTX_free(rctx);
97
98=head1 SEE ALSO
99
100L<EVP_RAND(3)>,
101L<EVP_RAND(3)/PARAMETERS>
102
103=head1 HISTORY
104
105This functionality was added in OpenSSL 3.0.
106
107=head1 COPYRIGHT
108
109Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
110
111Licensed under the Apache License 2.0 (the "License").  You may not use
112this file except in compliance with the License.  You can obtain a copy
113in the file LICENSE in the source distribution or at
114L<https://www.openssl.org/source/license.html>.
115
116=cut
117