1EVP_RAND-CTR-DRBG(7ossl)            OpenSSL           EVP_RAND-CTR-DRBG(7ossl)
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NAME

6       EVP_RAND-CTR-DRBG - The CTR DRBG EVP_RAND implementation
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DESCRIPTION

9       Support for the counter deterministic random bit generator through the
10       EVP_RAND API.
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12   Identity
13       "CTR-DRBG" is the name for this implementation; it can be used with the
14       EVP_RAND_fetch() function.
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16   Supported parameters
17       The supported parameters are:
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19       "state" (OSSL_RAND_PARAM_STATE) <integer>
20       "strength" (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>
21       "max_request" (OSSL_RAND_PARAM_MAX_REQUEST) <unsigned integer>
22       "reseed_requests" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
23       "reseed_time_interval" (OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL) <integer>
24       "min_entropylen" (OSSL_DRBG_PARAM_MIN_ENTROPYLEN) <unsigned integer>
25       "max_entropylen" (OSSL_DRBG_PARAM_MAX_ENTROPYLEN) <unsigned integer>
26       "min_noncelen" (OSSL_DRBG_PARAM_MIN_NONCELEN) <unsigned integer>
27       "max_noncelen" (OSSL_DRBG_PARAM_MAX_NONCELEN) <unsigned integer>
28       "max_perslen" (OSSL_DRBG_PARAM_MAX_PERSLEN) <unsigned integer>
29       "max_adinlen" (OSSL_DRBG_PARAM_MAX_ADINLEN) <unsigned integer>
30       "reseed_counter" (OSSL_DRBG_PARAM_RESEED_COUNTER) <unsigned integer>
31       "properties" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>
32       "cipher" (OSSL_DRBG_PARAM_CIPHER) <UTF8 string>
33           These parameters work as described in "PARAMETERS" in EVP_RAND(3).
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35       "use_derivation_function" (OSSL_DRBG_PARAM_USE_DF) <integer>
36           This Boolean indicates if a derivation function should be used or
37           not.  A nonzero value (the default) uses the derivation function.
38           A zero value does not.
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NOTES

41       A context for CTR DRBG can be obtained by calling:
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43        EVP_RAND *rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL);
44        EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand);
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EXAMPLES

47        EVP_RAND *rand;
48        EVP_RAND_CTX *rctx;
49        unsigned char bytes[100];
50        OSSL_PARAM params[2], *p = params;
51        unsigned int strength = 128;
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53        rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL);
54        rctx = EVP_RAND_CTX_new(rand, NULL);
55        EVP_RAND_free(rand);
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57        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER,
58                                                SN_aes_256_ctr, 0);
59        *p = OSSL_PARAM_construct_end();
60        EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params);
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62        EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0);
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64        EVP_RAND_CTX_free(rctx);
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CONFORMING TO

67       NIST SP 800-90A and SP 800-90B
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SEE ALSO

70       EVP_RAND(3), "PARAMETERS" in EVP_RAND(3)
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73       Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
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75       Licensed under the Apache License 2.0 (the "License").  You may not use
76       this file except in compliance with the License.  You can obtain a copy
77       in the file LICENSE in the source distribution or at
78       <https://www.openssl.org/source/license.html>.
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823.0.5                             2022-07-05          EVP_RAND-CTR-DRBG(7ossl)
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