1DSA_GENERATE_PARAMETERS(3ossl)      OpenSSL     DSA_GENERATE_PARAMETERS(3ossl)
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NAME

6       DSA_generate_parameters_ex, DSA_generate_parameters - generate DSA
7       parameters
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SYNOPSIS

10        #include <openssl/dsa.h>
11
12       The following functions have been deprecated since OpenSSL 3.0, and can
13       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
14       version value, see openssl_user_macros(7):
15
16        int DSA_generate_parameters_ex(DSA *dsa, int bits,
17                                       const unsigned char *seed, int seed_len,
18                                       int *counter_ret, unsigned long *h_ret,
19                                       BN_GENCB *cb);
20
21       The following functions have been deprecated since OpenSSL 0.9.8, and
22       can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
23       version value, see openssl_user_macros(7):
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25        DSA *DSA_generate_parameters(int bits, unsigned char *seed, int seed_len,
26                                     int *counter_ret, unsigned long *h_ret,
27                                     void (*callback)(int, int, void *), void *cb_arg);
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DESCRIPTION

30       All of the functions described on this page are deprecated.
31       Applications should instead use EVP_PKEY_paramgen_init(3) and
32       EVP_PKEY_keygen(3) as described in EVP_PKEY-DSA(7).
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34       DSA_generate_parameters_ex() generates primes p and q and a generator g
35       for use in the DSA and stores the result in dsa.
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37       bits is the length of the prime p to be generated.  For lengths under
38       2048 bits, the length of q is 160 bits; for lengths greater than or
39       equal to 2048 bits, the length of q is set to 256 bits.
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41       If seed is NULL, the primes will be generated at random.  If seed_len
42       is less than the length of q, an error is returned.
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44       DSA_generate_parameters_ex() places the iteration count in *counter_ret
45       and a counter used for finding a generator in *h_ret, unless these are
46       NULL.
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48       A callback function may be used to provide feedback about the progress
49       of the key generation. If cb is not NULL, it will be called as shown
50       below. For information on the BN_GENCB structure and the BN_GENCB_call
51       function discussed below, refer to BN_generate_prime(3).
52
53       DSA_generate_prime() is similar to DSA_generate_prime_ex() but expects
54       an old-style callback function; see BN_generate_prime(3) for
55       information on the old-style callback.
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57       • When a candidate for q is generated, BN_GENCB_call(cb, 0, m++) is
58         called (m is 0 for the first candidate).
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60       • When a candidate for q has passed a test by trial division,
61         BN_GENCB_call(cb, 1, -1) is called.  While a candidate for q is
62         tested by Miller-Rabin primality tests, BN_GENCB_call(cb, 1, i) is
63         called in the outer loop (once for each witness that confirms that
64         the candidate may be prime); i is the loop counter (starting at 0).
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66       • When a prime q has been found, BN_GENCB_call(cb, 2, 0) and
67         BN_GENCB_call(cb, 3, 0) are called.
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69       • Before a candidate for p (other than the first) is generated and
70         tested, BN_GENCB_call(cb, 0, counter) is called.
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72       • When a candidate for p has passed the test by trial division,
73         BN_GENCB_call(cb, 1, -1) is called.  While it is tested by the
74         Miller-Rabin primality test, BN_GENCB_call(cb, 1, i) is called in the
75         outer loop (once for each witness that confirms that the candidate
76         may be prime).  i is the loop counter (starting at 0).
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78       • When p has been found, BN_GENCB_call(cb, 2, 1) is called.
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80       • When the generator has been found, BN_GENCB_call(cb, 3, 1) is called.
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RETURN VALUES

83       DSA_generate_parameters_ex() returns a 1 on success, or 0 otherwise.
84       The error codes can be obtained by ERR_get_error(3).
85
86       DSA_generate_parameters() returns a pointer to the DSA structure or
87       NULL if the parameter generation fails.
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BUGS

90       Seed lengths greater than 20 are not supported.
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SEE ALSO

93       DSA_new(3), ERR_get_error(3), RAND_bytes(3), DSA_free(3),
94       BN_generate_prime(3)
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HISTORY

97       DSA_generate_parameters_ex() was deprecated in OpenSSL 3.0.
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99       DSA_generate_parameters() was deprecated in OpenSSL 0.9.8; use
100       DSA_generate_parameters_ex() instead.
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103       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
104
105       Licensed under the Apache License 2.0 (the "License").  You may not use
106       this file except in compliance with the License.  You can obtain a copy
107       in the file LICENSE in the source distribution or at
108       <https://www.openssl.org/source/license.html>.
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1123.0.9                             2023-07-27    DSA_GENERATE_PARAMETERS(3ossl)
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