1RSA_GENERATE_KEY(3ossl)             OpenSSL            RSA_GENERATE_KEY(3ossl)
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NAME

6       EVP_RSA_gen, RSA_generate_key_ex, RSA_generate_key,
7       RSA_generate_multi_prime_key - generate RSA key pair
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SYNOPSIS

10        #include <openssl/rsa.h>
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12        EVP_PKEY *EVP_RSA_gen(unsigned int bits);
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14       The following functions have been deprecated since OpenSSL 3.0, and can
15       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
16       version value, see openssl_user_macros(7):
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18        int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb);
19        int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes, BIGNUM *e, BN_GENCB *cb);
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21       The following function has been deprecated since OpenSSL 0.9.8, and can
22       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
23       version value, see openssl_user_macros(7):
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25        RSA *RSA_generate_key(int bits, unsigned long e,
26                              void (*callback)(int, int, void *), void *cb_arg);
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DESCRIPTION

29       EVP_RSA_gen() generates a new RSA key pair with modulus size bits.
30
31       All of the functions described below are deprecated.  Applications
32       should instead use EVP_RSA_gen(), EVP_PKEY_Q_keygen(3), or
33       EVP_PKEY_keygen_init(3) and EVP_PKEY_keygen(3).
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35       RSA_generate_key_ex() generates a 2-prime RSA key pair and stores it in
36       the RSA structure provided in rsa.
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38       RSA_generate_multi_prime_key() generates a multi-prime RSA key pair and
39       stores it in the RSA structure provided in rsa. The number of primes is
40       given by the primes parameter.  If the automatic seeding or reseeding
41       of the OpenSSL CSPRNG fails due to external circumstances (see
42       RAND(7)), the operation will fail.
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44       The modulus size will be of length bits, the number of primes to form
45       the modulus will be primes, and the public exponent will be e. Key
46       sizes with num < 1024 should be considered insecure. The exponent is an
47       odd number, typically 3, 17 or 65537.
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49       In order to maintain adequate security level, the maximum number of
50       permitted primes depends on modulus bit length:
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52          <1024 | >=1024 | >=4096 | >=8192
53          ------+--------+--------+-------
54            2   |   3    |   4    |   5
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56       A callback function may be used to provide feedback about the progress
57       of the key generation. If cb is not NULL, it will be called as follows
58       using the BN_GENCB_call() function described on the
59       BN_generate_prime(3) page.
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61       RSA_generate_key() is similar to RSA_generate_key_ex() but expects an
62       old-style callback function; see BN_generate_prime(3) for information
63       on the old-style callback.
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65       • While a random prime number is generated, it is called as described
66         in BN_generate_prime(3).
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68       • When the n-th randomly generated prime is rejected as not suitable
69         for the key, BN_GENCB_call(cb, 2, n) is called.
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71       • When a random p has been found with p-1 relatively prime to e, it is
72         called as BN_GENCB_call(cb, 3, 0).
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74       The process is then repeated for prime q and other primes (if any) with
75       BN_GENCB_call(cb, 3, i) where i indicates the i-th prime.
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RETURN VALUES

78       EVP_RSA_gen() returns an EVP_PKEY or NULL on failure.
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80       RSA_generate_multi_prime_key() returns 1 on success or 0 on error.
81       RSA_generate_key_ex() returns 1 on success or 0 on error.  The error
82       codes can be obtained by ERR_get_error(3).
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84       RSA_generate_key() returns a pointer to the RSA structure or NULL if
85       the key generation fails.
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BUGS

88       BN_GENCB_call(cb, 2, x) is used with two different meanings.
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SEE ALSO

91       EVP_PKEY_Q_keygen(3) BN_generate_prime(3), ERR_get_error(3),
92       RAND_bytes(3), RAND(7)
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HISTORY

95       EVP_RSA_gen() was added in OpenSSL 3.0.  All other functions described
96       here were deprecated in OpenSSL 3.0.  For replacement see
97       EVP_PKEY-RSA(7).
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100       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
101
102       Licensed under the Apache License 2.0 (the "License").  You may not use
103       this file except in compliance with the License.  You can obtain a copy
104       in the file LICENSE in the source distribution or at
105       <https://www.openssl.org/source/license.html>.
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1093.1.1                             2023-08-31           RSA_GENERATE_KEY(3ossl)
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