flutter / third_party / openssl / 4b1b629725970384d6cf4dafe9e83e54859574cd / . / doc / man3 / DH_generate_parameters.pod

=pod | |

=head1 NAME | |

DH_generate_parameters_ex, DH_generate_parameters, | |

DH_check, DH_check_params, | |

DH_check_ex, DH_check_params_ex, DH_check_pub_key_ex | |

- generate and check Diffie-Hellman | |

parameters | |

=head1 SYNOPSIS | |

#include <openssl/dh.h> | |

The following functions have been deprecated since OpenSSL 3.0, and can be | |

hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, | |

see L<openssl_user_macros(7)>: | |

int DH_generate_parameters_ex(DH *dh, int prime_len, int generator, BN_GENCB *cb); | |

int DH_check(DH *dh, int *codes); | |

int DH_check_params(DH *dh, int *codes); | |

int DH_check_ex(const DH *dh); | |

int DH_check_params_ex(const DH *dh); | |

int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key); | |

The following functions have been deprecated since OpenSSL 0.9.8, and can be | |

hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, | |

see L<openssl_user_macros(7)>: | |

DH *DH_generate_parameters(int prime_len, int generator, | |

void (*callback)(int, int, void *), void *cb_arg); | |

=head1 DESCRIPTION | |

All of the functions described on this page are deprecated. | |

Applications should instead use L<EVP_PKEY_check(3)>, | |

L<EVP_PKEY_public_check(3)>, L<EVP_PKEY_private_check(3)> and | |

L<EVP_PKEY_param_check(3)>. | |

DH_generate_parameters_ex() generates Diffie-Hellman parameters that can | |

be shared among a group of users, and stores them in the provided B<DH> | |

structure. The pseudo-random number generator must be | |

seeded before calling it. | |

The parameters generated by DH_generate_parameters_ex() should not be used in | |

signature schemes. | |

B<prime_len> is the length in bits of the safe prime to be generated. | |

B<generator> is a small number E<gt> 1, typically 2 or 5. | |

A callback function may be used to provide feedback about the progress | |

of the key generation. If B<cb> is not B<NULL>, it will be | |

called as described in L<BN_generate_prime(3)> while a random prime | |

number is generated, and when a prime has been found, B<BN_GENCB_call(cb, 3, 0)> | |

is called. See L<BN_generate_prime_ex(3)> for information on | |

the BN_GENCB_call() function. | |

DH_generate_parameters() is similar to DH_generate_prime_ex() but | |

expects an old-style callback function; see | |

L<BN_generate_prime(3)> for information on the old-style callback. | |

DH_check_params() confirms that the B<p> and B<g> are likely enough to | |

be valid. | |

This is a lightweight check, if a more thorough check is needed, use | |

DH_check(). | |

The value of B<*codes> is updated with any problems found. | |

If B<*codes> is zero then no problems were found, otherwise the | |

following bits may be set: | |

=over 4 | |

=item DH_CHECK_P_NOT_PRIME | |

The parameter B<p> has been determined to not being an odd prime. | |

Note that the lack of this bit doesn't guarantee that B<p> is a | |

prime. | |

=item DH_NOT_SUITABLE_GENERATOR | |

The generator B<g> is not suitable. | |

Note that the lack of this bit doesn't guarantee that B<g> is | |

suitable, unless B<p> is known to be a strong prime. | |

=item DH_MODULUS_TOO_SMALL | |

The modulus is too small. | |

=item DH_MODULUS_TOO_LARGE | |

The modulus is too large. | |

=back | |

DH_check() confirms that the Diffie-Hellman parameters B<dh> are valid. The | |

value of B<*codes> is updated with any problems found. If B<*codes> is zero then | |

no problems were found, otherwise the following bits may be set: | |

=over 4 | |

=item DH_CHECK_P_NOT_PRIME | |

The parameter B<p> is not prime. | |

=item DH_CHECK_P_NOT_SAFE_PRIME | |

The parameter B<p> is not a safe prime and no B<q> value is present. | |

=item DH_UNABLE_TO_CHECK_GENERATOR | |

The generator B<g> cannot be checked for suitability. | |

=item DH_NOT_SUITABLE_GENERATOR | |

The generator B<g> is not suitable. | |

=item DH_CHECK_Q_NOT_PRIME | |

The parameter B<q> is not prime. | |

=item DH_CHECK_INVALID_Q_VALUE | |

The parameter B<q> is invalid. | |

=item DH_CHECK_INVALID_J_VALUE | |

The parameter B<j> is invalid. | |

=back | |

DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() are similar to | |

DH_check() and DH_check_params() respectively, but the error reasons are added | |

to the thread's error queue instead of provided as return values from the | |

function. | |

=head1 RETURN VALUES | |

DH_generate_parameters_ex(), DH_check() and DH_check_params() return 1 | |

if the check could be performed, 0 otherwise. | |

DH_generate_parameters() returns a pointer to the DH structure or NULL if | |

the parameter generation fails. | |

DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() return 1 if the | |

check is successful, 0 for failed. | |

The error codes can be obtained by L<ERR_get_error(3)>. | |

=head1 SEE ALSO | |

L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, | |

L<DH_free(3)> | |

=head1 HISTORY | |

All of these functions were deprecated in OpenSSL 3.0. | |

DH_generate_parameters() was deprecated in OpenSSL 0.9.8; use | |

DH_generate_parameters_ex() instead. | |

=head1 COPYRIGHT | |

Copyright 2000-2020 The OpenSSL Project Authors. 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>. | |

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