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author | Wojtek Kosior <wk@koszkonutek-tmp.pl.eu.org> | 2021-04-30 00:33:56 +0200 |
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committer | Wojtek Kosior <wk@koszkonutek-tmp.pl.eu.org> | 2021-04-30 00:33:56 +0200 |
commit | aa4d426b4d3527d7e166df1a05058c9a4a0f6683 (patch) | |
tree | 4ff17ce8b89a2321b9d0ed4bcfc37c447bcb6820 /openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod | |
download | smtps-and-pop3s-console-program-master.tar.gz smtps-and-pop3s-console-program-master.zip |
Diffstat (limited to 'openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod')
-rw-r--r-- | openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod b/openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod new file mode 100644 index 0000000..ce178af --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/DH_generate_parameters.pod @@ -0,0 +1,134 @@ +=pod + +=head1 NAME + +DH_generate_parameters_ex, DH_generate_parameters, +DH_check, DH_check_params - generate and check Diffie-Hellman +parameters + +=head1 SYNOPSIS + + #include <openssl/dh.h> + + 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); + +Deprecated: + + #if OPENSSL_API_COMPAT < 0x00908000L + DH *DH_generate_parameters(int prime_len, int generator, + void (*callback)(int, int, void *), void *cb_arg); + #endif + +=head1 DESCRIPTION + +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 prior to calling DH_generate_parameters(). + +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(3)> for information on +the BN_GENCB_call() function. + +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. + +=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 + +=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() (deprecated) returns a pointer to the DH structure, or +NULL if the parameter generation fails. + +The error codes can be obtained by L<ERR_get_error(3)>. + +=head1 NOTES + +DH_generate_parameters_ex() and DH_generate_parameters() may run for several +hours before finding a suitable prime. + +The parameters generated by DH_generate_parameters_ex() and DH_generate_parameters() +are not to be used in signature schemes. + +=head1 SEE ALSO + +L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, +L<DH_free(3)> + +=head1 COPYRIGHT + +Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (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>. + +=cut |