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Diffstat (limited to 'doc/man3/DH_set_method.pod')
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diff --git a/doc/man3/DH_set_method.pod b/doc/man3/DH_set_method.pod new file mode 100644 index 000000000000..ea45961f1500 --- /dev/null +++ b/doc/man3/DH_set_method.pod @@ -0,0 +1,88 @@ +=pod + +=head1 NAME + +DH_set_default_method, DH_get_default_method, +DH_set_method, DH_new_method, DH_OpenSSL - select DH method + +=head1 SYNOPSIS + + #include <openssl/dh.h> + + void DH_set_default_method(const DH_METHOD *meth); + + const DH_METHOD *DH_get_default_method(void); + + int DH_set_method(DH *dh, const DH_METHOD *meth); + + DH *DH_new_method(ENGINE *engine); + + const DH_METHOD *DH_OpenSSL(void); + +=head1 DESCRIPTION + +A B<DH_METHOD> specifies the functions that OpenSSL uses for Diffie-Hellman +operations. By modifying the method, alternative implementations +such as hardware accelerators may be used. IMPORTANT: See the NOTES section for +important information about how these DH API functions are affected by the use +of B<ENGINE> API calls. + +Initially, the default DH_METHOD is the OpenSSL internal implementation, as +returned by DH_OpenSSL(). + +DH_set_default_method() makes B<meth> the default method for all DH +structures created later. +B<NB>: This is true only whilst no ENGINE has been set +as a default for DH, so this function is no longer recommended. +This function is not thread-safe and should not be called at the same time +as other OpenSSL functions. + +DH_get_default_method() returns a pointer to the current default DH_METHOD. +However, the meaningfulness of this result is dependent on whether the ENGINE +API is being used, so this function is no longer recommended. + +DH_set_method() selects B<meth> to perform all operations using the key B<dh>. +This will replace the DH_METHOD used by the DH key and if the previous method +was supplied by an ENGINE, the handle to that ENGINE will be released during the +change. It is possible to have DH keys that only work with certain DH_METHOD +implementations (eg. from an ENGINE module that supports embedded +hardware-protected keys), and in such cases attempting to change the DH_METHOD +for the key can have unexpected results. + +DH_new_method() allocates and initializes a DH structure so that B<engine> will +be used for the DH operations. If B<engine> is NULL, the default ENGINE for DH +operations is used, and if no default ENGINE is set, the DH_METHOD controlled by +DH_set_default_method() is used. + +A new DH_METHOD object may be constructed using DH_meth_new() (see +L<DH_meth_new(3)>). + +=head1 RETURN VALUES + +DH_OpenSSL() and DH_get_default_method() return pointers to the respective +B<DH_METHOD>s. + +DH_set_default_method() returns no value. + +DH_set_method() returns non-zero if the provided B<meth> was successfully set as +the method for B<dh> (including unloading the ENGINE handle if the previous +method was supplied by an ENGINE). + +DH_new_method() returns NULL and sets an error code that can be obtained by +L<ERR_get_error(3)> if the allocation fails. Otherwise it +returns a pointer to the newly allocated structure. + +=head1 SEE ALSO + +L<DH_new(3)>, L<DH_new(3)>, L<DH_meth_new(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 |