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=head1 NAME

EVP_set_default_properties, EVP_default_properties_enable_fips,
EVP_default_properties_is_fips_enabled, EVP_get1_default_properties
- manage default properties for future algorithm fetches

=head1 SYNOPSIS

 #include <openssl/evp.h>

 int EVP_set_default_properties(OSSL_LIB_CTX *libctx, const char *propq);
 char *EVP_get1_default_properties(OSSL_LIB_CTX *libctx);
 int EVP_default_properties_enable_fips(OSSL_LIB_CTX *libctx, int enable);
 int EVP_default_properties_is_fips_enabled(OSSL_LIB_CTX *libctx);

=head1 DESCRIPTION

EVP_set_default_properties() sets the default properties for all
future EVP algorithm fetches, implicit as well as explicit. See
L<crypto(7)/ALGORITHM FETCHING> for information about implicit and explicit
fetching.

EVP_set_default_properties stores the properties given with the string
I<propq> among the EVP data that's been stored in the library context
given with I<libctx> (NULL signifies the default library context).

Any previous default property for the specified library context will
be dropped.

EVP_get1_default_properties() gets the default properties set for all future EVP
algorithm fetches, implicit as well as explicit, for the specific library
context.

EVP_default_properties_enable_fips() sets the 'fips=yes' to be a default property
if I<enable> is non zero, otherwise it clears 'fips' from the default property
query for the given I<libctx>. It merges the fips default property query with any
existing query strings that have been set via EVP_set_default_properties().

EVP_default_properties_is_fips_enabled() indicates if 'fips=yes' is a default
property for the given I<libctx>.

=head1 NOTES

EVP_set_default_properties() and  EVP_default_properties_enable_fips() are not
thread safe. They are intended to be called only during the initialisation
phase of a I<libctx>.

EVP_get1_default_properties() is not thread safe. The application must ensure
that the context reference is valid and default fetching properties are not
being modified by a different thread.

=head1 RETURN VALUES

EVP_set_default_properties() and  EVP_default_properties_enable_fips() return 1
on success, or 0 on failure. An error is placed on the error stack if a
failure occurs.

EVP_default_properties_is_fips_enabled() returns 1 if the 'fips=yes' default
property is set for the given I<libctx>, otherwise it returns 0.

EVP_get1_default_properties() returns allocated memory that must be freed by
L<OPENSSL_free(3)> on success and NULL on failure.

=head1 SEE ALSO

L<EVP_MD_fetch(3)>

=head1 HISTORY

The functions EVP_set_default_properties(), EVP_default_properties_enable_fips(),
EVP_default_properties_is_fips_enabled() were added in OpenSSL 3.0.

The function EVP_get1_default_properties() was added in OpenSSL 3.5.


=head1 COPYRIGHT

Copyright 2019-2021 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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