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=head1 NAME

CMS_digest_create_ex, CMS_digest_create
- Create CMS DigestedData object

=head1 SYNOPSIS

 #include <openssl/cms.h>

 CMS_ContentInfo *CMS_digest_create_ex(BIO *in, const EVP_MD *md,
                                       unsigned int flags, OSSL_LIB_CTX *ctx,
                                       const char *propq);

 CMS_ContentInfo *CMS_digest_create(BIO *in, const EVP_MD *md,
                                    unsigned int flags);

=head1 DESCRIPTION

CMS_digest_create_ex() creates a B<CMS_ContentInfo> structure
with a type B<NID_pkcs7_digest>. The data supplied via the I<in> BIO is digested
using I<md>. The library context I<libctx> and the property query I<propq> are
used when retrieving algorithms from providers.
The I<flags> field supports the B<CMS_DETACHED> and B<CMS_STREAM> flags,
Internally CMS_final() is called unless B<CMS_STREAM> is specified.

The B<CMS_ContentInfo> structure can be freed using L<CMS_ContentInfo_free(3)>.

CMS_digest_create() is similar to CMS_digest_create_ex()
but uses default values of NULL for the library context I<libctx> and the
property query I<propq>.


=head1 RETURN VALUES

If the allocation fails, CMS_digest_create_ex() and CMS_digest_create()
return NULL and set an error code that can be obtained by L<ERR_get_error(3)>.
Otherwise they return a pointer to the newly allocated structure.

=head1 SEE ALSO

L<ERR_get_error(3)>, L<CMS_final(3)>>

=head1 HISTORY

The CMS_digest_create_ex() method was added in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2020-2021 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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