=pod

=begin comment

This is a recommended way to describe OSSL_STORE loaders,
"ossl_store-{name}", where {name} is replaced with the name of the
scheme it implements, in man section 7.

=end comment

=head1 NAME

ossl_store-file - The store 'file' scheme loader

=head1 SYNOPSIS

=for openssl generic

#include <openssl/store.h>

=head1 DESCRIPTION

Support for the 'file' scheme is built into C<libcrypto>.
Since files come in all kinds of formats and content types, the 'file'
scheme has its own layer of functionality called "file handlers",
which are used to try to decode diverse types of file contents.

In case a file is formatted as PEM, each called file handler receives
the PEM name (everything following any 'C<-----BEGIN >') as well as
possible PEM headers, together with the decoded PEM body.  Since PEM
formatted files can contain more than one object, the file handlers
are called upon for each such object.

If the file isn't determined to be formatted as PEM, the content is
loaded in raw form in its entirety and passed to the available file
handlers as is, with no PEM name or headers.

Store 'file' also supports load of symmetric keys from arbitrary files. As
symmetric keys don't have any structure and encapsulation, the interpretation
of a file as a symmetric key should be requested explicitly via
L<OSSL_STORE_expect(3)>.

When loading from a file, symmetric keys are limited to 2048 bytes in length.

Each file handler is expected to handle PEM and non-PEM content as
appropriate.  Some may refuse non-PEM content for the sake of
determinism (for example, there are keys out in the wild that are
represented as an ASN.1 OCTET STRING.  In raw form, it's not easily
possible to distinguish those from any other data coming as an ASN.1
OCTET STRING, so such keys would naturally be accepted as PEM files
only).

=head1 NOTES

When needed, the 'file' scheme loader will require a pass phrase by
using the B<UI_METHOD> that was passed via OSSL_STORE_open().
This pass phrase is expected to be UTF-8 encoded, anything else will
give an undefined result.
The files made accessible through this loader are expected to be
standard compliant with regards to pass phrase encoding.
Files that aren't should be re-generated with a correctly encoded pass
phrase.
See L<passphrase-encoding(7)> for more information.

=head1 SEE ALSO

L<ossl_store(7)>, L<passphrase-encoding(7)>, L<OSSL_STORE_expect(3)>

=head1 HISTORY

Support for reading symmetric keys from files was added in OpenSSL 4.0

=head1 COPYRIGHT

Copyright 2018-2025 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>.

=cut
