BIO_new_CMS
Section: OpenSSL (3)
Updated: 2017-05-25
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NAME
BIO_new_CMS - CMS streaming filter BIO
SYNOPSIS
#include <openssl/cms.h>
BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);
DESCRIPTION
BIO_new_CMS() returns a streaming filter
BIO chain based on
cms. The output
of the filter is written to
out. Any data written to the chain is
automatically translated to a
BER format
CMS structure of the appropriate type.
NOTES
The chain returned by this function behaves like a standard filter
BIO. It
supports non blocking I/O. Content is processed and streamed on the fly and not
all held in memory at once: so it is possible to encode very large structures.
After all content has been written through the chain
BIO_flush() must be called
to finalise the structure.
The CMS_STREAM flag must be included in the corresponding flags
parameter of the cms creation function.
If an application wishes to write additional data to out BIOs should be
removed from the chain using BIO_pop() and freed with BIO_free() until out
is reached. If no additional data needs to be written BIO_free_all() can be
called to free up the whole chain.
Any content written through the filter is used verbatim: no canonical
translation is performed.
It is possible to chain multiple BIOs to, for example, create a triple wrapped
signed, enveloped, signed structure. In this case it is the applications
responsibility to set the inner content type of any outer CMS_ContentInfo
structures.
Large numbers of small writes through the chain should be avoided as this will
produce an output consisting of lots of OCTET STRING structures. Prepending
a BIO_f_buffer() buffering BIO will prevent this.
BUGS
There is currently no corresponding inverse
BIO: i.e. one which can decode
a
CMS structure on the fly.
RETURN VALUES
BIO_new_CMS() returns a
BIO chain when successful or
NULL if an error
occurred. The error can be obtained from
ERR_get_error(3).
SEE ALSO
ERR_get_error(3),
CMS_sign(3),
CMS_encrypt(3)
HISTORY
BIO_new_CMS() was added to OpenSSL 1.0.0
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- NOTES
-
- BUGS
-
- RETURN VALUES
-
- SEE ALSO
-
- HISTORY
-
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