BIO_new_CMS(3) OpenSSL BIO_new_CMS(3)NAMEBIO_new_CMS - CMS streaming filter BIO
BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);
DESCRIPTIONBIO_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 appro‐
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 parame‐
ter 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
Large numbers of small writes through the chain should be avoided as
this will produce an output consisting of lots of OCTET STRING struc‐
tures. Prepending a BIO_f_buffer() buffering BIO will prevent this.
There is currently no corresponding inverse BIO: i.e. one which can
decode a CMS structure on the fly.
RETURN VALUESBIO_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 ALSOERR_get_error(3), CMS_sign(3), CMS_encrypt(3)HISTORYBIO_new_CMS() was added to OpenSSL 1.0.0
1.0.0h 2009-10-01 BIO_new_CMS(3)