Updated: 2021/Apr/14

BIO_new_CMS(3)                      OpenSSL                     BIO_new_CMS(3)

       BIO_new_CMS - CMS streaming filter BIO

       libcrypto, -lcrypto

        #include <openssl/cms.h>

        BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);

       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.

       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

       There is currently no corresponding inverse BIO: i.e. one which can
       decode a CMS structure on the fly.

       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).

       ERR_get_error(3), CMS_sign(3), CMS_encrypt(3)

       The BIO_new_CMS() function was added in OpenSSL 1.0.0.

       Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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

1.1.1i                            2019-03-12                    BIO_new_CMS(3)