BIO_new_CMS(3)

BIO_new_CMS(3)               OpenSSL               BIO_new_CMS(3)

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

1.0.2t               Last change: 2019-09-10                    1

BIO_new_CMS(3)               OpenSSL               BIO_new_CMS(3)

     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

1.0.2t               Last change: 2019-09-10                    2