CMS_sign/CMS_final streaming

[Dirk-Willem van Gulik]

I have very large globs  of on the fly generated data that are to be signed and output as a base64 payload followed by a separate PKCS#7 package with a detached signature at the end of the transmission[1].

I’d like to avoid CMS_sign/CMS_final having to rely on a BIO_s_mem(), disk-storage or similar. 

But rather simply do something like calculating the SHA256 as the payload is streamed out.  And then have a CMS_sign/final do the deed with that SHA256 rather than a BIO. 

Is there a way to use these interfaces (or ex) that way ? 

With kind regards,

Dw

1: https://source.redwax.eu/svn/redwax/rs/mod_cms_sign/trunk/mod_cms_sign.c