Smart card interface, why so many daemons ?

[Laurent Pinchart]

Hi everybody,

I've been trying (unsuccessfully so far) to get the Belgian eID card working 
with GnuPG. As I'm getting a better understanding of the way GnuPG handles 
smart cards, a question arises: why so many daemons ?

Using PC/SC, gpgsm requires the following daemons to be running (or starts 
them if they are not running):

- PC/SC
- pcsc-wrapper (not really a daemon here, but a separate process)
- scdaemon
- gpg-agent

My question is, why so many of them ? PC/SC is needed, but I don't see the 
point in pcsc-wrapper, and I'm not sure about scdaemon either.

I understand the argument that, for security reasons, GnuPG can't be made a 
library, but will stay a separate process (with gpgme helping to communicate 
with that process). Are there security issues with scdaemon and 
pcsc-wrapper ?

Any info about the reasons smart card support has been architectured that way 
are welcome.

Laurent Pinchart