This is a follow-on from bug 63001 which was resolved invalid due to containing multiple issues. I am splitting them up into individual bugs as the requests seem reasonable and contained a good example. Related Ask thread:

http://ask.libreoffice.org/en/question/1119/

Quoting from the original report:

> The current digital signature feature in libre office seems to have limitations 
> for full functionality in respect of digital signatures. Office documents 
> typically need several signatures, say the gentleman who drafted, the gentleman 
> who proofread, the guy who accepted, and the guy who finally okayed. Basically, 
> a document requires multiple signatures. This provision is currently not there 
> in libre office. We need a system of signing in "APPEND" mode as well if the 
> digital signature has to be made more effective and widely acceptable.

Refer attachment 77281 [details].