If you ever needed to upgrade the libssl library on your system this is how you can do it.
First add the Precise source repository to your apt sources.
Now we just run:
apt-src install libssl1.0.0 apt-src build libssl1.0.0
Compiling will take a little time, but after compilation you will have the following files available:
libssl1.0.0_1.0.1-4ubuntu3_amd64.deb libssl1.0.0-dbg_1.0.1-4ubuntu3_amd64.deb libssl1.0.0-udeb_1.0.1-4ubuntu3_amd64.udeb libssl-dev_1.0.1-4ubuntu3_amd64.deb libssl-doc_1.0.1-4ubuntu3_all.deb openssl_1.0.1-4ubuntu3_amd64.deb
So we can either install all the packages with dpkg or, we can, if you have read Creating your own local compiled packages repository you can just move those files to the folder described there and after that run the update script the new libssl will be available for installation in the system