Encrypt selected text within urxvt with gpg for the hidden recipient with given $pubKey (this is variable inside the script which have to be edited by hand) and upload the encrypted content to http://sprunge.us , there are other 2 websites that can be used instead sprunge.us, just uncomment the code and you'll be ready to rock. Since the recipient is hidden, anyone willing to extract metadata about the recipient will be out of luck. Only the recipient with the correct $pubKey can decrypt and read the content.

Installation

Simply place the script in /usr/lib/urxvt/perl/ for
system-wide availability or in ~/.urxvt/ext/ for user-only availability.
You can also put it in a folder of your choice, but then you have to add this
line to your .Xdefaults/.Xresources:

URxvt.perl-lib: /home/user/your/folder/
# extension to activate
URxvt.perl-ext-common           : encrypt

# keyboard shortcut to trigger the extension
URxvt.keysym.Control-Shift-G    : perl:encrypt:encrypt

Requirements

• urxvt (rxvt-unicode) compiled with support for perl