"All attempts by Japan and Europe have failed so far.."
Ermm....Mars Express has been in orbit there for 5 years...
http://www.esa.int/SPECIALS/Mars_Express/index.html
3 publicly visible posts • joined 31 Mar 2011
Yes because there were clearly no transfer of legal documents before email was invented so none of those options are credible.....
It's a question of duty of care - if you use a courier, or *registered* mail (or recorded delivery) then you have exercised reasonable care in transporting sensitive material. If you elect to transfer the material yourself through the use of unencrypted email and have no checks in place to confirm you are sending to the correct address then you have *not* demonstrated a reasonable duty of care.