http://bkg5ofjslnbyqvu55sjonpdyp3wmfsgq23u7vpk3wxn7ewgdeocpgwid.onion?page=article&article=Encrypted+Messages+in+Public+Spaces%3A+The+Modern+Dead+Drop.html
Posting to a website or forum, after all, exposes the message to the entire world. However, encryption techniques ensure that only the intended recipient, who has the correct decryption key, can read the message.