Since App Engine is so blocked, I assume that there is no way to install an SSL certificate to allow credit card payments. In the absence of this, how can you protect payments with pens in the App Engine application?
http://code.google.com/appengine/docs/java/config/webxml.html#Secure_URLs says that
<ssl-enabled>true</ssl-enabled>
appengine-web.xml *.appspot.com. Google , FYI. Google Apps HTTPS , appspot .
, ! appspot, Google -, , , .
App Engine SSL . : https://developers.google.com/appengine/docs/ssl
, . (VIP - $99 ) , (SNI - $9 ) . : http://en.wikipedia.org/wiki/Server_Name_Indication#Support
, . Cloudflare.com SSL. HTTPS Cloudflare, HTTP App Engine. , , - CF GAE. : http://blorn.com/post/20185054195/ssl-for-your-domain-on-google-app-engine