algorithms aes is popular private key encryption algorithm it requires fixed length key and data string to have length that is multiple of bytes unfortunatelythis is not part of standard pythonmay be subject to (and other countries'export controls in binary form at this writingand is too large and complex topic for us to address in this text this makes it less than universally applicableat the leastshipping its binary installer with this book' examples package may require legal expertise and since data encryption is core requirement of pymailcgithis seems too strong an external dependency the real showstopper for this book' fourth editionthoughis that pycrypto is xonly system not yet available for python todaythis makes it unusable with the examples in this book stillif you are able to install and learn pycryptothis can be powerful solution for more detailssearch for pycrypto on the web httpssecure http transmissions provided you are using server that supports secure httpyou can simply write html and delegate the encryption to the web server and browser as long as both ends of the transmission support this protocolit is probably the ultimate encrypting solution for web security in factit is used by most -commerce sites on the web today secure http (httpsis designated in urls by using the protocol name rather than it is encrypted with the ssl secure sockets layer https is supported by most web browsers and can be configured in most web serversincluding apache and the webserver py script that we are running locally in this if ssl support is compiled into your pythonpython sockets support it with ssl module socket wrappersand the client-side module urllib request we met in supports https unfortunatelyenabling secure http in web server requires more configuration and background knowledge than we can cover hereand it may require installing tools outside the standard python release if you want to explore this issue furthersearch the web for resources on setting up python-coded https server that supports ssl secure communications as one possible leadsee the third-party crypto package' openssl wrapper support for password encryptionhttps in urlliband morethis could be viable alternative to manual encryptionbut it is not yet available for python at this writing also see the web for more details on https in general it is not impossible that some of the https extensions for python' standard web server classes may make their way into the python standard library in the futurebut they have not in recent yearsperhaps reflecting the classesintended roles--they provide limited functionality for use in locally running servers oriented toward testingnot deployment utility modules