You could ssh into a shell on the machine and run from that account. If you have higher security requirements you can use a vpn maybe but for what it sounds like you are doing, if everything is always patched up to date it sounds fine, especially if it is only opened at certain times. Presumably if you limit to your dsl provider's block you can reduce risk. Dyndns sounds okay too though of course you have no idea about what it would take to get into their system. As for the blob, I have used a module I wrote called Quickcrypt which includes a sub called websafepack/websafeunpack to store serialized structures in html forms. The websafe part comes from using a web-safe alphabet ("charset") like that used by
CGI::EncryptForm, and the serialized data is IIRC gpg encyrypted before applying that. I am not sure a bare MIME64 will do enough.. try it a little it seems there was a problem with just the base64-quotable. On the other hand if you can upload a file via post you can upload a structure serialized into a text file, so the extra alphabet is only for embedding into an HTML form field. Why not try serializing your structure to disk for safekeeping, then upload that file to the server? Straight uploading could be done by sftp, with files grabbed by a running daemon, or you can do what you were going to do and POST it up there or use some other protocol and have the receiving program do the processing for you.