In an application in Delphi 2006 I need to both upload and download files encrypted and after download stored encrypted, but transiently decrypted when needed at runtime. It will contain personal data like given name, surname, postal address (with street name), telephone number and mail address that should not be avaiable to user, unless when needed about a single member. The file will then be decrypted and needed info for the member will be extracted.
Using the weak mime64 encode, download works today, but I feel I need more security, starting with getting from server a random key for encryption in order to upload organisation member data that is to be updated. Due to EU regulation I have been told it has to be transferred strictly encoded since the transfer pass national borders.
But find it difficult to find encryption/decryption methods that is reversible in php. Most examples are for irreversible hashing/encryption of passwords
The server don't support secure transfer by itself (https).
What I do today is encrypt the file before transferring and decrypt at receive, using mime64 encode decode.
So what method should be chosen that is usable both in php and Delphi? Seem like blowfish encryption in php is just a one-way hash, while it is reversible in Delphi, at in Turbopower Lockbox.