I have some cipher units written for Delphi 7.
These are fairly complex (at least for me). They contain methods (sorry
functions and procedures) for the elliptic curve asymmetric cipher, The
Rijndael symmetric cipher and the SHA-1 hash.
The system that uses these is using file downloads and uploads using
Delphi 7 Isapi dlls.
The system while working, is suffering congestion problems especially
with uploads.
What I would like to use is WCF web services to handle data downloads
and create local server files from parameters sent to the WCF web
service on the server rather than perform uploads (the file contents is
very small).
Writing the WCF should not be too much of a challenge but I need to use
the delphi code to handle decryption/encryption.
I thought of writing a Win32 dll for the encryption logic called from C#
WinForms (or maybe WPF) application.
Has anyone done this sort of thing before? I understand that value types
are ok to exchange but reference types are a pain, this includes strings.
I have googled and there is a fair bit out there. Most of this is
dealing with the pain of trying do it.
I only need to exchange ints, bools and strings. Nothing too fancy.
Has anyone some sample code they would be willing to share?
Also I would like be able call a method in the dll to store information
in memory to be used by other method calls. This information is stored
in an xml file and I would rather it be read and processed once rather
than repeat this each time I need to use a method. In other words in
using delphi dll, will it preserve state between method calls?
If I can't get the dll to work I will fall back on the crypographic
support in the framework but this basically triples the effort required
and data encrypted by the current system will not be compatible with the
framework cryptographic routines.
Any help very much appreciated.
