Question

Want to have a ssl C# server that will only send and receive small JSON strings.

The clients can be anything from mobile devices or computers.

Need some feedback what to chose since some clients maybe have ssl limitations or other limitations.

Should i create an (openssl)ssl ftp socket server?
Should i create an HTTPs server?
should i create something else????

The HTTPS looks like easiest because of it’s long history and width usage.

any feedback would be grate

Answer 1

HTTPS is HTTP over SSL/TLS: you first establish an SSL/TLS connection and then you exchange HTTP requests and responses on top of it (as if it was a plain TCP connection).

Since you want to use SSL/TLS in both cases, what you seem to be asking is whether you should design your own protocol or use an existing one.

Should i create an (openssl)ssl ftp socket server?

There are multiple ways of securing FTP with SSL/TLS. It’s certainly not the easiest way to go.

Should i create an HTTPs server? should i create something else????

Designing your own protocol means that you’ll have to provide an implementation for each device yourself. HTTPS has the advantage of being widely supported. You shouldn’t even have to use much of the underlying SSL/TLS API yourself (no need to learn the OpenSSL API). The only requirements might be to learn about some SSL/TLS configuration, such as setting up certificates.

Even if you’re thinking of reducing the overhead due to the HTTP headers, your protocol will still have to perform similar payload management one way or another, at least to know where the requests and responses start and end.

It’s unclear what your requirements are, but unless you really notice problems with HTTPS, exchanging JSON strings with HTTPS with an existing library (e.g. WCF) makes more sense than your other suggestions.