Is HTTPS protocol relevant for REST API Webservices?

Question

I have a HTTP REST API in PHP used by an iPhone application.

Some webservices from this API are secured with a user authentication in the HTTP request credentials but I want to avoid "man in the middle" attacks by providing fully encrypted requests data.

I'm not really skilled in security issues and I couldn't find any clear answer to my question anywhere :

Is HTTPS relevant for STATELESS REST API ?

From what I understood, HTTPS does 2 things :

• encrypt your session
• prove to the client that the server he is talking to is secured

So at first sight it does not respond to my need which is to encrypt the data between my server and the application because the API does not use sessions. But I still have doubts.

Can someone make it clear to me ?

My other solution would by to encrypt requests data with public/private keys system. Would it be more suitable ?

Thank you !

Answer 1

Definitely use, HTTPS if the data is sensitive - it encrypts at the transport layer which is what you are looking for. As already pointed out oAuth 2.0 mandates it essentially. You can potentially avoid man in the middle by using hashing/signing as in oAuth 1.0 and avoid having to use SSL but the body still goes in the clear then (you've avoided sending the API credentials in the clear but not the body).

Answer 2

If you do not want to implement SSL you may want to check out http://www.jcryption.org/ I don't know if it will work in a stateless environment, but may be worth a try. It is basically a jquery plugin that handles creating key pair associations for data being transmitted. May only be for form submission though. We used to use it to encrypt login credentials at my old company.

Answer 3

Yes, it is. HTTPS has nothing to do with the application, it's a tunneling protocol. Even though TLS is itself a stateful protocol, the HTTP part going over it is not.

Just like if you were using a VPN, you can still have a REST based application. The TLS just sets up and tears down the tunnel automatically for each connection.

That said, there's value in leveraging the pipelining aspects of HTTP and HTTPS to improve throughput over TLS connections, but that's a performance tuning aspect unrelated to the application itself.

Answer 4

HTTPS is very relevant, and yes, that's because of the two points you mentioned. Did you know that OAuth 2 actually enforces HTTPS?

Doing all the encryption yourself could be an option as well, but you lose the part where the API is easy to use.

Most man-in-the-middle attacks on "simple" HTTP requests involve stealing credentials and faking requests, but they can also read the data sent and received. If your issue is with the data being unreadable, use HTTPS. If fake requests are the only problem, an authentication protocol such as OAuth 1 (not 2) would suffice.