Asynchrony Solutions Blog

Using TLS with Self-Signed Certificates or Custom Root Certificates in iOS

by hborders on February 4th, 2011 at 2:14 pm

Transport Layer Security (TLS), formerly Secure Sockets Layer (SSL), is the standard for encrypting and authenticating messages and identifying users and servers, all of which you do when you make an online purchase.  For example, if you want to buy something from Amazon, you connect to a server that your Domain Name System (DNS) server says is amazon.com and send them your order with your credit card.  However, in this simple transaction, a number of failures could occur: you might not be connected to the real Amazon server, someone might be watching packets for your order to steal your credit card number, or someone might rewrite your order to have your order shipped to their house.  Using TLS, you can be sure that the server to which you are connected is Amazon’s, that no one sees the contents of your order, and that Amazon can verify that the order they received is the one that you sent. This article uses code examples to show how Apple’s mobile operating system, iOS, supports TLS and what you need to do to add it to your iPhone/iPad application.

iOS supports TLS with built-in commonly trusted root certificate authorities (CAs). However, if you must talk to a server whose certificate cannot be validated with those root CAs or is self-signed, you must manually validate the server’s certificate.

You have two options available: add your server’s certificate to the keychain or perform validation manually. Regardless of your approach, you’ll need to include a DER-encoded X.509 public certificate in your app. In the  example below, it is named “ios-trusted-cert.der”) and create a SecCertificateRef with it. (If your server’s certificate is part of a chain to a root certificate authority, you should install the root certificate authority rather than your server’s certificate.)

Read more of this post

Tags: Apple, Certificates, CFNetwork, cocoa, iOS, Security, SSL, TLS

Thoughts After a Week with the iPhone 4

by James Rantanen on July 14th, 2010 at 11:14 am

Differences from a 3GS
The first noticeable difference about the iPhone 4 is the construction. Gone is the plastic back construction of the previous two iPhone models, replaced by strengthened glass sheets on the front and back with a stainless-steel band around the edge. The screen of the iPhone 4, like that of the 3GS, should be very resistant to scratches, but early reports indicate that the latest model may be more susceptible to cracked glass when dropped, so get a case if you are worried about dropping your phone (that goes for just about any smartphone). The volume buttons and ringer on/off switch feel much more solid than those of the iPhone 3GS, which felt fairly cheap.

Read More of This Post

Tags: android, Apple, iOS, iPhone, iphone 4, mobile, review