iOS中OpenSSL

If your app depends on OpenSSL,you should compile OpenSSL yourself 
and statically link a known version of OpenSSL into your app. 
This use of OpenSSL is possible on both OS X and iOS. However, 
unless you are trying to maintain source compatibility with an existing open source project, 
you should generally use a different API.

苹果建议采用系统原生的

Common Crypto and Security Transforms are the recommended alternatives for general encryption.
 CFNetwork and Secure Transport are the recommended alternatives for secure communications.

如果你必须使用OpenSSL，可以直接源代码的形式或库的形式引入Xcode工程中。 参考OpenSSL-for-iPhone