Is NSUTF8StringEncoding pretty secure?

This Objective-C code comes from a sample program which shows how to retrieve Contacts from the iPhone's Address Book, then encrypt it using the attached code:

EncryptionCodeImage.tiff

I got the code from the project referenced on this page's "Github page here" link.

http://maniacdev.com/2012/02/open-source-ios-address-book-wrapper-library-providing-automatic-hashing-and-permission-alerts/


What type of encryption is this?  Is it as secure as AES encryption?

To use it, must I convert all data to strings? That probably would not be difficult since I need to write it to XML anyway...


Thanks.

P.S. I needed to attach an image since I could not attach the code in the body of the email not as an RTF.