[class-dump][1] is a great tool for getting information about how private frameworks work that you may want to use. For example, iPhotoAccess.framework gave among other classes the following:
`
@interface Base64 : NSObject
{
}
+ (id)stringForBase64:(id)fp8;
+ (id)base64ForString:(id)fp8;
@end
`
[1]: http://www.codethecode.com/projects/class-dump/