Converting between NSData and base64 strings

What is the easiest and fastest code to do a conversion between NSData and a base64 string? I've read a bunch of solutions at SO and mostly they involve in adding another class etc. I found a great solution here but it's too complex.

Scroll down to the Conclusion section on the page you linked and download the provided NSData+Base64 files. Its the best solution I have seen so far and is incredibly easy to use. If you can learn anything about Cocoa, you can learn to use that project.

Example

NSString *originalString = [NSString stringWithFormat:@"test"]; 
NSData *data = [NSData dataFromBase64String:originalString];  
NSLog([data base64EncodedString]); 

The above will print out the original string after converting it to base64 and back to a normal unencoded string.

As of iOS 7, NSData now directly provides this functionality with the new methods -base64EncodedDataWithOptions: and -base64EncodedStringWithOptions:. (The options let you specify that the string is/should be line-wrapped, the better to deal with email, and user-facing displays.)

You don't need any custom implementation. Creating base64 from NSData is shown in other answers. There is opposite direction. From Base64 string to NSData:

 NSString *base64Encoded = @"some base64 string";
 NSData *nsdataFromBase64String = [[NSData alloc] initWithBase64EncodedString:base64Encoded options:0];

I ended up using this same class as provided by SUDZC

implementation was easy first I did an import

 #import "NSData+Base64.h"

then I was able to call my data.

 NSData *data = [[NSData alloc] initWithData:[NSData dataWithBase64EncodedString:strData]];

Be aware that there are more Base64 formats.

For example JWTs use a URL safe format.