Purpose

Obfuscate string literals in your Xcode project using two simple ruby scripts.

obfuscate.rb

This script obfuscates #define values in a file of your choice and replaces them with Base64 strings.

Example:

#define kSomeConstant @"some_clear_text"

will become

#define kSomeConstant deobfuscate(c29tZV9jbGVhcl90ZXh0)

In addition, the script appends the deobfuscate() macro to the end of the file. This macro deobfuscates the hashed strings at runtime. The macro makes use of NSString(Base64) category so you must include that class in your project.

deobfuscate.rb

This script reverses the obfuscation performed by obfuscate.rb.

Base64 is a set of categories that provide methods to encode and decode data as a base-64-encoded string.

How to use

1. Add "Run Script" build phase for obfuscate.rb
   Open your Xcode project's "Build Phases" and add build phase for "Run Script". Copy and paste the contents of obfuscate.rb into the script body, and set the shell command to /usr/bin/ruby. This script must be run before "Compile Sources". Make sure to set the value of defines_file in the script to relative path of the file you wish to obfuscate.

2. Add "Run Script" build phase for deobfuscate.rb
   Create another "Run Script" build phase with the contents of deobfuscate.rb. This run script must run after "Compile Sources". You can put it as the last phase of the build.
   Make sure to set the value of defines_file in the script to the same value as in obfuscate.rb.

3. Add #import "Base64.h" to your defines_file and import Base64.h and .m files into your project.

Supported OS & SDK Versions

• Supported build target - iOS 6.0 / Mac OS 10.8 (Xcode 4.5, Apple LLVM compiler 4.1)
• Earliest supported deployment target - iOS 5.0 / Mac OS 10.7
• Earliest compatible deployment target - iOS 4.3 / Mac OS 10.6

NOTE: 'Supported' means that the library has been tested with this version. 'Compatible' means that the library should work on this iOS version (i.e. it doesn't rely on any unavailable SDK features) but is no longer being tested for compatibility and may require tweaking or bug fixes to run correctly.

ARC Compatibility

As of version 1.1, Base64 requires ARC. If you wish to use Base64 in a non-ARC project, just add the -fobjc-arc compiler flag to the Base64.m file. To do this, go to the Build Phases tab in your target settings, open the Compile Sources group, double-click Base64.m in the list and type -fobjc-arc into the popover.

If you wish to convert your whole project to ARC, comment out the #error line in Base64.m, then run the Edit > Refactor > Convert to Objective-C ARC... tool in Xcode and make sure all files that you wish to use ARC for (including Base64.m) are checked.

Thread Safety

All the Base64 methods should be safe to call from multiple threads concurrently.

NSData Extensions

Base64 extends NSData with the following methods:

+ (NSData *)dataWithBase64EncodedString:(NSString *)string;

Takes a base-64-encoded string and returns an autoreleased NSData object containing the decoded data. Any non-base-64 characters in the string are ignored, so it is safe to pass a string containing line breaks or other delimiters.

- (NSString *)base64EncodedStringWithWrapWidth:(NSUInteger)wrapWidth;

Encodes the data as a base-64-encoded string and returns it. The wrapWidth argument allows you to specify the number of characters at which the output should wrap onto a new line. The value of wrapWidth must be a multiple of four. Values that are not a multiple of four will be truncated to the nearest multiple. A value of zero indicates that the data should not wrap.

- (NSString *)base64EncodedString;

Encodes the data as a base-64-encoded string without any wrapping (line breaks).

NSString Extensions

Base64 extends NSString with the following methods:

+ (NSString *)stringWithBase64EncodedString:(NSString *)string;

Takes a base-64-encoded string and returns an autoreleased NSString object containing the decoded data, interpreted using UTF8 encoding. The vast majority of use cases for Base64 encoding use Ascii or UTF8 strings, so this should be sufficient for most purposes. If you do need to decode string data in an encoding other than UTF8, convert your string to an NSData object first and then use the NSData dataWithBase64EncodedString: method instead.

- (NSString *)base64EncodedStringWithWrapWidth:(NSUInteger)wrapWidth;

Converts the string data to UTF8 data and then encodes the data as a base-64-encoded string and returns it. The wrapWidth argument allows you to specify the number of characters at which the output should wrap onto a new line. The value of wrapWidth must be a multiple of four. Values that are not a multiple of four will be truncated to the nearest multiple. A value of zero indicates that the data should not wrap.

- (NSString *)base64EncodedString;

Encodes the string as UTF8 data and then encodes that as a base-64-encoded string without any wrapping (line breaks).

- (NSString *)base64DecodedString;

Treats the string as a base-64-encoded string and returns an autoreleased NSString object containing the decoded data, interpreted using UTF8 encoding. Any non-base-64 characters in the string are ignored, so it is safe to use a string containing line breaks or other delimiters.

- (NSData *)base64DecodedData;

Treats the string as base-64-encoded data and returns an autoreleased NSData object containing the decoded data. Any non-base-64 characters in the string are ignored, so it is safe to use a string containing line breaks or other delimiters.