Can anyone tell me what encoding this is?

Question

AAAAAAFuAAIAAAZNYWMgT1MAAAAAAAAAAAAAAAAAAAAAAAAAAADMrsHTSCsAAAALuG8NYWxleHN1Y2tzLmRpYwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAPJXS83SjIoAAAAAAAAAAP////8AAAkgAAAAAAAAAAAAAAAAAAAAB0Rlc2t0b3AAABAACAAAzK6zwwAAABEACAAAzdJ+egAAAAEADAALuG8AC7hIAADK3wACADFNYWMgT1M6VXNlcnM6AGFuZHJld3ByeWRlOgBEZXNrdG9wOgBhbGV4c3Vja3MuZGljAAAOABwADQBhAGwAZQB4AHMAdQBjAGsAcwAuAGQAaQBjAA8ADgAGAE0AYQBjACAATwBTABIAJ1VzZXJzL2FuZHJld3ByeWRlL0Rlc2t0b3AvYWxleHN1Y2tzLmRpYwAAEwABLwAAFQACABL//wAA

It's a data field from the ~/Library/Preferences/com.microsoft.office.plist file for Microsoft Office 2011 Mac.

It partially decodes using base64 but doesn't appear to be completely base64.

Edit: Here is another example.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<data>AAAAAAFWAAIAAAZNYWMgT1MAAAAAAAAAAAAAAAAAAAAAAAAAAADMrsHTSCsAAAALuG8HMm5kLmRpYwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAPgev83SjIoAAAAAAAAAAP////8AAAkgAAAAAAAAAAAAAAAAAAAAB0Rlc2t0b3AAABAACAAAzK6zwwAAABEACAAAzdJ+egAAAAEADAALuG8AC7hIAADK3wACACtNYWMgT1M6VXNlcnM6AGFuZHJld3ByeWRlOgBEZXNrdG9wOgAybmQuZGljAAAOABAABwAyAG4AZAAuAGQAaQBjAA8ADgAGAE0AYQBjACAATwBTABIAIVVzZXJzL2FuZHJld3ByeWRlL0Rlc2t0b3AvMm5kLmRpYwAAEwABLwAAFQACABL//wAA</data>
</plist>

Answer 1

base64 is usually used to encode decode binary files like images. As you would have seen on decoding the above file, it contains few recognizable ASCII strings but most of it is binary.

Property list is a format for storing serialized objects. It is also used for storing settings in Office 2011 Mac. If you are interested in the details for this particular file you can check it here. Scroll to ~/Library/Preferences/com.microsoft.office.plist for the specific format details.

This will help you understand what the ASCII strings mean. To extract and view the plist completely (even binary part) you can use Property List Editor and plutil. (See the source). There are several programs which can do the same.

But if you need to learn how to read and write from plist file (Property List), you can check these links:

1. http://en.wikipedia.org/wiki/Property_list
2. http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/PropertyLists/Introduction/Introduction.html

Answer 2

It appears to be Base64. The decoded string is

    n   Mac OS                     Ì®ÁÓH+   ¸o
alexsucks.dic                                                   òWKÍÒŒŠ        ÿÿÿÿ                     Desktop     Ì®³Ã      ÍÒ~z     ¸o ¸H  Êß  1Mac OS:Users: andrewpryde: Desktop: alexsucks.dic    
 a l e x s u c k s . d i c    M a c   O S  'Users/andrewpryde/Desktop/alexsucks.dic   /    ÿÿ