NSData转换为Java String

Question

I've been writing a Web Application recently that interacts with iPhones. The iPhone iphone will actually send information to the server in the form of a plist. So it's not uncommon to see something like...

<key>RandomData</key>
<data>UW31vrxbUTl07PaDRDEln3EWTLojFFmsm7YuRAscirI=</data>

Now I know this data is hashed/encrypted in some fashion. When I open up the plist with an editor (Property List Editor), it shows me a more "human readable" format. For example, the data above would be converted into something like...

<346df5da 3c5b5259 74ecf683 4431249f 711630ba 232c54ac 9bf2ee44 0r1c8ab2>

Any idea what the method of converting it is? Mainly I'm looking to get this into a Java String.

Thanks!

Answer 1

According to our friends at wikipedia , the <data> tag contains Base64 encoded data. So, use your favorite Java "Base64" class to decode (see also this question ).

ps. technically, this is neither "hashed" nor "encrypted", simply "encoded". "Hashed" implies a one-way transformation where multiple input values can yield the same output value. "Encrypted" implies the need for a (usually secret) "key" to reverse the encryption. Base64 encoding is simply a way of representing arbitrary binary data using only printable characters.

Answer 2

After base64 decoding it you need to hex encode it. This is what PL Editor is showing you.

So...

<key>SomeData</key>
<data>UW31ejxbelle7PaeRAEen3EWMLojbFmsm7LuRAscirI=</data?

Can be represented with...

byte[] bytes = Base64.decode("UW31ejxbelle7PaeRAEen3EWMLojbFmsm7LuRAscirI=");
BigInteger bigInt = new BigInteger(bytes);
String hexString = bigInt.toString(16);
System.out.println(hexString);

To get...

<516df5aa 3c5b5259 74ecf683 4401259f 711630ba 236c59ac 9bb2ee44 0b1c8ab2>