I did not know this - Exchange 2012 DLP function now has "fingerprinting" capability.

I know Microsoft introduced DLP features in Exchange 2013 and now, in SP1 they have introduced "Fingerprinting".

Good job Microsoft.

I believe we will see the DLP feature becoming part of more and more enterprise products.

(Similarly, I am hoping the vendors would also add firewall functions like how Oracle is doing) 

SNIPPETS from the Article:-

The file that you provide is not uploaded or stored by Exchange - only the hash value is kept. Once the document is processed, you can use the new sensitive data type that it represents in DLP rules in exactly the same way as any of the out-of-the-box sensitive data types (like credit card or social security numbers) defined by Microsoft. The hash value that is generated can then be used to compare against documents that flow through the transport system and any rule that uses the sensitive data type associated with the hash value will "fire." 

The links below has more information:

http://windowsitpro.com/blog/exchanges-interesting-document-fingerprinting-feature