Knowing pre-encryption data, can we find the private key CryptoLocker used?

One of our users seems to have been hit by CryptoLocker. As a result, he has a hard drive full of encrypted files. The ransom-ware claims to have used public key encryption on the files.

If we know exact contents of some of the files prior to them being encrypted, would it be feasible to use those files to discover the private key?

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No, if they implemented asymmetric encryption properly, such attacks are not possible. –  CodesInChaos Oct 24 '13 at 16:57
Read up on known plaintext attacks. If the files have been encrypted with a modern symmetric cipher (likely) such as AES, you're out of luck. –  hunter Oct 24 '13 at 17:48

The malware seems to do its cryptography by the book, so there is no way to recover your scrambled files once it has triggered. according to the link provided –  rath Oct 24 '13 at 23:14