Challenge: Decrypt this!

Having implemented a recent state-of-the art crypto system with a 5020 bit key, I feel sure that it is computationally safe.

It is a public key system, thus it is always breakable in the following sense: if you guess the original message text and encrypt it with my public key (and everybody can do so), you can by simple verification with the ciphertext determine whether your guess was right.

In this particular case, it is a bit more difficult; the encryption works probabilistic (and thus increases the length of the message by the factor 4).

I'm offering a prize for the one, who sends me my clear-text message:

1000 Danish Kroner

OK, this is not a hell lot of money in the cosmic sense (about 140 US dollars), but for me, being a poor PhD student, it is. So, I must be pretty sure you will never figure out, what the original text was, though I'm giving you a fair chance: You have full access to the used crypto system [CS98] (see here for a short overview) and to my public key. The crypto-text following is one 4x5020 bit block, encoded in standard base64. You can use the Base64Handler in MillstoneCrypter.java to decode it to a number (or any format you like).

If you should succeed (and you'll know; the original message does make sense):
Mail me the message text.
I promise, that the first one who sends this to me, will receive his/her 1000,- DKK. (And I'm not allowed to take part in this competition...)

Here comes the cypher-text:


Method:   Cramer-Shoup98
Key-Name: Millstone-5020
Owner:    M. Oliver Moeller <webmaster@verify-it.de>
begin-base64 CryptoText Input
RSU5hIW9BVa92H8AJcUHQ6Mz0uACgkk1QEnbPuyxI9u8byVYZg/64EGALDJ3tJa26h1OGoSlluJ51t
5bfo2eBuCT0Q7TGNrvRZ6m7ioagTW5UmdE3d4hAAkrSQUPZlw1Be1Q9PsU3KELjOtzhFCj6IFEVQ/5
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ACPvqlZFqFBH86sr9q4YFjNQ/Cr6hXHO4qq8wFnxcsz6eW3MQA9JPEwdk81PQuQMjfjt/bw=
==== 
P.S.: For those who are better at hacking than at cryptography: The original message text is not available on my Unix account and never was. No way of cheating here ;o)
[CS98] Ronald Cramer and Victor Shoup: A practical public key crypto system provably secure against adaptive chosen ciphertext attack. in proceedings of Crypto 1998, LNCS 1462, p.13ff
Counter started on 23/12/2001 Counter started on 23 December 2001
webmaster - Last modified: Mon Feb 10 23:28:12 2003