Distributed.net
The contests are associated with the distributed.net group, which had actively participated in the challenge by making use of distributed computing to perform a brute force attack.
RC5-32/12/7 was completed on 19 October 1997, with distributed.net finding the winning key in 250 days and winning the US$10,000 prize. The recovered plaintext was: The unknown message is: It's time to move to a longer key length.
RC5-32/12/8 also carried a US$10,000 prize and was completed by distributed.net on 14 July 2002. It took the group 1,757 days to locate the key, revealing the plaintext: The unknown message is: Some things are better left unread.
There were still eight remaining contests that had not yet been solved, RC5/32/12/9 through to RC5/32/12/16, each of which was a US$10,000 prize. Distributed.net had been working on RC5-32/12/9 and were over 1.950% through as of October 27, 2011.
Read more about this topic: RSA Secret-Key Challenge