<Tr> <Td> 19 May </Td> <Td> 2005 </Td> <Td> NIST withdraws FIPS 46 - 3 (see Federal Register vol 70, number 96) </Td> </Tr> <Tr> <Td> April </Td> <Td> 2006 </Td> <Td> The FPGA - based parallel machine COPACOBANA of the Universities of Bochum and Kiel, Germany, breaks DES in 9 days at a $10,000 hardware cost . Within a year software improvements reduced the average time to 6.4 days . </Td> </Tr> <Tr> <Td> Nov . </Td> <Td> 2008 </Td> <Td> The successor of COPACOBANA, the RIVYERA machine, reduced the average time to less than a single day . </Td> </Tr> <Tr> <Td> July </Td> <Td> 2017 </Td> <Td> A chosen - plaintext attack utilizing a rainbow table can recover the DES key for a single specific chosen plaintext 1122334455667788 in 25 seconds . A new rainbow table has to be calculated per plaintext . A limited set of rainbow tables have been made available for download . </Td> </Tr>

3des takes three 64-bit keys for an overall key length of ____ bits