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Sample PG file
Price:Performance Worksheet
Clustering Resources
Other Crackers


This page briefly outlines the cost of building a cheap beowulf-like cluster to use dkbf to crack NT passwords. The numbers used are general and for proof-of-concept only. Your mileage WILL vary. The numbers here are out-of-date, which is good for you - bad for sys admins.

A-Z consists of 26 characters. NT Lanman passwords only have 7 characters in them (see www.L0pht.com). This yields 8,353,082,582 possible "keys". At a (very approximate) rate of 446 k/s/Mhz on a Pentium Pro 200, the L0phtCrack requires 26 hours to brute-force the A-Z keyspace.

As of Dec 2000, the following items were priced using Pricewatch

    Price   Part                                Quantity     Cost
    $179    800 Mhz Pentium PIII                x8           1432
    $2      CPU Fans                            x8             16
    $125    Tyan Tiger 133 Dual CPU M/B         x4            500
    $42     128 MB PC-100 RAM                   x4            168  
    $45     3.2 GB EIDE HD                      x4            180  
    $10     10/100 Mb/s Ethernet NIC            x4             40 
    $5      Floppy Drive                        x4             20
    $10     PCI Video Card                      x4             40 
    $20     ATX Case w/ 230 Watt PSU            x4             80
    $4      Case Fan                            x4             16
    $20     4 port 10 Mb/s Ethernet Hub         x1             20
    $2      CAT 5 Ethernet Cables               x4              8
    $5      PS/2 Keyboard                       x1              5
    $5      Mouse                               x1              5
    $103    14 in. Monitor                      x1            103
    $30     Manual KVM Switch + cables          x1             30
    $24     x40 CD-ROM                          x1             24  
    $2      Scyld Beowulf CD                    x1              2 
    $30     Red Hat 7.0 Distribution            x1             30
                                                            $ 2719   

Of course, these numbers are rough. No shipping and handling is included which is a significant cost factor. You'll probably have some of these parts already. Estimate does not include replacement parts, warranties, or electricity costs. In other words, this is a rough estimate of cheap parts and keyrates.

Given a small cluster like the one above, which would have combined a 5600 Mhz (less one processor to handle the master process), and given a keyrate of 446 k/s/Mhz (incorrectly assuming perfect linear scaling), a total keyrate of 2,497,600 k/s could be achieved. The following Lanman hash attacks would take:

    Character Set       Keys                        Time 
    A-Z                 8,353,082,582 keys          1 hour
    A-Z,0-9             80,603,140,212 keys         9 hours
    A-Z,0-9,33 symbols  7,555,858,447,479 keys      35 days

Keyrates will vary with everything: RAM, CPU Mhz, CPU architecture, OS, load, compilers, number of accounts to be crackes, etc. LophtCrack does have much better numbers. Their program uses highly optimized assembly routines which are not used in dkbf. In addition, their benchmarks are on a Quad Xeon with 400 Mhz CPUs. If you have resources to buy a Quad Xeon, you'll get much better stats. However, Quad Xeon machines don't cost $3000.

Try it out for yourself with the Price:Performance Worksheet

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