PROJECT BY: JAMES TOWNSENDCSE704 SPRING 2011

COMPLETED UNDER DR. RUSS MILLER

Using MPI to Break Data Encryption

Data Security

Cryptography has been used as far back as Julius Caesar

Important data cannot be sent in plaintextIn 1976 a standard was created by the NSB,

now NISTIBM was internally using the Lucifer cipherAdapted as the Data Encryption Standard

(DES)

About DES

DES is a symmetric block cipher, meaning the two communicating parties share a key I.E. one key encrypts and decrypts blocks

Messages are encrypted by breaking them into individual 64 bit blocks (8 characters)

Each block is encrypted with a 56 bit key with 8 parity bits

This encrypted message can then be transmitted without worry

Controversy Around DES

Original submitted cipher used 128 bit keysNSA reduced the size to 56 bits and hid the

internal design of the substitution boxesSome believed they did this so they could

somehow decode all of the encryptionsControversy was not calmed until the release

of the internal design of the algorithmMany still believed it was not secure

Cryptanalysis of DES

Cryptanalysis is the process of mathematically attacking the algorithm to find weaknesses Goal is to discover a connection between plaintext and

cipher text that would be faster than brute forceOver 30 years of dedicated work has been put

into cryptanalyzing DES with no significant results Differential Cryptanalysis was discovered in 1990 NSA and IBM knew of it 20 years earlier and designed

DES to be resistant to this attack

Brute Force Attacks

Process of searching the entire key-space to find the correct key

In 1976 it was inconceivable to attack Even in 1990, estimates were almost 2500 years for a

single computer to brute force DESProposals were made as early as 1977 that a

$20 million machine could brute force DES in a day In 1990, the numbers were down to $1 million

machine that could break it in 7 hours None of these machines were publicly built

Distributed.net

Non-profit organization dedicated to solving large-scale problems

Created a version of grid computing where people could volunteer their idle computer cycles to help search the key-space for a reward

In 1997, the efforts of dsitributed.net cracked a DES encryption in 96 days

In 2001, had an estimated throughput of over 30 teraflops

How They Succeeded

They used the combined efforts of 78,000 computers

Users could log on and let their idle cycles be used trying different keys

The person whose computer found the correct key would get $4000 in prize money

Through this crowd-sourcing type of cracking, great strides were made in making a public outcry

EFF

The Electronic Frontier Foundation is a cyberspace civil rights group

Leading crusaders for the need of a new algorithm

First to publicly implement a custom DES breaker

Used this machine to break a cipher in just 56 hours in 1998

How They Succeeded

They built Deep Crack for just under $250,0001500 “Deep Crack” chips would each search

different keys and eliminate false-positivesA head node would periodically retrieve the

possibilities from the chips and run the full decryption on them

Over 37,000 search units were involved in the first decryption in 1998 24 Units per Deep Crack chip

In collaboration with distributed.net, just 22.5 hours for the third DES challenge

How It Worked

For each key, the nodes would decrypt the first block and check if it came as plaintext Returns as a 64 bit block If Plaintext, it would correspond to 8 characters of ASCII

code Normal English text falls into only 69 ASCII values Odds of a random key returning 8 bytes of ASCII code is just

1/65536If this succeeded, try the same with the second

Odds of all bytes returning as ASCII just 1 in 4 trillionAny keys that are still possibilities are returned to

a central processor that attempts to decrypt the full text

Implementing on the Edge Cluster

This approach is perfect for MPIThe Edge computer has the OpenSSL library

Contains many standard encryption techniques Can expand DES Cracker to test the survivability of

many other algorithms Dividing the key-space among all of the nodes and

report back the possible keys For theoretical purposes, I kept track of the keys

searched to estimate the total time needed

Results

Searched 34.3 billion keys One 2 millionth of the key-space

Almost perfect speedup is achievedOnly communication step is to sum up the

counted possibilities and make sure all nodes reported results

Differences in speedup factors likely due to load balancing issues as the regions are divided

DES Results

8 16 24 32 40 48 56 640

5

10

15

20

25

30

Time to Run 268 Million Keys

Sec

PEs

Seconds

Processors

DES Results

1 8 16 24 32 40 48 56 640

10

20

30

40

50

60

70

80

90

Total Keys per Second

Keys/Sec

Keys/

Second (

In M

illi

ons)

DES Results

0 20 40 60 80 100 120 1400.9

0.92

0.94

0.96

0.98

1

1.02

Speedup

Speedup

Processors

Implications

A single node is capable of searching roughly 1.1 million keys per second In comparison, each Deep Crack node searching 2.5

million keys per second Shows the large difference between running DES in

specialized hardware vs. softwareHowever, using 64 PEs, over 80 million keys

per second are possibleUsing an entire 1024 PE Edge partition,

roughly 1.2 billion keys could be tested every second

Implications

Using a completely general purpose parallel computer, it is possible to approach the key search speeds Deep Crack was able to achieve

Utilizing an entire Edge partition could crack DES on average in just 9 months The Edge partition has a total of just 1024 PEs, compared to

the 37000 search units on the original Deep Crack machineThis is still just using non-optimized software

versions of the algorithm OpenSSL focuses on usability, not efficiency Hardware encryption would still take less than half the time

of even optimized software encryption

Introduction of AES

The Advanced Encryption Standard was brought about largely by the efforts of Deep Crack and Distributed.net

A new algorithm using a much larger key size (variably 128-256 bits) was selected from a publically submitted contest

Much of the controversy that surrounded DES was mitigated by this open-source process

Implementation on Edge

Algorithm followed the same concept as the DES Cracker

Blocks are twice as many bits, so using 2 blocks is even less likely to be all ASCII by chance that DES Returned only 41 possibilities out of 4 trillion keys just

by checking the first two blocks Keys were harder to determine because only

a portion of the key is used per round, but that was accounted for in the process

AES Results on the Edge

8 16 24 32 40 48 56 640

100

200

300

400

500

600

Time to Run 4.3 Billion Keys

Seconds

PEs

Seconds

AES Results on the Edge

1 8 16 24 32 40 48 56 640

10

20

30

40

50

60

70

Total Keys/Second

PEs

Keys/

Second (

In M

illi

ons)

AES Results on the Edge

0 10 20 30 40 50 60 700.93

0.935

0.94

0.945

0.95

0.955

0.96

Speedup

PEs

Speedup F

acto

r

AES Expansion to GPGPUs

GPGPUs (General Purpose Graphics Processing Units) offer an exciting opportunity for parallel computing

Consist of CPUs extremely limited in processing power, streamlined for very fast, simple computations

Perfect for simple parallel tasks, such as encrypting files with AES

AES Expansion to GPGPUs

NVIDIA is a leader in scientific computing on GPGPUs Opened the CUDA language to developers to run on

their video cardsDr. Russ Miller has headed a project to create

a supercomputer at the University at Buffalo using NVIDIA cards as the processing power Entitled the MAGIC computer

AES Cracker Implementation

For simplicity, I used my personal computer with a CUDA-enabled NVIDIA card as a test subject Performed on a NVIDIA 9500GT

I was able to find an open-source AES implementation that was suited for a similarly styled AES Cracker

Many optimizations still had to be made to decrypt with many keys per one block, as opposed to many blocks with one key

AES Results on GPGPU

36 Million keys per second on a single GPGPU

By comparison, it took 40 nodes to reach 37 Million keys per second

Extrapolating the numbers, it would take 2.85x10^23 years for a single card to search the entire keyspace

The Edge machine would take 1.1x10^22, a savings of just one order of magnitude

GPGPU Supercomputers- Magic

The University at Buffalo Cyberinfrastructure Laboratory has a nVidia Tesla/Intel Xeon cluster Hybrid GPGPU/Central Processor Hierarchy of Dell PE1950s controlling 15 nVidia Tesla

S1070s Approximately 57.5 TFLOPS Total cost of the system was under $100,000

Extension to MAGIC Computer

nVidia GeForce 9500 GT – 134.4 GFLOPSnVidia Tesla S1070 – 4147.2 GFLOPS

Each of the 15 nodes are a 30 times faster Instead of just 36 Million keys/second, MAGIC is

capable of more than 16.7 Billion keys/secondAs GPGPUs become more widespread, speeds

will continue to skyrocket as prices will begin to plummet Tesla S2050 cards already reach 5152 GFLOPS

Comparison Between Computers

The partition of the Edge computer used consists of 128 dual-quad core nodes Each node cost upwards of $3500 Total machine cost over $400,000 More expensive partitions also exist

A Theoretical limit of just over 9000 GFLOPS for $400,000 compared to MAGICs 57500 GFLOPS for just under $100,000 This shows the real potential for GPGPU

supercomputing opportunities

Conclusion

DES is certainly no longer secure due to the efforts of DeepCrack and Distributed.net, as well as the dramatic role GPGPUs will continue to play in the supercomputer market

AES is still a very strong algorithm that is completely infeasible to crack by current measures Even the MAGIC system would take 6x10^20 years to search the entire

keyspace Continuing advances in GPGPU supercomputing will make

attempts at building a successful AES cracker more realistic, but will not be successful anytime soon Currently would take 10^21 GPGPUs to reduce the time to crack to within a

single year Even if the 128 bit key size becomes obsolete, 192 and 256 bit

key versions are already in use and can be easily adopted universally These key sizes would eliminate the chance of insecurity exponentially

References

EFF and Deep Crack http://w2.eff.org/Privacy/Crypto/Crypto_misc/DESCracker/HTML/19980716_eff_des_faq.html

DES Information http://en.wikipedia.org/wiki/Data_Encryption_Standard

Standard DES and AES Implementations in C www.openssl.org

RSA Security DES Challenges http://en.wikipedia.org/wiki/DES_Challenges

Distributed.net http://en.wikipedia.org/wiki/Distributed.net

AES Information http://en.wikipedia.org/wiki/Advanced_Encryption_Standard

Standard AES Implementation in CUDA http://shader.kaist.edu/sslshader/libgpucrypto/

Center for Computational Research www.ccr.buffalo.edu

CyberInfrastructure Laboratory http://www.cse.buffalo.edu/faculty/miller/CI/equipment.shtml

nVidia Specifications http://www.nvidia.com/object/why-choose-tesla.html http://en.wikipedia.org/wiki/Comparison_of_Nvidia_graphics_processing_units

Intel L5520 Specifications http://www.tecchannel.de/bild-zoom/2019750/11/382245/il-80380865738247327/

Thanks to Dr. Russ Miller, Kevin Cleary, and Matt Jones for specifications and costs of the CCR systems