The document summarizes a presentation given on cryptographic failures. It introduces the speaker and provides context on cryptography. It then details three specific failures: 1) the use of MD5 for digital certificates led to forged certificates, 2) reuse of settings and keys undermined the security of the Enigma machine, and 3) flaws in WEP allowed wireless networks to be cracked. It also briefly mentions some other notable crypto failures and systems with weaknesses. The presentation used a lighthearted comic approach to explain the technical concepts.

1. @NTXISSA #NTXISSACSC4
A Brief History of
Cryptographic Failures
Brian Mork
CISO
Celanese
2016-10-07

2. @NTXISSA #NTXISSACSC4
Who Am I?
• CISO at S&P 500/Fortune 500 company
• Former air-drop hacker, security engineer,
penetration tester, RF simulation engineer,
electronics intelligence expert, optician’s
assistant, newspaper delivery boy, software
pirate, party organizer, and short order cook.
• Also known as “Hermit” within the
information security/hacker community
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3. @NTXISSA #NTXISSACSC4
DISCLAIMERS
• I’m not an expert in cryptography
• While I take cryptography seriously, I don’t
take myself seriously
• I used pictures from the Internet. I’ve listed
the sources I know on the second to last
slide.
• If we can’t have fun with this…
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4. @NTXISSA #NTXISSACSC4
Well, then…
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5. @NTXISSA #NTXISSACSC4
Agenda
• What is Cryptography?
• Why Cryptography?
• Our Cast
• The Failures
• Honorable Mentions
• Q&A
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6. @NTXISSA #NTXISSACSC4
What Is Cryptography?
“The process of writing or reading secret
messages or codes.”
- Miriam Webster Dictionary
“The art of writing or solving codes.”
- Oxford English Dictionary
“The scientific field of study related to
protecting or verifying information.”
- Brian Mork
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7. @NTXISSA #NTXISSACSC4
Why Cryptography?
• Because you lack trust in… something…
• Transmission mediums
• Integrity of communications
• Other people
• Governments
• Cigarette smoking men
• Etc.
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8. @NTXISSA #NTXISSACSC4
Our Cast
In traditional cryptographic discussions we
would consider the following actors:
• Alice – Someone sending information
• Bob – Someone receiving information
• Eve – Someone eavesdropping
All because Ron Rivest (of RSA fame) used
such terms back in the 1970s.
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9. @NTXISSA #NTXISSACSC4
Our REAL Cast
Times have changed, and we need heroes who
reflect those times…
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Alice, as… well… Alice
… Dilbert, as Bob …
… and Catbert, as Eve. Or
evil. Either one/both.

10. @NTXISSA #NTXISSACSC4
And now here’s something
we hope you’ll really like!
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11. @NTXISSA #NTXISSACSC4
Failure One
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REGULAR FAIL

12. @NTXISSA #NTXISSACSC4
The Scenario
Alice and Dilbert set up a secure website. It’s
amazing. It was hacker proof (just trust me on
this one), with an official certificate and
everything.
Unfortunately, their agents used browsers that
still trusted root certificate authorities that
used MD5 for hashing.
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13. @NTXISSA #NTXISSACSC4
Failure: MD5 Certificate
So what is MD5?
• Hashing algorithm
• Vulnerable to collisions
• Was still used through 2008 by certificate
authorities
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14. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
What is a collision?
It’s when two different inputs create the same
output.
Why is that bad?
Because… that’s exactly what it’s not
supposed to do!
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15. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
How can we make that worse?
By having a condition where two different
inputs share a function or format, such as
documents and executables
Or, I don’t know… cryptographic material
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16. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
The first MD5 collision was in 2004.
By 2007 colliding executables, documents, and
more were possible and had been
demonstrated, due to chosen-prefix collisions.
Enter the fake certificate authority!
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17. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
Step 1: Generate a pair of certificates with the
same hash but different characteristics (e.g.
make one a CA that can sign anything).
Step 2: Get the benign certificate signed by a
”real” CA and copy that signature to the
malicious one.
Step 3: Profit
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18. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
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19. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
And what does that give you?
A certificate that can sign literally anything, and
which validates back to a trusted root certificate
authority.
I am
Google
Microsoft
Mr. Robot
Whomever I want to be!
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20. @NTXISSA #NTXISSACSC4
Failure: MD5 Collisions
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I am Dilbert. You can
trust this because Alice
said I am. Now tell me
all your secrets.
They’re safe with me.

21. @NTXISSA #NTXISSACSC4
Failure Two
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22. @NTXISSA #NTXISSACSC4
The Scenario
• In an alternate dimension, Alice has
ascended to lead a military force against the
evil feline nation of Catbertia.
• Dilbert, her lead general, needs to
communicate securely with her.
• They decide to deploy one of the most
effective physical cryptographic systems ever
made… the enigmatic… er… Enigma.
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23. @NTXISSA #NTXISSACSC4
Failure X: Enigma
This is the Engima. It
was a beauty of
engineering. Multiple
rotors, each input
changed the next
encoding, easy to
operate and fiendishly
difficult to brute force.
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24. @NTXISSA #NTXISSACSC4
Failure X: Engima
How complex was it?
• 3 rotor wheel positions, 5 wheel choices (60
starting combinations)
• 26 starting positions per wheel (17,576
combinations)
• Wheels rotate one another… wiring to
create substitutions… egads!
• 107,458,687,327,250,619,360,000 keys
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25. @NTXISSA #NTXISSACSC4
Failure X: Engima
Oh, and then there was the fact that Engima
operations used key encrypting keys… really!
The day key was a pre-shared secret used to
encrypt one-time keys called message keys.
Message keys were then used to encrypt
actual messages.
Pretty nifty!
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26. @NTXISSA #NTXISSACSC4
Catbert Has No Chance!
• It’s true! With that many combinations and
frequency of change there’s no hope for the
empire of evil.
• Then again, people have been known to
make mistakes.
• But I’m sure Alice and Dilbert wouldn’t make
the same ones that their historical
predecessors did. What were those again?
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27. @NTXISSA #NTXISSACSC4
Failure X: Engima
How was Enigma previously defeated?
• Reuse of rotor settings
• Transmission with multiple ciphers
• Operators often reused the same message
key multiple times (e.g. “cillies”)
• Common message formats
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28. @NTXISSA #NTXISSACSC4
Failure X: Enigma
• What’s that? Dilbert has taken to using the
day of the week as the message key?
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29. @NTXISSA #NTXISSACSC4
Failure 2
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30. @NTXISSA #NTXISSACSC4
The Scenario
Alice and Dilbert are joining the modern age.
They visit each other’s houses frequently, and
use each other’s wireless networks.
To be extra safe, they’ve selected Wired
Equivalent Privacy (WEP) to secure their
network. What could possibly go wrong?
Well, since WEP uses a single key that needs
to be protected!
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31. @NTXISSA #NTXISSACSC4
Failure: WEP
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They know that Catbert is trying
to intercept their
communications, so they paid a
driver to take the out in the
middle of a mud field in Elbonia.
Once out there, they chose a
super secret password just
between the two of them. This is
now their wireless network
password.
Whew! That was close. Good
thing that sharing the key is the
biggest concern. Right?

32. @NTXISSA #NTXISSACSC4
Failure: WEP
Well, maybe not JUST that… there’s also:
• Poor initialization vectors (IV) size
• Weak IVs
• Weak key space
• Poor key entry (ASCII reduces key space)
• Replay/packet stimulation (when you need
more IVs)
• Chop-Chop Attack!
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33. @NTXISSA #NTXISSACSC4
Failure: WEP
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The only thing I like more
than weak crypto is my
enemies using it.

34. @NTXISSA #NTXISSACSC4NTX ISSA Cyber Security Conference – October 2-3, 2015 34
Will this guy ever shut up?

35. @NTXISSA #NTXISSACSC4
Honorable Mention
• Advanced Encryption Standard (AES) –
Electronic Codebook (ECB)
• Same key used over and over
• Block-based encryption
• Known plaintext lookup!
• SmashECB, for example (written by yours truly)
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36. @NTXISSA #NTXISSACSC4
Honorable Mention
• Clipper Chip – Law Enforcement Access Field
• Included data necessary to recover key
• Only 16-bit hash protecting it
• Bypass and reuse were possible and
demonstrated
• Use of third party LEAF data was possible too!
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37. @NTXISSA #NTXISSACSC4
Honorable Mention
• Microsoft’s ”Golden Key”
• Booting RT/ARM devices check two things: a
policy (must be signed by Microsoft) and the
operating system (also must be signed by
Microsoft)
• The “Golden Key” is a debug mode policy that
was accidentally shipped, and that policy allows
skipping the check for the operating system
• Presto! Any OS on a Surface/WinPhone/etc.
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38. @NTXISSA #NTXISSACSC4
Honorable Mentions
And so many, many more…
• WPA - Design
• Dual EC DRBG - Design
• MD4 – Time, mostly
• NIST P- curves (ECC) – Design
• Digital Encryption Standard (DES) – Design
• 3 DES – Design
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39. @NTXISSA #NTXISSACSC4
Questions
If you’ve got ’em, throw ‘em.
If I know the answer, I’ll give it.
If I don’t, I’ll answer anyways before I disclose
that I have no clue what I’m talking about.
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40. @NTXISSA #NTXISSACSC4
Miscellaneous
• Picture Credits
• Mulder Image: Pascal Wagler
• Dilbert Characters: Scott Adams
• Engima Machine: TheHistoryBlog.com
• Failure Pictures: The Internet Tubes
• Find Me
• Twitter: @hermit_hacker
• LinkedIn: /in/bcmork
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41. @NTXISSA #NTXISSACSC4@NTXISSA #NTXISSACSC4
The Collin College Engineering Department
Collin College Student Chapter of the North Texas ISSA
North Texas ISSA (Information Systems Security Association)
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Thank you