Josh
January 15, 2014
200

Crypto For Makers

Presentation given to SparkFun Electronics on crypto, the BeagleBone Black and Submarines.

January 15, 2014

Transcript

1. Crypto for Makers
Primers on Crypto, BeagleBone Black, and Submarines
Josh Datko
Cryptotronix, LLC
January 15, 2014
Josh Datko Crypto for Makers January 15, 2014 1 / 34

2. 1 Crypto Primer
2 BeagleBone Capes
3 CryptoCape
4 Crypto Projects
5 Export Controls
6 Going Further
7 Submarines
Josh Datko Crypto for Makers January 15, 2014 2 / 34

3. Security
Credit: https://xkcd.com/538/
Josh Datko Crypto for Makers January 15, 2014 3 / 34

4. Code Talkers
Credit: https://xkcd.com/257/
Josh Datko Crypto for Makers January 15, 2014 4 / 34

5. PGP
Credit: https://xkcd.com/1181/
Josh Datko Crypto for Makers January 15, 2014 5 / 34

6. Meet Alice and Bob
Most cryptography examples uses Alice and Bob as two people who want
to communicate securely.
Basic Encryption
Given a message, m, an encryption algorithm, E, and a key Ke,
produce a ciphertext, c, such that: c = E(Ke, m)
Meet Eve. Eve is an eavesdropper. If Eve knows only c, she can’t recover
m without Ke.
Basic Decryption
Given a ciphertext, c, decryption algorithm, D, and a key Ke, produce
a message, m, such that: m = D(Ke, c)
Josh Datko Crypto for Makers January 15, 2014 6 / 34

7. Symmetric Key Algorithms
Credit: https://en.wikipedia.org/wiki/File:Crypto.png
Josh Datko Crypto for Makers January 15, 2014 7 / 34

8. List of common Symmetric Key Algorithms
Data Encryption Standard (DES)
3DES
RC4
Twoﬁsh
Josh Datko Crypto for Makers January 15, 2014 8 / 34

9. Key Distribution Problems
en.wikipedia.org/wiki/File:Kriegsmarine_Enigma.png
en.wikipedia.org/wiki/File:Kenngruppenheft.jpg
Problem
How do you ensure ev-
erybody is using the
same key???
Josh Datko Crypto for Makers January 15, 2014 9 / 34

10. Asymmetric Cryptography
https://en.wikipedia.org/wiki/File:Public-key-crypto-1.svg
RSA is the most popular public key encryption scheme, which is based on
the prime-number factorization problem.
Josh Datko Crypto for Makers January 15, 2014 10 / 34

11. Elliptical Curve Cryptography (ECC)
ECC is generally faster and more eﬃcient than RSA. However, there are a
lot important technical details to consider.
Josh Datko Crypto for Makers January 15, 2014 11 / 34

12. Hash Functions
A cryptographic hash function has the following properties:
One-way. Given a function, h, it’s easy to ﬁnd h(m), but not possible
calculate m given x where h(m) = x.
Collision Resistant. For a message m1, it is diﬃcult to ﬁnd another
message m2, such that h(m1) = h(m2)
The mapping for all possible inputs to the set of outputs should be
random
https://en.wikipedia.org/wiki/File:Cryptographic_Hash_Function.svg
Josh Datko Crypto for Makers January 15, 2014 12 / 34

13. Bitcoin
Digital cash.
Who is Satoshi Nakamoto???
P2P Currency.
Bitcoin is not anonymous!!!
Josh Datko Crypto for Makers January 15, 2014 13 / 34

14. BeagleBone Black
1GHz TI Sitara AM3359
ARM Cortex A8
512 MB DDR3L @ 400
MHz
2 GB on-board eMMC,
MicroSD
GPIO 65 Pins!, PRU,
Crypto Accelerator!
Uses actual Debian armhf
Raspian is not Debian
https:
//wiki.debian.org/
RaspberryPi
3,000 BBBs a week. Credit: BeagleBoard SRM
Josh Datko Crypto for Makers January 15, 2014 14 / 34

15. How to Build a BBB Cape
2 Format EEPROM according to the SRM
4 Build a device tree ﬁle
Josh Datko Crypto for Makers January 15, 2014 15 / 34

16. EEPROM Schematic
Josh Datko Crypto for Makers January 15, 2014 16 / 34

17. EEPROM Data
EEPROM Revision (A0, A1, etc. . . )
32 byte board name
4 byte version (up to manufacturer)
16 Byte part number
12 Byte Serial number. WWYY&&&&nnnn
An open source EEPROM generator exists:
https://github.com/picoflamingo/BBCape_EEPROM
Important
Board name and version should match your DTS ﬁle!
Josh Datko Crypto for Makers January 15, 2014 17 / 34

Credit: BBB SRM and BeagleBoard.org
Watch this video!
Josh Datko Crypto for Makers January 15, 2014 18 / 34

19. Watch out for Boot Pins
Credit: BBB SRM and BeagleBoard.org
Josh Datko Crypto for Makers January 15, 2014 19 / 34

20. Device Tree
fragment@0 {
t a r g e t = <&am33xx pinmux >;
o v e r l a y {
p i n c t r l u a r t 5 : p i n c t r l u a r t 5 p i n s {
p i n c t r l −s i n g l e , pins = <
0x070 0x26 /∗ P9 11 = GPIO0 30 =
GPMC WAIT0 , MODE6 ∗/
0x074 0x06 /∗ P9 13 = GPIO0 31 =
GPMC WPN, MODE6 ∗/
Where did those numbers come from???
https://github.com/derekmolloy/boneDeviceTree/tree/
master/docs
Josh Datko Crypto for Makers January 15, 2014 20 / 34

Decoding Byte 1
Memory oﬀset from 0x800 for the processor
Decoding Byte 2
Bit 6: Slew Control: 0 = Fast, 1 = Slow
Bit 5: Receiver Active: 0 = Disable, 1 = Enable
Bit 4: Pullup / Down: 0 = Pulldown, 1 = Pullup
Bit 3: Pull Enable: 0 = Enable, 1 = Disabled
Bits 2,1,0: Mux Mode
0x070 0x26
0b0100110 = Fast, Receive, Pulldown, Mode 6 = uart4 rxd mux2
0x074 0x06
0b0000110 = Fast, Transmit, Pulldown, Mode 6 = uart4 txd mux2
Josh Datko Crypto for Makers January 15, 2014 21 / 34

Compile the device tree. https:
//raw.github.com/RobertCNelson/tools/master/pkgs/dtc.sh
Move over to ﬁrmware directory.
Activate by echoing the name of the Cape to capemgr.
Josh Datko Crypto for Makers January 15, 2014 22 / 34

23. Example: Flashing ATMega328p from BBB
http://datko.net/2013/11/11/bbb_atmega328p/
Josh Datko Crypto for Makers January 15, 2014 23 / 34

24. Cryptotronix
Things not to do before months before you have your ﬁrst child:
Start talking about Open source Crypto Hardware.
Quit Job.
Start company.
Goal
Get open source hardware crypto tools in the hands of makers.
Josh Datko Crypto for Makers January 15, 2014 24 / 34

25. CryptoCape
Crypto ICs (TPM, ECC,
SHA256)
Secure Boot
Hardware protected
keys
Key isolation vs
acceleration
RTC w/ Battery
AtMega328P for User
Crypto Libs
Josh Datko Crypto for Makers January 15, 2014 25 / 34

26. I can haz Crypto?
Tor Relay.
VPN endpoint.
Squid Proxy.
Key Store (wallet).
If it talks on the Internet:
weather station, GPS
location, vital signs.
AVR projects are harder:
IC code is proprietary.
NaCl (crypto lib) looks
good.
Might need two AVRs. . .
Josh Datko Crypto for Makers January 15, 2014 26 / 34

27. Export Controlled
Most crypto hardware is export controlled.
BBB is ECCN: 5A002A1. (Onboard Crypto Accelerator).
Publicly available software generally has an exception
Posting encryption source code and corresponding object code on the
Internet (e.g., FTP or World Wide Web site) where it may be downloaded
by anyone neither establishes “knowledge” of a prohibited export or
reexport for purposes of this paragraph, nor triggers any red ﬂags
necessitating the aﬃrmative duty to inquire
http://www.bis.doc.gov/index.php/policy-guidance/
encryption/identifying-encryption-items
Josh Datko Crypto for Makers January 15, 2014 27 / 34

28. Legal Hacks
Credit: https://xkcd.com/504/
Josh Datko Crypto for Makers January 15, 2014 28 / 34

29. Going Further
Hopefully at Hope X!
Hardware Bitcoin Wallet @30c3:
Hardware Attacks, Advanced ARM Exploitation @ 30c3:
Tutorial on BBB Cape EEPROM.
https://github.com/jbdatko/eeprom_tutorial
Jason Kridner on Device Tree
master/test-capemgr
Josh Datko Crypto for Makers January 15, 2014 29 / 34

30. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 30 / 34

31. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 31 / 34

32. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 32 / 34

33. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 33 / 34

34. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 34 / 34

35. Submarines
Credit: Oﬃcial U.S. Navy Photo
Josh Datko Crypto for Makers January 15, 2014 35 / 34