Transcript Cryptography - University of Tulsa

Cryptography Evolution
Joshua Poplawski
4/18/2013
Which of these is an example of
cryptography?
A. P S A N A N K N O Y M O P G O N N K D O
B. CODE-187
C.
Don’t get confused
• Code: Using letters, figures and/or symbols to
represent a message
• CODE 187
• Steganography: Art and practice of concealing
a message
• http://www.youtube.com/watch?v=_8wAUdK
F9Yk
Cipher
Pt Shis
PSAN
A NAN
A
is N aK NNOYMOP
secret
O Y M O PGONNKDO
message
GONNKDO
• Replacing regular letters numbers or symbols
with others
WAR
• Romans Used Ciphers
• 1917 -- US Army created the Cipher Bureau
with in the Military Intelligence Division
• 1930 – US Army Signal Security Agency (SSA)
• 1949 – Armed Forces Security Agency (AFSA)
• 1952 – National Security Agency (NSA)
Cryptography = Munitions?!
• Until 1996 encryption fell under International
Traffic in Arms Regulations (ITAR)
– classified encryption as arms
– prohibiting export of encryption from the US
without a license.
• In 1996 fell under Export Administration
Regulations (EAR)
• EAR amended some provisions in 2010
Cryptography in the Commercial realm
• Growing use of wire money transfers put
pressure on export restrictions
• Data Encryption Standard 1975
• The rise of Personal Computers and The
Internet
• Development of electronic commerce
Where is encryption used?
• EVERY WHERE!
• You need encryption any time you are storing,
sharing or transmitting “sensitive information”
Fundamental Concepts
• Symmetric
– One key to encrypt and decrypt
• Asymmetric
– Two keys, one to encrypt and one to decrypt
– Generally used to share symmetric keys.
Fundamental Concepts
• Confusion
– Obscuring the relationship between plaintext and
cipher text
– Substitution
• Polyalphabetic cipher
Fundamental Concepts
• Diffusion
– Dissipates redundancy of plaintext
– Transposition/permutation
Fundamental Concepts
• Block Cipher
– Encrypts a group of bits at a time as one block
– Can be used in multiple ways
– Have to wait for whole block to encrypt before
you send block
• Stream Cipher
– Convert plain text to cipher text one bit at a time
– Can send bit by bit, good for streaming Audio or
Video
Strong Modern Cipher Algorithms
• Rijendael Cipher (AES)
• Serpent
• Twofish
Algorithm
Created By
Key Size
Block Size
Algorithm Rounds
Structure
Substitution- 10, 12 or
Permutation
14
Network
Rijndael
Joan Daemen & 128 bits, 192
Vincent Rijmen bits, 256 bits
in 1998
128 Bits
Twofish
Bruce Schneier 128 bits, 192
in 1993
bits or 256
bits
Bruce Schneier 32-448 bit in
in 1993
steps of 8
bits. 128 bits
by default
Ron Rivest in
Variable
1987
128 bits
Feistel
Network
64 bits
Variable
Blowfish
RC4
RC2
Ron Rivest in
1987
TripleDES
IBM in 1978
DES
IBM in 1975
8-128 bits in
steps of 8
bits. 64 bits
by default
112 bits or
168 bits
56 bits
64 bits
64 bits
64 bits
Cracked? Existing Cracks
No
Side channel
attacks
16
No
Feistel
Network
16
No
Truncated
differential
cryptanalysis
Second-order
differential attack
Stream
Unknown
Yes
Distinguishers
based on weak
key schedule
Source-Heavy 16 Mixing
Feistel
2 Mashing
Network
Yes
Related-Key attack
48
No
16
Yes
Theoretically
possible
Brute force attack,
differential
crypanalysis, linear
cryptanalysis,
Davies' attack
Feistel
Network
Feistel
Network
Reference List
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http://www.colemer.org/Common_Police_Codes.htm
http://www.youtube.com/watch?v=_8wAUdKF9Yk
http://www.nsa.gov/public_info/_files/cryptologic_spectrum/early_history_nsa.pdf
http://www.nsa.gov/about/cryptologic_heritage/vigilance_park/origins_of_asa.shtml
http://en.wikipedia.org/wiki/National_Security_Agency
http://ncoic.com/nsa.htm
http://en.wikipedia.org/wiki/Export_of_cryptography_in_the_United_States
http://www.gibsondunn.com/publications/Documents/WebcastSlides-EncryptionExportControls02-21-2012.pdf
http://www.bis.doc.gov/encryption/
http://www.gibsondunn.com/publications/Documents/WebcastSlides-EncryptionExportControls02-21-2012.pdf
http://encryption_policies.tripod.com/us/baker_060100_regulation.htm
http://arstechnica.com/business/2012/02/from-encryption-to-darknets-as-governments-snoopactivists-fight-back/
http://www.bis.doc.gov/encryption/question6sub_2.htm
http://www.bis.doc.gov/encryption/question6sub_3.htm
http://www.bis.doc.gov/encryption/question6sub_4.htm
http://www.bis.doc.gov/encryption/enc_faqs.htm
http://packetlife.net/blog/2010/nov/23/symmetric-asymmetric-encryption-hashing/
http://www.infosectoday.com/Articles/Intro_to_Cryptography/CryptoFig04.jpg
http://www.kellermansoftware.com/t-ArticleStrongestAlgo.aspx
Reference List
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Pfleeger, Charles. Pfleeger, Shari; Security in Computing; 3rd Edition; Prentice Hall PTR; 2003;
ISBN: 0-13-035548-8
Schneier, Bruce; Applied Cryptography Protocols, Algorithms, and Source Code in C; John
Wiley & Sons, Inc.; 1994; ISBN: 0-471-59756-2
http://en.wikipedia.org/wiki/Serpent_(cipher)
http://en.wikipedia.org/wiki/Advanced_Encryption_Standard_process
http://en.wikipedia.org/wiki/Rijndael
short answer exam question
• What developments lead to the private and
commercial use of encryption?