State University of Telecommunications
Line cipher demonstration for
educational purposes
P.M. Tutunnick, paul_3@front.ru
Advisor: D.V. Kushnir
• Cryptology basics:
Outline
– Subject and main directions
– Binary functions
• The overview of “Virtual University” complex creation history
• Main principles of PC-based laboratory exercise
• “LogiCon” experimentation tool introduction:
– Nature and general purpose
– Main features list
– Engine functionality basics
– Interface capablities
• Application example:
– “Exploration of Line-Recurrent Register” exercise
– Key generator projects contest
• Complex adapation posiblities
• Alternative use directions
• Progress perspectives
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Cryptology Subject
Science about safety of communications
Cryptography
Cryptanalysis
The science studying principles,
methods and means of
transformation of the information
for its protection against
unauthorized access and
distortion.
The science studying principles
of possible cryptoatacks, and
measuring defensive potential of
cryptosystems.
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Cryptography directions
It provides:
• Secrecy of stored private information
• Safety of messaging
• Users autentification
• Security of algorithms
• Passwords & keys management
Objects to protect :
• Encryption and decryption algorithm
• Transmitting channels
• Encryption details
Types of important information,
that needs to be protected:
• State secret
• Military secret
• Commercial secret
• Jurisprudential Secret
• Medical secret
• etc.
• User co-ordinates
• Fact of encrypted transmittion
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Tipical Cryptosystem Model
Simple Ciphers:
• Replacement ciphers
(Lisandr, “Scitala”)
• Switching ciphers
(“Caesar cipher”)
Main Types of Attacks :
• Statistical (“linguoanalysis”) attac
• Algorithm (“exploit”) attack
• Chosen content (“user”) attack
• Block-revealing (“vocabulary”) attack
• Power (“all-key”) attack
• Destructive (“heating”) attack
• etc.
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Binary Functions
y=F(x1,x2,..xn)
Decimal (Multiplexing)
1
2
3
4
1
1
2
3
4
2
2
4
6
8
3
3
6
9
12
4
4
8
12
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Binary (OR operation)
Binary Basis
“NOT”
“AND”
0
1
0
0
1
1
1
1
3D Basis
“OR”
x1
y
x1
x2
y
x1
x2
y
0
1
0
0
0
0
0
0
1
0
0
1
0
0
1
1
1
0
0
1
0
1
1
1
1
1
1
1
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x1
x2
y
0
0
0
0
1
1
1
0
1
1
1
0
Basis Functions Combining
Example:
“XOR” Operator
Y  X1  X 2
X1  X 2  X 2  X1
P( X 2  1)  50%  P(Y  1 | X 2  1)  50%
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“Virtual university” project complex
• Started: 1993
• Developed by: teachers and students of SUT ITTERC
• Meant to: assist the educational courses by interactive
demonstration of it’s subjects and systematyse already
existing thematical computing researches
• Now allows to:
– Provide high-quality visual & interactive representings of
described physical & logical processes
– Fully automatyse technicaly aspects of educational
processes
– Stimulate new researches by integrating it in earlier
application packages
– Complete practical tasks remotely via internet
– Use virtual laboratories for performing topical
experiments of any kind without any additional
equipment
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Subjects of University, in which project components
are employed:
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Cryptography
Steganography
Programming on C Language
Programming on Assembler
Language
• High Level Programming
• Computing Support of
Engeneering
• ElectroCommunications Theory
• SchemoTechnics Basics
• Digital Processing of Signals
• Military practice
Most of program complexes developed by ITTERC are
integrated in the common database system that provides user
access, basing on a Smart-Card technology, and contains
student practice real-time statistics.
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PC-based practice program properties:
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Educational utility
Clear work plan
Interactive elucidative texts
Not too formal and easy to perform
Acceptable visualization quality
Unified interface functionality
Wide experimental capabilities
Controling and score-counting tools
Integrated client-server system
Modification abilities
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Virtual Logical Models Constructor Utility
aka LogiCon
- Multipurposal educational
desighning toolset package, that
allows to create, redact and
analyse fully operational logical
schemes of different sorts.
- Was developed in 2004 for
demonstration of cryptography
basic algorithms.
- Upgraded to provide experience of exploring and development of
abstract logic schemes, allowing to applicate it more effectively and
widely.
- Is currently bypassing final adaptation and tests before getting into
exploitation.
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LogiCon Project main features list
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Flexible logical functionality
User-friendly interface
Drag’n’drpop-based workspase
Rich set of pre-programed logical elements
Nearly unlimited number of construction blocks
Blocks flexible tuning ability
Multi-level logic desighn
File-level exchange
Built-in script sublanguage
Abitity to model occasionaly events
Statistic analiser tools
Interactive guiding informer
Smart result-checking system
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LogiCon Engine functionality basics: “block”
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Primary construction element
Low-level defined visual object
Provides inner data processing
• Input/Output
• Registers
• Functions
• Custom Operators
Each kind of element is supported with a individual settings system
with a simple access by a pop-up menu, allowing to change block
options swiftly without replacing it.
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LogiCon Engine functionality basics: “link”
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Single-sided connection between blocks
Defined as a block logical property
Delivers the binary calculation results
User-established links define a scheme graph virtual
matrix, allowing it to perform logical operations.
LogiCon Engine functionality basics: “phase”
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Standart, constantive state of a scheme
Untill switched all digital values remain unchanged
Proceeding to the next phase allows to spectate sceme
operating step-by-step and to receive the intermediate
results of process.
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Logicon Interface Components
System Menu
Stand-Alone
Component
Availible
Components
Zoom-In/Out
Switch to
Next/Previous Phase
Desighn Space
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Block Ciphering
Stream (Line) Ciphering
Joining Algorithm
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Simple stream cipher algorithm
Encryption
Decryption
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LogiCon representation
Encryption
Decryption
Transmission
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Linear recurrent register shift algorithm
n
B0,2=F(B2,1,B7,1)
T=2n-1
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Modified (switching) key generator
T=T1.T2.T3
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Thank you for attention!
Спасибо за внимание!
LogiCon
paul_3@front.ru
www.uicitt-sut.spb.ru
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