Cryptography and Network Security: Overview potx

Cryptography and Network Security: Overview Raj Jain Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu Audio/Video recordings of this lecture are avail

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Cryptography and

Network Security: Overview

Raj Jain Washington University in Saint Louis

Saint Louis, MO 63130 Jain@cse.wustl.edu

Audio/Video recordings of this lecture are available at:

http://www.cse.wustl.edu/~jain/cse571-11/

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Overview

OSI Security Architecture

Security Attacks

Security Services

5 Security Mechanisms

These slides are based on Lawrie Brown’s slides supplied with William Stalling’s

book “Cryptography and Network Security: Principles and Practice,” 5 Ed, 2011

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Standards Organizations

QO National Institute of Standards & Technology (NIST) http://csrc.nIst.eov/

1 Internet SocIety (TSOC):

Internet Engineering Task Force (IETF), ietf.org

Internet Architecture Board (IAB)

Q International Telecommunication Union

Telecommunication Standardization Sector ITU-T)

http://www.itu.int

QO International Organization for Standardization (ISO)

http://www.iso.org

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Security Components

O Confidentiality: Need access control, Cryptography,

Existence of data

O Integrity: No change, content, source, prevention

mechanisms, detection mechanisms

QO Availability: Denial of service attacks,

O Confidentiality, Integrity and Availability (CIA)

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OSI Security Architecture

OQ ITU-T X.800 “Security Architecture for OSI”

O Defines a systematic way of defining and providing

security requirements

QO Provides a useful, if abstract, overview of concepts

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Aspects of Security

QO Aspects of information security:

> Security attack

> Security mechanism

> Security service

O Note:

> Threat — a potential for violation of security

> Attack — an assault on system security, a deliberate

attempt to

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evade security services

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Passive Attacks

read contents of

message from Bob

to Alice

other comms facility Internet or

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Active Attacks

Darth Capture message from

Bob to Alice; later

replay message to Alice

other comms facility Bob

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Security Services (X.800)

Q Authentication - assurance that communicating entity is the

one claimed

> have both peer-entity & data origin authentication

Q Access Control - prevention of the unauthorized use of a

resource

Q Data Confidentiality —protection of data from unauthorized

disclosure

Q Data Integrity - assurance that data received is as sent by an

authorized entity

QO Non-Repudiation - protection against denial by one of the

parties in a communication

QO Availability — resource accessible/usable

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Security Mechanism

QO Feature designed to detect, prevent, or recover from a

security attack

O However one particular element underlies many of the

security mechanisms in use:

> cryptographic techniques

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Security Mechanisms (X.800)

O Specific security mechanisms:

> Encipherment, digital signatures, access controls,

data integrity, authentication exchange, traffic

padding, routing control, notarization

O Pervasive security mechanisms:

> Trusted functionality, security labels, event

detection, security audit trails, security recovery

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Services and Mechanisms Relationship

Mechanism

Data origin authentication Y Y

Access control Y

Confidentiality Y Y

Traffic flow confidentiality Y Y Y

Data integrity Y Y Y

Nonrepudiation Y Y Y

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Sender

Message

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Model for Network Security

Security-related

transformation

=o

Secret information

message

Trusted third party (e.g., arbiter, distributer

of secret information)

v

Information Channel

Opponent

Algorithm for Security transformation

Secret key generation

Distributed and share secret information

Protocol for sharing secret information

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Recipient

Security-related

transformation °

SL

T 2 “

Secret information

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Model for Network Access Security

Information System

Computing resources (processor, memory, I/O)

Opponent

—software

as

Access Channel Gatekeeper | Software

1 Select appropriate gatekeeper functions to identify

users

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Summary

QO NIST, IETF, ITU-T, [ISO develop standards for network

security

QO CIA represents the 3 key components of security

QO ISO X.800 security architecture specifies security attacks,

services, mechanisms

O Active attacks may modify the transmitted information

O Security services include authentication, access control,

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Lab Homework 2

http://www wireshark.org/download.html Use ftp client to download in binary mode (do not use browser)

http://www.solarwinds.com/products/lansurveyor/

(e.g., CSES71 XPS and CSE571XPC2 in the security lab) to find their

open ports

filter option “IP Address” to capture all traffic to/from this address Open

a browser window and Open www.google.com Stop Wireshark Submit

a screen capture showing the packets seen

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Security URLs

O Center for Education and Research in Information Assurance

and Security,

http://www.cerias.purdue.edu/about/history/coast/archive/

IETF Security area, sec.ietf.org

O Computer and Network Security Reference Index,

http://www vicit.telstra.com.au/info/security.html

O The Cryptography FAQ,

http://www fags.org/faqs/cryptography-faq/

O Tom Dunigan's Security page,

http://www.csm.ornl.gov/%7edunigan/security html

O IEEE Technical Committee on Security and Privacy,

http://www.ieee-security.org/index.html]

UO Computer Security Resource Center, http://csrc.nist.gov/

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Security URLs (Cont)

O Security Focus, http://www.securityfocus.com/

O SANS Institute, hitp://sans.org/

QO Data Protection resource Directory,

http://www.dataprotectionhg.com/cryptographyanddat asecurity/

QO Helger Lipmaa's Cryptology Pointers,

http://www.adastral.ucl.ac.uk/“%7ehelger/crypto/

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Newsgroups and Forums

scl.crypt.research, sci.crypt, sci.crypt.random-numbers

alt.security

comp.security.misc, comp.security.firewalls,

comp.security.announce

comp.risks

comp.virus

O Security and Cryptography Forum,

http://forums.devshed.com/security-and-cryptography-17/

UO Cryptography Forum,

http://www.topix.com/forum/science/cryptography

QO Security Forum, http://www.windowsecurity.com/

O Google groups, http://groups.zoogle.com

OW LinkedIn Groups, http://www.linkedin.com

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