Security technologies

Transforming Lives. Inventing the Future. www.iit.edu

I ELLINOIS T UINS TI TOF TECHNOLOGY

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Security Technologies

Ray TrygstadITM 478/578 Spring 2004Master of Information Technology & Management ProgramCenter for Professional Development

Slides based on Whitman, M. and Mattord, H., Principles of Information Security; Thomson Course Technology 2003

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ILLINOIS INSTITUTE OF TECHNOLOGY

Learning Objectives:Upon completion of this lesson the student should be able to:– Define and identify the various types of firewalls.– Discuss the approaches to firewall

implementation.– Discuss the approaches to dial-up access and

protection.– Identify and describe the two categories of

intrusion detection systems.– Discuss the two strategies behind intrusion

detection systems.

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Learning Objectives:Upon completion of this lesson the student should be able to:– Discuss scanning, analysis tools, and content

filters.– Understand trap and trace technologies.– Discuss the process of encryption and define key

terms.– Identify and discuss common approaches to

cryptography.– Compare and contrast symmetric and asymmetric

encryption.– Discuss various approaches to biometric access

control.

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Introduction Information security: a discipline relying on

the synthesis of people, policy, education, training, awareness, procedures, and technology to improve protection of an organization’s information assets

Technical solutions can maintain– Confidentiality, Integrity & Availability of

information– In each of its three states

• Storage• Transmission• processing

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Physical Design of the SecSDLC

The physical design phase of the SecSDLC is made up of two parts:– security technologies– physical security

Physical design takes the logical design, expressed by the information security blueprint and the contingency planning elements and extends the design to the next level

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Physical Design of the SecSDLC

Ana lyze

Physica l Design:Security Technolog ies

Chapter 8

Physica l Design:Physica l Security

Chapter 9

Logica l Design

Implement

Mainta in

FIG URE 8-1 Ph ysical Design wit hin t he SecSDLCPhysical Design within the SecSDLC

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Physical Design of the SecSDLC The physical design phase encompasses the

selection of technologies and processes to manage risk

At the end of the physical design phase you have:– Selected technologies needed to support the information

security blueprint– Defined what the successful solution for a secured

environment will encompass– Designed physical security measures that support the

technical solutions– Prepared to create project plans in the implementation

phase to follow

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Firewalls A firewall is any device that prevents a

specific type of information from moving between the untrusted network outside and the trusted network inside

There are five recognized generations of firewalls

The firewall may be:– a separate computer system– a service running on an existing router or server– a separate network containing a number of

supporting devices

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First Generation Called packet filtering firewalls Examines every incoming packet header and

selectively filters packets based on– address, packet type, port request, and others

factors The restrictions most commonly

implemented are based on:– IP source and destination address– Direction (inbound or outbound)– TCP or UDP source and destination port-requests

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Packet Filtering FirewallPacket filtering router

used as a first generationfirewall Trusted network

Untrusted Network

FilteredFilteredData PacketsData Packets

UnrestrictedUnrestrictedData PacketsData Packets

BlockedBlockedData PacketsData Packets

FIGURE 8-2 Packet Filtering Firewall

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Second Generation Called application-level firewall or proxy server Often a dedicated computer separate from the

filtering router With this configuration the proxy server, rather

than the Web server, is exposed to the outside world in the DMZ

Additional filtering routers can be implemented behind the proxy server

The primary disadvantage of application-level firewalls is that they are designed for a specific protocol and cannot easily be reconfigured to protect against attacks on protocols for which they are not designed

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Third Generation Called stateful inspection firewalls Keeps track of each network connection

established between internal and external systems using a state table which tracks the state and context of each packet in the conversation by recording which station sent what packet and when

If the stateful firewall receives an incoming packet that it cannot match in its state table, then it defaults to its ACL to determine whether to allow the packet to pass

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Third Generation

The primary disadvantage is the additional processing requirements of managing and verifying packets against the state table which can possibly expose the system to a DoS attack

These firewalls can track connectionless packet traffic such as UDP and remote procedure calls (RPC) traffic

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Fourth Generation A dynamic packet filtering firewall allows only a

particular packet with a particular source, destination, and port address to enter through the firewall

Does this by understanding how the protocol functions, and opening and closing “doors” in the firewall, based on the information contained in the packet header

In this manner, dynamic packet filters are an intermediate form, between traditional static packet filters and application proxies

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Fifth GenerationThe final form of firewall is the kernel

proxy, a specialized form that works under the Windows NT Executive, which is the kernel of Windows NT

It evaluates packets at multiple layers of the protocol stack, by checking security in the kernel as data is passed up and down the stack

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Packet-filtering RoutersMost organizations with an Internet

connection have some form of a router as the interface at the perimeter between the organization’s internal networks and the external service provider

Many of these routers can be configured to filter packets that the organization does not allow into the network

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Packet-filtering RoutersThis is a simple but effective means

to lower the organization’s risk to external attack

The drawback to this type of system includes a lack of auditing and strong authentication

The complexity of the access control lists used to filter the packets can grow and degrade network performance

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Screened-Host Firewall Systems Combine the packet-filtering router with a separate,

dedicated firewall such as an application proxy server

Allows the router to pre-screen packets to minimize the network traffic and load on the internal proxy

Application proxy examines an application layer protocol, such as HTTP, and performs the proxy services

This separate host often referred to as a bastion-host, as it represents a single, rich target for external attacks, and should be very thoroughly secured

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FilteredData

Packets

Screened-Host Firewall

Trusted network

Untrusted Network

UnrestrictedData Packets

BlockedData Packets

FIGURE 8-3 Screened Host Firewall

Bastion-host

Application Level Firewall

Proxy access

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Dual-homed Host Firewalls The bastion-host contains two NICs (network

interface cards) One NIC connected to the external network,

and one connected to the internal network With two NICs all traffic must physically go

through the firewall to move between the internal and external networks

A technology known as network-address translation (NAT) is commonly implemented with this architecture to map from real, valid, external IP addresses to ranges of internal IP addresses that are non-routable

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Dual-homed Host Firewall

Trusted network

Untrusted Network

UnrestrictedData Packets

Blocked ExternalData Packets

FIGURE 8-4 Dual-homed Host Firewall

Dual-homed Host used as a firewall providing Network Address Translation

(NAT)External

filtering router

Internalfiltering router

Public IP Addresses NAT assigned local addresses

Blocked InternalData Packets

Proxy Access

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Screened-Subnet Firewalls (with DMZ)

Consists of two or more internal bastion-hosts, behind a packet-filtering router, with each host protecting the trusted network

The first general model consists of two filtering routers, with one or more dual-homed bastion-host between them

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Screened-Subnet Firewalls (with DMZ)

The second general model involves the connection from the outside or untrusted network going through this path:– Through an external filtering router– Into and then out of a routing firewall to the

separate network segment known as the DMZ Connections into the trusted internal

network are allowed only from the DMZ bastion-host servers

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Screened-Subnet Firewall

Trusted network

Untrusted Network

BlockedData Packets

Proxy access

FIGURE 8-5 Screened Subnet (DMZ)

External filtering router Internal

filtering router

Controlled access

Demilitarized zone (DMZ)

ServersServers

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SOCKS Servers The SOCKS system is a proprietary circuit-level

proxy server that places special SOCKS client-side agents on each workstation

Places the filtering requirements on the individual workstation, rather than on a single point of defense (and thus point of failure)

This frees the entry router of filtering responsibilities, but then requires each workstation to be managed as a firewall detection and protection device

A SOCKS system can require additional support and management resources to configure and manage possibly hundreds of individual clients, versus a single device or set of devices

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Selecting the Right Firewall What type of firewall technology offers the

right balance of protection features and cost for the needs of the organization?

What features are included in the base price? What features are available at extra cost? Are all cost factors known?

How easy is it to set up and configure the firewall? How accessible are staff technicians with the mastery to do it well?

Can the candidate firewall adapt to the growing network in the target organization?

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Configuring and Managing Firewalls

Each firewall device will have its own set of configuration rules that regulate its actions

Simple mistakes can turn the device into a choke point

When security rules conflict with the performance of business, security loses since organizations are much more willing to live with a potential risk than a certain failure

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Firewall Recommended Practices All traffic from the trusted network is allowed out The firewall device is always inaccessible directly

from the public network Allow Simple Mail Transport Protocol (SMTP) data

to pass through your firewall, but insure it is all routed to a well-configured SMTP gateway to filter and route messaging traffic securely

All Internet Control Message Protocol (ICMP) data should be denied

Block telnet (terminal emulation) access to all internal servers from the public networks

When Web services are offered outside the firewall, deny HTTP traffic from reaching your internal networks by using some form of proxy access or DMZ architecture

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Dial-Up Protection While internal network connection via

private networks are now less popular due to the high cost of installation, maintenance, and protection, dial-up connections are still quite common

Unsecured, dial-up access represents a substantial exposure to attack– An attacker who suspects that an organization

has dial-up lines can use a device called a war-dialer to locate the connection points

For the most part, simple username and password schemes are the only means of authentication

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Remote Authentication Dial-in User Service RADIUS system centralizes management of user

authentication by placing the responsibility for authenticating each user in the central RADIUS server

Radius serverRemote access server (RAS)

1. Remote worker dials RAS and submits username and password2. RAS passes username and password to RADIUS server3. RADIUS server approves or rejects request and provides access authorization4. RAS provides access to authorized remote worker

(1) (2)

(3)(4)

Tele-worker

FIGURE 8-6 RADIUS Configuration

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Terminal Access Controller Access Control System

TACACS contains a centralized database, such as RADIUS, and validates the user’s credentials at the TACACS server

There are three versions of TACACS– TACACS– Extended TACACS– TACACS+

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Intrusion Detection Systems (IDSs) IDSs work like burglar alarms IDSs require complex configurations to

provide the level of detection and response desired

An IDS operates as either network-based, when the technology is focused on protecting network information assets, or host-based, when the technology is focused on protecting server or host information assets

IDSs use one of two detection methods, signature-based or statistical anomaly-based

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Intrusion Detection System

External Router

Host IDS: Examines the data in files stored on host and alerts systems administrators to any any changes

Network IDS: Examines packets on network and alerts admin to unusual patterns.

Header0100101011Untrusted

Network

FIGURE 8-7 Intrusion Detection Systems

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Host-based IDSs Resides on a particular computer or server

(known as the host) and monitors activity on that system.

Most work on principle of configuration or change management, in which the systems record the file sizes, locations, and other attributes, and reports when one or more of these attributes changes, when new files are created, and when existing files are deleted.

Can also monitor systems logs for pre-defined events.

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Host-based IDSs Maintains own log files so when hackers

successfully modify a systems log the IDS provides independent verification of the attack Once properly configured, host-IDSs are very reliable.

Managed host-based IDS can monitor multiple computers simultaneously. – Stores a client file on each monitored host – Has that host report back to the master console

(usually located on the sysadmin’s computer)

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Host-based IDS

Host-based IDS

FIGURE 8-8

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Network-based IDSs Works differently than its host-based

counterpart; monitors network traffic When a pre-defined condition occurs, it

responds and notifies the appropriate administrator

Must match known and unknown attack strategies against knowledge base to determine if an attack has occurred

Result in more false positive readings than do host-based IDSs– System is attempting to read into the pattern of

activity on the network to determine what is normal and what is not

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Network-based IDS

Network-based IDS

FIGURE 8-8

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Signature-based IDSs AKA knowledge-based IDS; examines data

traffic looking for something that matches signatures, which are pre-configured, predetermined attack patterns

Problem: signatures must be continually updated as new attack strategies are identified

Attackers who are slow and methodical may slip undetected through the IDS, as actions may not match the signature that includes factors based on duration of the events

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Statistical Anomaly-based IDSsAKA behavior-based IDS Collects data from normal traffic and

establishes a baselineOnce the baseline is established,

periodically samples network activity, based on statistical methods, and compares samples to baseline

If activity is outside baseline parameters (known as a clipping level), IDS notifies administrator

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Statistical Anomaly-based IDSs Advantage: system able to detect new types of

attacks as it looks for abnormal activity of any type

Unfortunately require much more overhead and processing capacity than signature-based versions, as they must constantly attempt to pattern matched activity to the baseline

Also may not detect minor changes to systems variables can generate many false positives

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Scanning And Analysis Tools Used to collect information needed by an

attacker to succeed One of the preparatory parts of an attack is

collection of information about a potential target, a process called footprinting– Organized research of the Internet addresses

owned or controlled by a target organization Attacker uses public Internet data sources to

perform keyword searches to identify the network addresses of the organization

This research augmented with browsing organization’s Web pages

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Scanning And Analysis ToolsNext phase of the pre-attack data

gathering process: fingerprinting Systematic examination of all Internet

addresses of the organization (collected during the footprinting)

Accomplished with tools discussed in the next section, fingerprinting reveals useful information for the anticipated attack

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Scanning And Analysis ToolsScanners, sniffers, and other analysis

tools are invaluable to security administrators; enables them to see what the attacker sees

Can find vulnerabilities in systems, holes in security components, and unsecured aspects of the network – Unfortunately, they cannot detect the

unpredictable behavior of people.

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Scanning And Analysis ToolsMany of these tools have distinct

signatures & some Internet service providers (ISPs) scan for these signatures. – If an ISP discovers someone using

“hacker tools” it can pull access privileges– Best to establish working relationship

with the ISP & notify them of the purpose and extent of the signatures.

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Port Scanners Port scanners fingerprint networks to find

ports and services and other useful information

Why secure open ports? – An open port can be used to send commands to a

computer, gain access to a server, and exert control over a networking device

– The general rule of thumb is to remove from service or secure any port not absolutely necessary for the conduct of business

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Well-known Port NumbersPort numbers Description20 and 21 File Transfer Protocol (FTP)25 Simple Mail Transfer Protocol (SMTP)53 Domain Name Services (DNS)67 and 68 Dynamic Host Configuration Protocol (DHCP)80 Hypertext Transfer Protocol (HTTP)110 Post Office Protocol (POP3)161 Simple Network Management Protocol (SNMP)194 IRC Chat port (used for device sharing)443 HTTP over SSL8080 Used for proxy services

Table 8-2 Well-known Port Numbers

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Source:http://support.gfi.com/manuals/en/lanscan2/analyzingthescanresults.htm

FIGURE 8-11

LANGuardNetwork Scanner

LANguard Network Scanner

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Vulnerability Scanners

Vulnerability scanners are capable of scanning networks for very detailed information

As a class, they identify exposed usernames and groups, show open network shares, expose configuration problems, and other vulnerabilities in servers

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Source:http://www.insecure.org/nmap/images/nmapfe.gif

Nmap Vulnerability ScannerFIGURE 8-12

Nmap Vulnerability Scanner

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Packet Sniffers A network tool that collects copies of

packets from the network and analyzes them

Can be used to eavesdrop on the network traffic

To use a packet sniffer legally, you must be: – on a network that the organization owns – under direct authorization of the owners of the

network – have knowledge and consent of the content

creators (users)

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Source http://www.ethereal.com/docs/user-guide/x885.html

Ethereal Sample ScreenFIGURE 8-13

EtherealSample Screen

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Content Filters

Although technically not a firewall, a content filter is a software filter that allows administrators to restrict accessible content from within a network

The content filtering restricts Web sites with inappropriate content

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Trap and Trace Software designed to entice individuals

illegally perusing the internal areas of a network

Better known as honey pots, they distract the attacker while notifying the administrator

Trace: attempt to determine the identity of someone using unauthorized access– Main purpose: capture system abusers internal to

the network

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Cryptography and EncryptionSophisticated approach to security Many security-related tools use

embedded encryption technologiesEncryption is the process of converting

an original message into a form that is unreadable by unauthorized individuals

The science of encryption, known as cryptology, encompasses cryptography and cryptanalysis

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Encryption Definitions Algorithm: the mathematical formula used to

convert an unencrypted message into an encrypted message.

Cipher: the transformation of the individual components (characters, bytes, or bits) of an unencrypted message into encrypted components.

Ciphertext or cryptogram: the unintelligible encrypted or encoded message resulting from an encryption.

Code: the transformation of the larger components (words or phrases) of an unencrypted message into encrypted components.

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Encryption Definitions Cryptosystem: the set of transformations necessary

to convert an unencrypted message into an encrypted message.

Decipher: to decrypt or convert ciphertext to plaintext.

Encipher: to encrypt or convert plaintext to ciphertext.

Key or cryptovariable: the information used in conjunction with the algorithm to create ciphertext from plaintext.

Keyspace: the entire range of values that can possibly be used to construct an individual key.

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Encryption Definitions Link encryption: a series of encryptions and

decryptions between a number of systems, whereby each node decrypts the message sent to it and then re-encrypts it using different keys and sends it to the next neighbor, until it reaches the final destination.

Plaintext: the original unencrypted message that is encrypted and results from successful decryption.

Steganography: the process of hiding messages in a picture or graphic.

Work factor: the amount of effort (usually in hours) required to perform cryptanalysis on an encoded message.

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Cryptography & Encryption-Based Solutions

Simple forms of encryption are based on two concepts: the block cipher and the exclusive OR operation

With the block cipher method– the message is divided into blocks, i.e., 8 or 16 bit – and then each block is transformed using the

algorithm and key The “exclusive or operation” (XOR) is a

function of Boolean algebra

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Exclusive OR Operations

Bit 1 Bit 2 Exclusive OR result

0 0 0

0 1 1

1 0 1

1 1 0

Exclusive OR OperationsTABLE 8-3

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Encryption Algorithms In encryption the most commonly used

algorithms include two functions: substitution and transposition

In a substitution cipher, you substitute one value for another

This type of substitution is based on a monoalphabetic substitution, since it only uses one alphabet

More advanced substitution ciphers use two or more alphabets, and are referred to as polyalphabetic substitutions

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Encryption Operations Just like the substitution operation, the

transposition cipher is simple to understand but can be complex to decipher if properly used

Unlike the substitution cipher, the transposition cipher (or permutation cipher) simply rearranges the values within a block to create the ciphertext

This can be done at the bit level or at the byte (character) level - transposition ciphers move these bits or bytes to another location in the block, so that bit 1 becomes bit 4, bit 2 becomes bit 7 etc

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Vernam Cipher Also known as the one-time pad, the Vernam

cipher was developed at AT&T and uses a one-use set of characters, the value of which is added to the block of text

The resulting sum is then converted to text When the two are added, if the values

exceed 26, 26 is subtracted from the total (Modulo 26) - the corresponding results are then converted back to text

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Book or Running Key Cipher Another method, made popular by spy

movies, is the use of text in a book as the algorithm to decrypt a message

The key consists of – knowing which book to use– a list of codes representing the page number, line

number, and word number of the plaintext word Dictionaries and thesauruses make the most

popular sources as they guarantee every word needed, although almost any book will suffice

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Symmetric Encryption The same key, also known as a secret key

used to conduct both encryption and decryption of the message

Can be extremely efficient, requiring minimal processing to either encrypt or decrypt the message

Problem: both sender & receiver must own the encryption key– If either copy of the key is compromised, an

intermediate can decrypt and read the messages Challenges: get copy of the key to the

receiver, a process that must be conducted out-of-band to avoid interception

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Symmetric Encryption

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Data Encryption Standard (DES)

Developed in 1977 by IBM Based on the Data Encryption

Algorithm (DEA)Uses a 64-bit block size and a 56-bit

keyWith a 56-bit key, the algorithm has

256 possible keys to choose from (over 72 quadrillion)

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Data Encryption Standard (DES) DES is a federally approved standard for

non classified data RSA put a bounty on the algorithm offering

$10,000 to the team to crack the algorithm Fourteen thousand users collaborated over

the Internet to finally break the encryption On 19 October 1997 at 1325 UTC, the 56 bit

DES algorithm was cracked by a distributed processing system coordinated by a computer in my lab at IIT’s Main Campus

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Triple DES (3DES) Developed as an improvement to DES Uses up to three keys in succession and also

performs three different encryption operations:– 3DES encrypts the message three times with

three different keys, the most secure level of encryption possible with 3DES

In 1998, it took a dedicated computer designed by the Electronic Freedom Frontier (www.eff.org) over 56 hours to crack DES

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Advanced Encryption Standard (AES)The successor to 3DES is Advanced

Encryption Standard (AES), based on the Rijndael Block Cipher, a block cipher with a variable block length and a key length of either128, 192, or 256 bits

It would take the same computer approximately 4,698,864 quintillion years to crack AES

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Asymmetric Encryption Best known as public key encryption Uses two different keys Either key can be used to encrypt or decrypt

the message, however, if Key A is used to encrypt the message, only Key B can decrypt, and if Key B is used to encrypt a message, only Key A can decrypt it.

Public key is stored in a public location, where anyone can use it

Private key is a secret known only to the owner of the key pair

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Using Public Keys

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Digital Signatures An interesting thing happens when the

asymmetric process is reversed, that is the private key is used to encrypt a short message

The public key can be used to decrypt it, and the fact that the message was sent by the organization that owns the private key cannot be refuted

This is known as nonrepudiation, which is the foundation of digital signatures

Digital Signatures are encrypted messages that are independently verified by a central facility (registry) as authentic

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RSA One of the most popular public key

cryptosystems Stands for Rivest-Shamir-Aldeman, its

developers First public key encryption algorithm

developed and published for commercial use Part of Web browsers from both Microsoft

and Netscape 56 bit version is not secure; 128 bit version is

acceptable

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PKI or Public Key Infrastructure Public Key Infrastructure is the entire set of

hardware, software, and cryptosystems necessary to implement public key encryption

PKI systems are based on public-key cryptosystems and include digital certificates and certificate authorities (CAs) and can:– Issue digital certificates– Issue crypto keys– Provide tools to use crypto to secure information– Provide verification and return of certificates

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PKI Benefits

PKI protects information assets in several ways: – Authentication– Integrity– Privacy– Authorization– Nonrepudiation

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Digital Certificates & Certificate Authorities

A digital certificate is an electronic document, similar to a digital signature, attached to a file certifying that this file is from the organization it claims to be from and has not been modified from the original format

A Certificate Authority is an agency that manages the issuance of certificates and serves as the electronic notary public to verify their worth and integrity

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Hybrid Systems In practice, pure asymmetric key encryption not

widely used except in the area of certificates More often used in conjunction with symmetric

key encryption creating a hybrid system Use the Diffie-Hellman Key Exchange method

that uses asymmetric techniques to exchange symmetric keys to enable efficient, secure communications based on symmetric keys

Diffie-Hellman provided the foundation for subsequent developments in public key encryption

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Hybrid Encryption Example

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Securing E-mail Encryption cryptosystems have been

adapted to inject some degree of security into e-mail:– S/MIME builds on the Multipurpose Internet

Mail Extensions (MIME) encoding format by adding encryption and authentication

– Privacy Enhanced Mail (PEM) was proposed by the Internet Engineering Task Force (IETF) as a standard to function with the public key cryptosystems

– PEM uses 3DES symmetric key encryption and RSA for key exchanges and digital signatures

– Pretty Good Privacy (PGP), developed by Phil Zimmerman, uses the IDEA Cipher along with RSA for key exchange

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Securing the Web

Secure Electronic Transactions (SET) Secure Socket Layer (SSL)Secure Hypertext Transfer Protocol

(SHTTP) Secure Shell (SSH) IPSec

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IPSec IP Security (IPSec) is the cryptographic

authentication and encryption product of the IETF’s IP Protocol Security Working Group

Defined in RFC 1825, 1826, and 1827 Used to create Virtual Private Networks

(VPNs) and is an open framework for security development within the TCP/IP family of protocol standards

Combines several different cryptosystem elements and includes: – the IP Security Protocol itself– the Internet Key Exchange

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IPSec Operations IPSec works in two modes of operation:

– In transport mode only the IP data is encrypted, not the IP headers themselves

– In tunnel mode, the entire IP packet is encrypted and is then placed as the payload in another IP packet

The implementation of these technologies is very popular through a process known as Virtual Private Networks (VPNs)

In the most common implementation, a VPN allows a user to turn the Internet into a private network between points on the public network

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Kerberos Scenario: Initial Login

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Kerberos Scenario: Request for Services

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Sesame To solve some of the problems associated

with Kerberos, a new project, the Secure European System for Applications in a Multivendor Environment (SESAME), was developed as a European research and development project, partly funded by the European Commission

SESAME is similar in part to Kerberos in that the user is first authenticated to an authentication server to receive a token

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Access Control Devices To insure secure operation, access control needs

strong authentication (two-factor authentication) Consist of the user’s personal password or

passphrase but requires at least one other factor to represent strong authentication

Frequently a physical device is used for the second factor

When considering access control you address: – What you know– What you have– Who you are– What you produce

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What You Are - Biometrics Most of the technologies that scan human

characteristics convert these images to some form of minutiae

Minutiae are unique points of reference that are digitized and stored in an encrypted format

Each subsequent scan is also digitized and then compared with the encoded value to determine if users are who they claim to be

The problem is that some human characteristics can change over time, due to normal development, injury, or illness

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Voice recognition

Signature recognitionHandgeometryHand and palm

print

Fingerprint Irisrecognition

RetinalRecognition

Facialgeometry

Recognition Characteristics

FIGURE 8-20Recognition Characteristics

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Effectiveness of Biometrics

Biometric technologies are evaluated on three basic criteria:– False Reject Rate– False Accept Rate– Crossover Error Rate

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False Reject Rate (FRR)The percentage or value associated

with the rate at which authentic users are denied or prevented access to authorized areas, as a result of a failure in the biometric device

Type I errorProbably of the least concern to

security

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False Accept Rate (FAR)

The percentage or value associated with the rate at which fraudulent or non-users are allowed access to systems or areas, as a result of a failure in the biometric device

Type II errorThis type of error is unacceptable to

security, as it represents a clear breach

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Crossover Error Rate (CER)The crossover error rate is the point

at which the number of false rejections equals the false acceptances, also known as the equal error rate

It is possibly the most common and important overall measure of the accuracy of a biometric system

The optimal setting is somewhere near the equal error rate or CER

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Acceptability of Biometrics

While the use of one authentication area is necessary to access the system, the more devices used the better

To obtain strong authentication, the systems must use two or more authentication areas

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The End…

Questions?