Group- Group -per per- -Region Allocation Region Allocation - - PDF document

group group per per region allocation region allocation
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Group- Group -per per- -Region Allocation Region Allocation - - PDF document

Group- Group -per per- -Region Allocation Region Allocation Region Bounds Region Bounds An entity has to change its target An entity has to change its target Partition the world into regions Partition the world into regions


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SLIDE 1

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Group Group-

  • per

per-

  • Region Allocation

Region Allocation

Partition the world into regions

Partition the world into regions and assign each region to a and assign each region to a multicast group multicast group

  • An entity transmits to groups

An entity transmits to groups corresponding to the region(s) that corresponding to the region(s) that cover its location cover its location

  • The entity subscribes to groups

The entity subscribes to groups corresponding to interesting corresponding to interesting regions regions

  • Entities have limited

Entities have limited control over control over their nimbus but less their nimbus but less control over control over their focus their focus

Region Bounds Region Bounds

  • An entity has to change its target

An entity has to change its target group(s) throughout its lifetime group(s) throughout its lifetime

  • track the bounds of the current

track the bounds of the current region region

  • learn the multicast address of a

learn the multicast address of a new region new region

  • boundaries and addresses

boundaries and addresses assigned to the regions are often assigned to the regions are often static static

  • In grid

In grid-

  • based region assignment

based region assignment there are many points at which there are many points at which multiple grids meet multiple grids meet

  • Near these corners an entity has to

Near these corners an entity has to subscribe to several groups subscribe to several groups

Environment vs. Regular Environment vs. Regular Tessellation Tessellation Hybrid Multicast Aggregation Hybrid Multicast Aggregation

  • Balance between

Balance between fine fine-

  • grained

grained data partitioning data partitioning and multicast grouping and multicast grouping

  • Three

Three-

  • tiered

tiered interest interest management system: management system:

1.

  • 1. Group

Group-

  • per

per-

  • region

region scheme scheme segments data based on segments data based on location location

2.

  • 2. Group

Group-

  • per

per-

  • entity

entity scheme scheme allows receiver to select allows receiver to select individual entities individual entities

3.

  • 3. Area

Area-

  • of
  • f-
  • interest

interest filter filter subscriptions subscriptions

Projections Projections

Location Location Type Type Cars between Cars between (85,70) and (85,70) and (110,85) (110,85) Tanks between Tanks between (10,25) and (10,25) and (30,40) (30,40) Composed Projection Composed Projection

  • Projection aggregation

Projection aggregation server server

  • collect data for a projection

collect data for a projection

  • transmit aggregated packets

transmit aggregated packets (projection aggregations) (projection aggregations)

  • Projection composition

Projection composition

  • merge the interest

merge the interest specifications of the specifications of the component projections component projections

Compensating Resource Limitations: Recapitulation Compensating Resource Limitations: Recapitulation

  • IPE: Resources =

IPE: Resources = M M × × H H × × B B × × T T × × P P

  • Aspects:

Aspects:

  • consistency and responsiveness

consistency and responsiveness

  • scalability

scalability

  • Protocol optimization

Protocol optimization

  • Dead reckoning

Dead reckoning

  • Local perception filters

Local perception filters

  • Synchronized simulation

Synchronized simulation

  • Area

Area-

  • of
  • f-
  • interest filtering

interest filtering

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SLIDE 2

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§10 Cheating Prevention §10 Cheating Prevention

  • traditional cheating in computer games

traditional cheating in computer games

  • cracking the copy protection

cracking the copy protection

  • fiddling with the binaries: boosters, trainers, etc.

fiddling with the binaries: boosters, trainers, etc.

  • here, the focus is on multiplayer online games

here, the focus is on multiplayer online games

  • exploiting technical advantages

exploiting technical advantages

  • exploiting social advantages

exploiting social advantages

  • cheaters’ motivations

cheaters’ motivations

  • vandalism and dominance

vandalism and dominance

  • peer prestige

peer prestige

  • greed

greed

The goals of cheating prevention The goals of cheating prevention

  • protect the sensitive information

protect the sensitive information

  • cracking passwords

cracking passwords

  • pretending to be an administrator

pretending to be an administrator

  • provide a fair playing field

provide a fair playing field

  • tampering the network traffic

tampering the network traffic

  • colluding with other players

colluding with other players

  • uphold a sense of justice inside

uphold a sense of justice inside the game world the game world

  • abusing beginners

abusing beginners

  • gangs

gangs

Network Security Network Security

  • Military

Military

  • private

private networks networks → → no problem no problem

  • Business, industry, e

Business, industry, e-

  • commerce,…

commerce,…

  • ‘traditional’

‘traditional’ security problems security problems

  • Entertainment industry

Entertainment industry

  • multiplayer computer games, online games

multiplayer computer games, online games

  • specialized

specialized problems problems

Taxonomy Taxonomy of Online Cheating

  • f Online Cheating 1 (4)

1 (4)

  • Cheating by compromising

Cheating by compromising passwords passwords

  • dictionary attacks

dictionary attacks

  • Cheating by social engineering

Cheating by social engineering

  • password scammers

password scammers

  • Cheating

Cheating by denying service from peer players by denying service from peer players

  • denial

denial-

  • of
  • f-
  • service

service ( (DoS) attack DoS) attack

  • clog

clog the opponent’s the opponent’s network connection network connection

Taxonomy Taxonomy of Online Cheating

  • f Online Cheating 2 (4)

2 (4)

  • Cheating

Cheating by tampering with by tampering with the network traffic the network traffic

  • reflex augmentation

reflex augmentation

  • packet interception

packet interception

  • look

look-

  • ahead cheating

ahead cheating

  • packet replay attack

packet replay attack

  • Cheating with authoritative clients

Cheating with authoritative clients

  • receivers accept commands blindly

receivers accept commands blindly

  • requests instead of commands

requests instead of commands

  • checksums from the game state

checksums from the game state

fire fire fire fire rotate rotate

Taxonomy Taxonomy of Online Cheating

  • f Online Cheating 3 (4)

3 (4)

  • Cheating due to illicit information

Cheating due to illicit information

  • access to replicated, hidden game data

access to replicated, hidden game data

  • compromised software or data

compromised software or data

  • Cheating related with internal misuse

Cheating related with internal misuse

  • privileges

privileges of system administrators

  • f system administrators
  • logging critical operations into

logging critical operations into CD CD-

  • ROMs

ROMs

  • Cheating by exploiting a bug or design flaw

Cheating by exploiting a bug or design flaw

  • repair the observed defects with patches

repair the observed defects with patches

  • limit the original functionality to avoid the defects

limit the original functionality to avoid the defects

  • good software design in the first place!

good software design in the first place!

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SLIDE 3

3

Taxonomy Taxonomy of Online

  • f Online Cheating 4 (4)

Cheating 4 (4)

  • Cheating by

Cheating by collusion collusion

  • two or more players play together without

two or more players play together without informing the other participants informing the other participants

  • ne cheater participates as two or more players
  • ne cheater participates as two or more players
  • Cheating related

Cheating related to to virtual assets virtual assets

  • demand

demand ⇒ ⇒ supply supply ⇒ ⇒ market market ⇒ ⇒ money flow money flow ⇒ ⇒ cheating cheating

  • Cheating by offending other players

Cheating by offending other players

  • acting against the ‘spirit’ of the game

acting against the ‘spirit’ of the game

Breaking the control protocol: Breaking the control protocol: Maladies & remedies Maladies & remedies

  • malady

malady: : change data in the messages and observe effects change data in the messages and observe effects

  • remedy

remedy: : checksums (MD5 algorithm) checksums (MD5 algorithm)

  • malady

malady: : reverse engineer the checksum algorithm reverse engineer the checksum algorithm

  • remedy

remedy: : encrypt the messages encrypt the messages

  • malady

malady: : attack with packet replay attack with packet replay

  • remedy

remedy: : add state information (pseudo add state information (pseudo-

  • random numbers)

random numbers)

  • malady

malady: : analyse messages based on their sizes analyse messages based on their sizes

  • remedy

remedy: : modify messages and add a variable amount of junk data to modify messages and add a variable amount of junk data to messages messages

MD5 algorithm MD5 algorithm

  • message digest = a constant length ‘fingerprint’ of

message digest = a constant length ‘fingerprint’ of the message the message

  • no one should be able to produce

no one should be able to produce

  • two messages having the same message digest

two messages having the same message digest

  • the original message from a given message digest

the original message from a given message digest

  • R. L. Rivest: MD5 algorithm
  • R. L. Rivest: MD5 algorithm
  • produces a 128

produces a 128-

  • bit message digest from

bit message digest from an arbitrary length message an arbitrary length message

  • collision attack: different messages with the same

collision attack: different messages with the same fingerprint fingerprint

  • finding collisions is (now even technically!) possible

finding collisions is (now even technically!) possible

  • what is the future of message digest algorithms?

what is the future of message digest algorithms?

Illicit information Illicit information

  • access to replicated, hidden game data

access to replicated, hidden game data

  • removing the fog of war

removing the fog of war

  • compromised graphics rendering drivers

compromised graphics rendering drivers

  • cheaters have more knowledge than they should have → passive che

cheaters have more knowledge than they should have → passive cheating ating

  • compromised software or data

compromised software or data

  • counter

counter-

  • measures in a networked environment

measures in a networked environment

  • centralized: server maintains integrity among the clients

centralized: server maintains integrity among the clients

  • distributed: nodes check the validity of each other’s commands t

distributed: nodes check the validity of each other’s commands to detect

  • detect

cheaters cheaters

Exploiting design defects Exploiting design defects

  • what can we do to poor designs!

what can we do to poor designs!

  • repair the observed defects with patches

repair the observed defects with patches

  • limit the original functionality to avoid the defects

limit the original functionality to avoid the defects

  • client authority abuse

client authority abuse

  • information from the clients is taken face

information from the clients is taken face-

  • value regardless its reliability

value regardless its reliability

  • unrecognized (or unheeded) features of the network

unrecognized (or unheeded) features of the network

  • peration when the latencies are high
  • peration when the latencies are high
  • coping with DoS and other attacks

coping with DoS and other attacks

Denial Denial-

  • of
  • f-
  • Service (DoS) Attack

Service (DoS) Attack

  • Attack types:

Attack types:

  • logic attack: exploit flaws in the software

logic attack: exploit flaws in the software

  • flooding attack: overwhelm the victim’s resources by sending a l

flooding attack: overwhelm the victim’s resources by sending a large arge number of spurious requests number of spurious requests

  • Distributed DoS attack: attack simultaneously from multiple

Distributed DoS attack: attack simultaneously from multiple (possibly cracked) hosts (possibly cracked) hosts

  • IP spoofing: forge the source address of the outgoing packets

IP spoofing: forge the source address of the outgoing packets

  • Consequences:

Consequences:

  • wasted bandwidth, connection blockages

wasted bandwidth, connection blockages

  • computational strain on the hosts

computational strain on the hosts

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SLIDE 4

4

Analysing Analysing DoS DoS Activity Activity

  • Backscatter

Backscatter analysis analysis

  • Spoofing

Spoofing using using random random source address source address

  • A

A host on the Internet host on the Internet receives unsolicited receives unsolicited responses responses

  • An attack of

An attack of m m packets, packets, monitor monitor n n addresses addresses

  • Expectation of observing an

Expectation of observing an attack: attack: E E( (X X) = ) = nm nm/2 /232

32

DoS DoS: Selected Results : Selected Results

  • Three

Three week week-

  • long

long logging logging periods, February 2001 periods, February 2001

  • >12,000

>12,000 attacks, attacks, >5,000 >5,000 distinct targets distinct targets

  • Significant number of

Significant number of attacks were attacks were directed against directed against

  • home machines

home machines

  • users

users running Internet Relay Chat (IRC) running Internet Relay Chat (IRC)

  • users

users with names that are sexually suggestive or incorporate themes o with names that are sexually suggestive or incorporate themes of f drug drug use use

  • users supporting multiplayer games

users supporting multiplayer games

  • In addition to

In addition to well well-

  • known

known Internet sites, a large range of small Internet sites, a large range of small and medium sized and medium sized businesses were targeted businesses were targeted

DoS: Most Attacked Top DoS: Most Attacked Top-

  • Level Domains

Level Domains

. net . com . r o . br . or g . edu . ca . de . uk

  • ther

unknown

Look Look-

  • ahead cheating

ahead cheating

p p1

1

p p2

2

a a1

1 = Rock

= Rock a a2

2 = Paper

= Paper a a2

2 = Paper

= Paper s s = 2 = 2 a a1

1 = Rock

= Rock s s = 0 = 0

Two problems Two problems

  • delaying one’s decision

delaying one’s decision

  • announce own action only after learning the opponent’s decision

announce own action only after learning the opponent’s decision

  • ne
  • ne-
  • to

to-

  • one and one
  • ne and one-
  • to

to-

  • many

many

  • inconsistent decisions

inconsistent decisions

  • announce different actions for the same turn to different oppone

announce different actions for the same turn to different opponents nts

  • ne
  • ne-
  • to

to-

  • many

many