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- 1 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Secure Electronic Commerce
System software laboratory 석사 2 학기 박 정 호
( Chap.2 The Internet )
- 2 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Computer NetworkingComputer Networking
Distributed Application Single PC application - W.P, spreadsheets Multiple PC application - E-mail Distributed Application Computer network - transferring data between systems System
Equipment which is connected to a computer networkH/W & S/W running on that equipment
• ex) A network-connected desktop PC, ATM, POS devices
Client-server applications
File server Database server
Mail server Information-retrieval server
File server Database server
Mail server Information-retrieval server
serverClient systemClient system
End-user
…...End-user
- 3 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
Computer Networks Data item
Conveyed from one system to anotherRepresentation of a information
Protocol Set of rules understood by systems that intercommunicate
Multiple layer of protocol• operate independently of each other
Link or subnetwork layer • protocol to support the transfer of a string of data bits
Network layer • protocol to support the delivery of a packet Transport layer • protocol to ensure that all data packet deliver and no packets are lost
Application layer • protocol understood by the application S/W components in the end-systems
- 4 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
TCP/IP 프로토콜 계층TCP/IP 프로토콜 계층
Layer 7Application
Layer 6Presentation
Layer 5Session
Layer 4Transport
Layer 3Network
Layer 2Link
Layer 1Physical
NetworkInterface
andHardware
Internet
Transport
Application
INTERNET PROTOCOL
TCP UDP
NETWORK INTERFACEAND HARDWARE
ICMPARP RARP
APPLICATIONS
FTPSMTP
TELNETX-WINDOWS
LPR, LPDREXEC
KERBEROSDNS
USERRPCNFS
PORTMAP
TFTPSNMP
ROUTEDNCS
MAC address
IP address
Segments Datagrams
Stream sockets Datagram sockets
ports
ISO Model (OSI) TCP/IP Model
- 5 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
Internet Both a technology and a live, massive computer network Foundation
U.S Department of Defense in 1969Support the establishment of connections between computers
Expansion ARPA (DARPA) in 1970s
• interconnecting computers in University and government research institutions across the U.S.
• become available for commercial exploitation and international Main technological achievement
Development of public-domain network protocols Two protocols
Transmission Control Protocol(TCP) : transport layer Internet Protocol(IP) : network layer
- 6 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Electronic messaging
(e-mail)
Network news(Newsgroup)
File transfer(FTP)
World Wide Web(WWW)
Information browsing(Gopher)
Remote login(Telnet)
Wide Area Information
Service(WAIS)
Internet ApplicationsInternet Applications
- 7 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Cont’dCont’d
Electronic MessagingSend a message to one or more recipients
Has some problem• message compromise only text
• must deal with multimedia data
Multipurpose Internet Mail Extensions(MIME)• transfer of structured, multimedia messages
Mail gatewayMail server Mail server
S1…..S2 R1…..R2
X.400 X.400
- 8 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
WEB server
Cont’dCont’d
World Wide WebSupport the delivery of hypermedia documents
• Contain multimedia information
• Include hypertext references(links) to other documents
• HTTP(Hyper Text Transfer Protocol)
– application layer to access webserver
Has a unique identifier
URLN.CI .Eetc
Browser
userHTTP
- 9 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Internet CommunityInternet Community
InternetUsers
Internet Accessprovider
Host-based Service provider
Internet content provider
Internet ResearchTask Force(IRTF)
Internet EngineeringTask Force(IETF)
InterNIC AssignedNumbers
Authority(IANA)
InterNIC Directory and Database
Services
Internet Service Providers
Internet Activities Board
The InterNIC
- 11 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
Internet Activities Board and Internet Standards
Standards track Proposed standard Draft standard Standard
IESGIESG
IRTFIETF
IAB
- 12 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Cont’dCont’d
InterNIC(Internet Network Information Center) Major component of the Internet’s infrastructure
InterNIC directory and database services
• operated by AT&T Corp
• including distribution of many Internet publications
InterNIC registration services
• provided by Network Solutions, Inc.
• support Domain
– the assignment of names to network or organization
- 13 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
인터넷의 IP 주소 체계인터넷의 IP 주소 체계
네트워크 주소 (7) 호스트주소 (24)1
네트워크 주소 (14) 호스트주소 (16)1
네트워크 주소 (21) 호스트주소 (8)
다중 전송용 (Multicast) 주소 (28)1
0
1 01
1 01
예약 (27)1 1 1 01
8 16 24
클래스 A
클래스 B
클래스 C
클래스 D
클래스 E
클래스 네트워크 수 호스트 수(네트워크 당)
주소 범위
A 27 = 128 224 = 16,777,216 0.0.0.0 – 127.255.255.255
B 214 = 16,384 216 = 65,536 128.0.0.0 – 191.255.255.255
C 221 = 2,097,152 28 = 256 192.0.0.0 – 223.255.255.255
D 228 = 268,435,456 224.0.0.0 – 239.255.255.255
E 227 = 134,217,728 240.0.0.0 – 247.255.255.255
- 14 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Cont’dCont’d
Service Providers Access serviceHost-based servicesContent
Internet PublicationsRequests for Comments (RFC) seriesAnother important series - Internet Drafts
Working Together for SecurityRFC1281(guideline for the secure operation of the internet)
• work together to achieve a secure environment– users – computer and network service provider– vendors and system developers
- 15 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
EC on the InternetEC on the Internet
EDIEDI
Electronic Data InterchangeElectronic Data Interchange One of the forms of electronic commerceOne of the forms of electronic commerce
• Purchase ordersPurchase orders• InvoicesInvoices• Payment advicesPayment advices
The X12 standardsThe X12 standardsThe EDIFACT standardsThe EDIFACT standards
- 16 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
EDIEDI VANVAN+
• Data communications services Data communications services • Software, security, recovery of lost dataSoftware, security, recovery of lost data
transaction tracing, auditingtransaction tracing, auditing
ClientClient
EDIEDI ClientClient
• Communications linesCommunications lines• Dial up linksDial up links• Mainframe terminal emulationMainframe terminal emulation• Packet-switching data networksPacket-switching data networks
- 17 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
EDI VANSEDI VANS InternetInternet ClientClient
ClientClientVANVAN
• High costHigh cost
• Low costLow cost
• Didn’t provide basic data communications serviceDidn’t provide basic data communications service• Provide auxiliary serviceProvide auxiliary service• Using the natural technology of electronic massagingUsing the natural technology of electronic massaging
- 18 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
EDI EDI InternetInternet ClientClient
MIMEMIME
• Providing an ideal frameworkProviding an ideal framework
EDI UserEDI UserEDI UserEDI User EDI UserEDI UserEDI UserEDI User
VANVANVANVAN AnotherAnotherAnotherAnother
• Using the MIME content typeUsing the MIME content type • MIME have three content typesMIME have three content types
- 19 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
• Open Electronic CommerceOpen Electronic Commerce
EDI transactionsEDI transactionsEDI transactionsEDI transactions require • technical & administrative protocolstechnical & administrative protocols• legal agreementslegal agreements
BuyersBuyers
WEBWEB
SellersSellers
E-mailE-mail
• Finding easilyFinding easily
• GoodsGoods• ServiceService
• Business agreementsBusiness agreements• Paper documentsPaper documents
• New electronic commerceNew electronic commerce
Without pre-negotiated, customized, bilateral agreementsWithout pre-negotiated, customized, bilateral agreements
- 20 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
Example Transaction ScenariosExample Transaction Scenarios
Vera Buys a Lathe
Decides on a model offered by Danielle’s Machine Markers
Investigates the vendor electronicallyFills out the electronic order formTransmits the order via the internet
Checks the order and confirms the order by returning an electronic invoice
Pays for the lathe using a network-based process
Vera
Danielle :
Vera :
Danielle : Delivers the lathe to Vera’s manufacturing
Web
- 21 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
InternetInternet
Example Transaction ScenariosExample Transaction Scenarios
Vera Buys a Lathe
Vera Danielle’sMachineMarker
Launches Web broswerlathe 검색
lathe 목록 표시
모델 결정전자주문서 작성 및 전송
전자주문서 수신
송장 발송
송장 수신
요금 지불- 신용카드 .- 전자화폐
Lathe 탁송Lathe 수취
- 22 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
cont’dcont’d
Inter-corporate Trading Using e-mail-based electronic commerce
Because e-mail present too many risks
Needs to incorporate the following safeguards
Originator of every message must be securely authenticated
All messages must be confidentiality-protected
Nola’s Electronic Market Faces some substantial risks because she don’t know who they are
- 23 -SYSTEM SOFTWARE Lab.SYSTEM SOFTWARE Lab.
일자 : 98-03-19
SummarySummary
Computer networkmeans for transferring data depends on network protocol
Internet public network + private networkinternet protocol = TCP/IP
Internet applicationelectronic messaging & WWW MIME(Multi-purpose Internet Mail Extensions)
Internet community users, service providers, IAB(Internet Activities Board), InterNIC
EC(Electronic Commerce)
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