Secure Electronic Commerce Chap 2 The Internet

Secure Electronic Commerce ( Chap. 2 The Internet ) System software laboratory 석사 2 학기 박정호 SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 1

Computer Networking z Distributed Application y Single PC application - W. P, spreadsheets y Multiple PC application - E-mail Distributed Application y Computer network - transferring data between systems y System x. Equipment which is connected to a computer network x. H/W & S/W running on that equipment • ex) A network-connected desktop PC, ATM, POS devices y Client-server applications server File server Database server Mail server Information-retrieval server End-user Client system …. . . End-user SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 2

cont’d z Computer Networks y Data item x. Conveyed from one system to another x. Representation of a information y Protocol x. Set of rules understood by systems that intercommunicate y Multiple layer of protocol • operate independently of each other x. Link or subnetwork layer • protocol to support the transfer of a string of data bits x. 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 x. Application layer • protocol understood by the application S/W components in the end-systems SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 3

TCP/IP 프로토콜 계층 ISO Model (OSI) TCP/IP Model APPLICATIONS Layer 7 Application Layer 6 Presentation FTP SMTP TELNET X-WINDOWS LPR, LPD REXEC Application Layer 5 Session Stream sockets Layer 4 Transport Layer 3 Network TCP Segments Transport Internet Layer 2 Link Layer 1 Physical KERBEROS DNS USER RPC NFS PORTMAP TFTP SNMP ROUTED NCS Datagram sockets ports UDP Datagrams ICMP ARP RARP INTERNET PROTOCOL IP address NETWORK INTERFACE AND HARDWARE Network Interface and Hardware MAC address SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 4

cont’d z Internet y Both a technology and a live, massive computer network y Foundation x. U. S Department of Defense in 1969 x. Support the establishment of connections between computers y Expansion x ARPA (DARPA) in 1970 s • interconnecting computers in University and government research institutions across the U. S. • become available for commercial exploitation and international y Main technological achievement x Development of public-domain network protocols y Two protocols x. Transmission Control Protocol(TCP) : transport layer x Internet Protocol(IP) : network layer SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 5

Internet Applications Electronic messaging (e-mail) Remote login (Telnet) Network news (Newsgroup) Information browsing (Gopher) World Wide Web (WWW) Wide Area Information Service(WAIS) File transfer (FTP) SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 6

Cont’d y. Electronic Messaging x. Send a message to one or more recipients Mail server X. 400 Mail gateway X. 400 S 1…. . S 2 Mail server R 1…. . R 2 x. Has some problem • message compromise only text • must deal with multimedia data x. Multipurpose Internet Mail Extensions(MIME) • transfer of structured, multimedia messages SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 7

Cont’d y. World Wide Web x. Support 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 x. Has a unique identifier user N. C I. E etc Browser HTTP URL WEB server SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 8

Internet Community Internet Access provider Host-based Service provider Internet content provider Inter. NIC Assigned Numbers Authority(IANA) Inter. NIC Directory and Database Services The Inter. NIC Internet Service Providers Internet Users Internet Activities Board Internet Engineering Task Force(IETF) Internet Research Task Force(IRTF) SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 9

SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 10

cont’d z Internet Activities Board and Internet Standards IESG IETF IRTF IAB z Standards track y Proposed standard y Draft standard y Standard SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 11

Cont’d z Inter. NIC(Internet Network Information Center) y Major component of the Internet’s infrastructure x. Inter. NIC directory and database services • operated by AT&T Corp • including distribution of many Internet publications x. Inter. NIC registration services • provided by Network Solutions, Inc. • support Domain – the assignment of names to network or organization SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 12

인터넷의 IP 주소 체계 8 클래스 A 1 네트워크 주소(7) 클래스 B 1 0 클래스 C 1 1 0 클래스 D 1 1 1 0 클래스 E 16 1 1 0 24 호스트주소(24) 네트워크 주소(14) 호스트주소(16) 네트워크 주소(21) 호스트주소(8) 다중 전송용(Multicast) 주소(28) 예약(27) SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 13

Cont’d y. Service Providers x. Access service x. Host-based services x. Content y Internet Publications x. Requests for Comments (RFC) series x. Another important series - Internet Drafts y. Working Together for Security x. RFC 1281(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 SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 14

EC on the Internet z EDI y Electronic Data Interchange y One of the forms of electronic commerce The X 12 standards The EDIFACT standards • Purchase orders • Invoices • Payment advices SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 15

cont’d EDI + VAN Client • Data communications services • Software, security, recovery of lost data transaction tracing, auditing EDI Client • Communications lines • Dial up links • Mainframe terminal emulation • Packet-switching data networks SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 16

cont’d VAN Client • High cost EDI VANS Client Internet • Low cost • Didn’t provide basic data communications service • Provide auxiliary service • Using the natural technology of electronic massaging SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 17

cont’d EDI Internet Client MIME • Providing an ideal framework EDI User • Using the MIME content type • MIME have three content types VAN Another SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 18

cont’d • Open Electronic Commerce EDI transactions Buyers • technical & administrative protocols • legal agreements require Sellers • Finding easily • Goods • Service WEB E-mail • Business agreements • Paper documents • New electronic commerce Without pre-negotiated, customized, bilateral agreements SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 19

Example Transaction Scenarios z Vera Buys a Lathe Web Decides on a model offered by Danielle’s Machine Markers Investigates the vendor electronically Fills out the electronic order form Transmits the order via the internet Vera Danielle : Vera : Danielle : Checks the order and confirms the order by returning an electronic invoice Pays for the lathe using a network-based process Delivers the lathe to Vera’s manufacturing SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 20

Example Transaction Scenarios z Vera Buys a Lathe Launches Web broswer lathe 검색 lathe 목록 표시 모델 결정 전자주문서 작성 및 전송 송장 수신 Vera 요금 지불 - 신용카드. - 전자화폐 Lathe 수취 Internet 전자주문서 수신 송장 발송 Lathe 탁송 Danielle’s Machine Marker SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 21

cont’d z Inter-corporate Trading y Using e-mail-based electronic commerce y Because e-mail present too many risks y Needs to incorporate the following safeguards x. Originator of every message must be securely authenticated x. All messages must be confidentiality-protected z Nola’s Electronic Market y Faces some substantial risks because she don’t know who they are SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 22

Summary y. Computer network xmeans for transferring data xdepends on network protocol y. Internet xpublic network + private network xinternet protocol = TCP/IP y. Internet application xelectronic messaging & WWW x. MIME(Multi-purpose Internet Mail Extensions) y. Internet community xusers, service providers, IAB(Internet Activities Board), Inter. NIC y. EC(Electronic Commerce) SYSTEM SOFTWARE Lab. 일자: 98 -03 -19 23