1、計算機審計計算機審計 Hugh Yan Hugh YanElectronic Payment Systems and Security 電子支付系統(tǒng)和安全加密技術1網上支付原理網上支付原理2計算機審計計算機審計 Hugh Yan Hugh YanLearning Objectives 學習目的zDescribe typical electronic payment systems for EC描述電子商務典型的電子支付系統(tǒng)zIdentify the security requirements for safe electronic payments 識別安全電子支付的安全要求zDescribe

2、 the typical security schemes used to meet the security requirements 滿足安全要求的安全方案zIdentify the players and procedures of the electronic credit card system on the Internet 識別互聯網上電子信用卡系統(tǒng)的使用者和使用處理過程zDiscuss the relationship between SSL and SET protocols 討論SSL協議和SET協議之間的關系3計算機審計計算機審計 Hugh Yan Hugh YanzDi

3、scuss the relationship between electronic fund transfer and debit card 討論電子資金轉帳和借記卡之間的關系zDescribe the characteristics of a stored value card 描述一個儲值卡的特征zClassify and describe the types of IC cards used for payments 辨別和描述用于支付的IC卡的類型zDiscuss the characteristics of electronic check systems 討論電子支票系統(tǒng)的特征Le

4、arning Objectives (cont.)學習目的(繼續(xù)繼續(xù))4計算機審計計算機審計 Hugh Yan Hugh YanSSL Vs. SET: Who Will Win?SSL對SET:誰將贏?zA part of SSL (Secure Socket Layer) is available on customers browsers 加密套接字協議層yit is basically an encryption mechanism for order taking, queries and other applications SSL是一個基本的加密技術yit does not pr

5、otect against all security hazards預防安全威脅yit is mature, simple, and widely use 成熟簡單廣泛應用zSET ( Secure Electronic Transaction) is a very comprehensive security protocol 加密電子交易協議yit provides for privacy, authenticity, integrity, and, or repudiation 它提供私密、真實、完整、拒絕方面的安全保護yit is used very infrequently due

6、to its complexity and the need for a special card reader by the user 不常用、復雜yit may be abandoned if it is not simplified/improved 需改進5計算機審計計算機審計 Hugh Yan Hugh YanPayments, Protocols and Related Issues支付、協議、相關議題z SET Protocol is for Credit Card Payments 信用卡支付z Electronic Cash and Micropayments 電子貨幣和找零

7、z Electronic Fund Transfer on the Internet 互聯網上電子資金轉帳z Stored Value Cards and Electronic Cash 儲值卡和電子貨幣z Electronic Check Systems 電子支票系統(tǒng)6計算機審計計算機審計 Hugh Yan Hugh YanzSecurity requirements 安全要求Payments, Protocols and Related Issues (cont.)支付、協議、相關議題（繼續(xù)）yAuthentication: A way to verify the buyers ident

8、ity before payments are made 真實性鑒定 支付前的買主身份認定yIntegrity: Ensuring that information will not be accidentally or maliciously altered or destroyed, usually during transmission 完整性 信息不被偶然地或惡意地修改或破壞yEncryption: A process of making messages indecipherable except by those who have an authorized decryption

9、key 加密術 除非那些具有一個授權解密鑰匙的人可以解釋信息內容，加密技術使信息無法被解釋或閱讀yNon-repudiation: Merchants need protection against the customers unjustifiable denial of placed orders, and customers need protection against the merchants unjustifiable denial of past payment 不被拒絕 商人需要預防客戶對于發(fā)出定單的無正當理由的抵賴，客戶需要預防商人對于客戶過去支付的無正當理由的抵賴。7計算

10、機審計計算機審計 Hugh Yan Hugh YanSecurity Schemes 安全加密方案z Secret Key Cryptography (symmetric)密碼加密技術（對稱加密技術）Scrambled MessageOriginal MessageSenderInternetScrambled MessageKeysender (= Keyreceiver)Encryption加密加密Original MessageReceiverKeyreceiverDecryption解密解密對稱加密就如同一把有相同兩把鑰匙的鎖對稱加密就如同一把有相同兩把鑰匙的鎖, ,兩把鑰匙在不同兩把

11、鑰匙在不同的兩個人手中的兩個人手中, ,一個人加鎖一個人加鎖, ,另外一個人用同樣的鑰匙打開鎖另外一個人用同樣的鑰匙打開鎖 8計算機審計計算機審計 Hugh Yan Hugh YanzPublic Key Cryptography 公鑰加密技術SenderOriginal MessageScrambled MessageScrambled Message公鑰 Public KeyreceiverOriginal MessageReceiver私鑰Private KeyreceiverInternetSecurity Schemes (cont.)安全加密方案（繼續(xù)）MessageSenderO

12、riginal MessageScrambled MessageScrambled Message私鑰Private KeysenderOriginal MessageReceiver公鑰 Public KeysenderInternetDigitalSignature9計算機審計計算機審計 Hugh Yan Hugh YanzDigital Signature 數字簽名A digital signature is attached by a sender to a message encrypted in the receivers public key 一個數字簽名由發(fā)送者附加在通過用接收

13、者的公鑰加密的信息上The receiver is the only one that can read the message and at the same time he is assured that the message was indeed sent by the sender 接收者是唯一一個能夠閱讀信息的人，同時他被告知這個信息的確是由那個發(fā)送者發(fā)送的Sender encrypts a message with her private key 發(fā)送者用他發(fā)送者用他的私鑰加密了一個信息的私鑰加密了一個信息Any receiver with senders public key

14、can read it 任何接任何接收者用發(fā)送者的公鑰就能閱讀這收者用發(fā)送者的公鑰就能閱讀這個信息個信息Security Schemes (cont.)安全加密方案（繼續(xù)）yAnalogous to handwritten signature 類似手寫簽名10計算機審計計算機審計 Hugh Yan Hugh YanzCertificate 證書Name : “Richard”key-Exchange Key :Signature Key :Serial # : 29483756Other Data : 10236283025273Expires : 6/18/2005Signed : CAs

15、SignatureSecurity Schemes (cont.)安全加密方案（繼續(xù)）yIdentifying the holder of a public key (Key-Exchange)識別一個公鑰（密碼交換）的持有者yIssued by a trusted certificate authority (CA) 由一個認可認證機關（CA）發(fā)出11計算機審計計算機審計 Hugh Yan Hugh YanzCertificate Authority - e.g. VeriSign認證機構 例如：驗證簽名RCABCAGCACCAMCAPCARCA : Root Certificate Aut

16、horityBCA : Brand Certificate AuthorityGCA : Geo-political Certificate AuthorityCCA : Cardholder Certificate AuthorityMCA : Merchant Certificate AuthorityPCA : Payment Gateway Certificate AuthorityHierarchy of Certificate Authorities 認證機構的層級結構認證機構的層級結構Certificate authority needs to be verified by a

17、government or well trusted entity ( e.g., post office)Security Schemes (cont.) Security Schemes (cont.)安全加密方案（繼續(xù)）yPublic or private, comes in levels (hierarchy)yA trusted third party services 一個認可的第三方服務yIssuer of digital certificates 數字認證的發(fā)出者yVerifying that a public key indeed belongs to a certain i

18、ndividual12計算機審計計算機審計 Hugh Yan Hugh YanElectronic Credit Card System on the Internet互聯網上的電子信用卡系統(tǒng)互聯網上的電子信用卡系統(tǒng)zThe Players 信用卡使用者yCardholder 卡持有者yMerchant (seller) 銷售商yIssuer (your bank)發(fā)卡銀行yAcquirer (merchants financial institution, acquires the sales slips) 銷售商的財務結算機構，獲得銷售商的銷售單和顧客支付給銷售商的金額，是銷售商的結算銀行

19、yBrand (VISA, Master Card) 卡的種類13計算機審計計算機審計 Hugh Yan Hugh Yanz The process of using credit cards offline 離線使用信用卡的操作過程A cardholder requests the issuance of a card brand (like Visa and MasterCard) to an issuer bank in which the cardholder may have an account. 申請發(fā)卡Electronic Credit Card System on the I

20、nternet (cont.) 互聯網上的電子信用卡系統(tǒng)互聯網上的電子信用卡系統(tǒng)The authorization of card issuance by the issuer bank, or its designated brand company, may require customers physical visit to an office. 銀行審查A plastic card is physically delivered to the customers address by mail.發(fā)出The card can be in effect as the cardholder

21、 calls the bank for initiation and signs on the back of the card. 起用，持有者在卡的背面簽名The cardholder shows the card to a merchant to pay a requested amount. Then the merchant asks for approval from the brand company. 持卡人支付時，商戶請求銀行允許支付Upon the approval, the merchant requests payment to the merchants acquire

22、r bank, and pays fee for the service. This process is called a Capturing process銷售商結算銀行獲得銷售單The acquirer bank requests the issuer bank to pay for the credit amount. 銷售商結算銀行請求發(fā)卡銀行支付消費額Cardholder持卡人Merchant商戶credit card信用卡Card Brand CompanyPayment authorization, payment data 支付數據Issuer BankCardholderA

23、ccount持卡人帳戶Acquirer BankMerchantAccount銷售商帳戶account debit datapayment dataCredit Card Procedure信用卡操作過程 (offline and online在線和離線)14payment data支付數據amount transfer轉付金額電子商務和電子政務電子商務和電子政務 閻虎勤閻虎勤Secure Electronic Transaction (SET) Protocol加密電子交易協議（SET）1. The message is hashed to a prefixed length of mess

24、age digest. 一個信息被雜湊（有時候常常是通過一個雜湊函數）成一個定長信息消化元。2. The message digest is encrypted with the senders private signature key, and a digital signature is created. 這個信息消化元用發(fā)送者私鑰簽名加密，這樣，一個數字簽名就被創(chuàng)造出來了。3. The composition of message, digital signature, and Senders certificate is encrypted with the symmetric ke

25、y which is generated at senders computer for every transaction. The result is an encrypted message. SET protocol uses the DES algorithm instead of RSA for encryption because DES can be executed much faster than RSA. 信息內容、數字簽名、新加上發(fā)送者的認證書一起被用對稱鑰匙加密，形成一個加密信息。4. The Symmetric key itself is encrypted wit

26、h the receivers public key which was sent to the sender in advance. The result is a digital envelope. 對稱鑰匙被預先發(fā)送給發(fā)送者的接收者的公鑰加密，這樣就形成一個數字信封。15zSenders Computer 發(fā)送者的計算機電子商務和電子政務電子商務和電子政務 閻虎勤閻虎勤Senders Computer 發(fā)送者的計算機發(fā)送者的計算機Senders Private Signature KeySenders發(fā)送者 Certificate認證書數字簽名數字簽名+Message原始信息+Digit

27、al Signature數字簽名Receivers 接收者Certificate認證書Encrypt 加密Symmetric Key對稱鑰匙Encrypted Message加密信息Receivers 接收者公鑰Key-Exchange KeyEncrypt 加密DigitalEnvelope數字信封Message原始信息Message Digest信息消化元16電子商務和電子政務 閻虎勤5. The encrypted message and digital envelope are transmitted to receivers computer via the Internet. 加密

28、信息和數字信封被通過互聯網發(fā)送到接收者的計算機。6. The digital envelope is decrypted with receivers private exchange key. 數字信封被用接收者的私人交換鑰匙（私鑰）解蜜。7. Using the restored symmetric key, the encrypted message can be restored to the message, digital signature, and senders certificate. 使用恢復出來的對稱鑰匙，則加密信息能夠被恢復成原始信息、數字簽名、和發(fā)送者的認證書。8.

29、 To confirm the integrity, the digital signature is decrypted by senders public key, obtaining the message digest. 為確保數據的完整性，數字簽名被用發(fā)送者的公鑰解密，從而得到信息消化元。9. The delivered message is hashed to generate message. 反雜湊獲得原始信息 10. The message digests obtained by steps 8 and 9 respectively, are compared by the

30、receiver to confirm whether there was any change during the transmission. This step confirms the integrity. 在8、9步后得到信息，接收者通過比較來確信是否在傳輸中間發(fā)生了任何變化。這一步保證了信息的完整性。zReceivers Computer 接收者的計算機Secure Electronic Transaction (SET) Protocol (cont.)加密電子交易協議（SET）（繼續(xù)）17電子商務和電子政務電子商務和電子政務 閻虎勤閻虎勤Receivers Computer接收

31、者的計算機接收者的計算機DecryptSymmetric Key對稱解密Encrypted Message加密信息Senders 發(fā)送者Certificate認證書數字簽名數字簽名+Message原始信息Compare 比較比較DigitalEnvelope數字信封Receivers Private Key-Exchange Key接收者私鑰Decrypt 解密Message Digest 信息消化元Digital Signature 數字簽名Senders Public Signature Key發(fā)送者公鑰Decrypt 解密Message Digest 信息消化元18 Prentice H

32、all, 2000Entities of SET Protocol in Cyber Shopping 協議（SET）下的網上購物IC CardReaderIC卡讀卡器Customer xCustomer yWith Digital Wallets數字錢包Certificate認證Authority機關Electronic Shopping MallMerchant AMerchant BCredit CardBrandProtocolX.25Payment Gateway支付網關 19電子商務和電子政務電子商務和電子政務 閻虎勤閻虎勤20計算機審計計算機審計 Hugh Yan Hugh Ya

33、nSET Vs. SSL 兩個協議之間的對比Secure Electronic Transaction (SET)加密電子交易協議（SET）Secure Socket Layer (SSL)加密字套接層協議（SSL）Complex 復雜復雜Simple簡單簡單SET is tailored to the credit card payment to the merchants. 信用卡信用卡SSL is a protocol for general-purpose secure message exchanges (encryption). 普通加密普通加密SET protocol hides

34、 the customers credit card information from merchants, and also hides the order information to banks, to protect privacy. This scheme is called dual signature. 雙簽名雙簽名SSL protocol may use a certificate, but there is no payment gateway. So, the merchants need to receive both the ordering information a

35、nd credit card information, because the capturing process should be initiated by the merchants.無支付網關無支付網關21計算機審計計算機審計 Hugh Yan Hugh YanElectronic Fund Transfer (EFT) on the Internet 互聯網上的電子資金轉帳（EFT）An Architecture of Electronic Fund Transfer on the InternetInternetPayer付款人Cyber BankBankCyber BankPay

36、ee收款人Automated自動Clearinghouse清算VANBankVANPaymentGateway支付網關PaymentGateway支付網關22計算機審計計算機審計 Hugh Yan Hugh YanDebit Cards 借記卡借記卡zA delivery vehicle of cash in an electronic form 一個電子貨幣的運鈔車zMondex, VisaCash applied this approach 借記卡Mondex和VisaCash適合這種方式 zEither anonymous or onymous 匿名或具名zCyberCash has c

37、ommercialized a debit card named CyberCoin as a medium of micropayments on the Internet 網絡貨幣CyberCash已經商業(yè)化了一個借記卡名為網絡硬幣CyberCoin作為互聯網上找零的一個中介。23計算機審計計算機審計 Hugh Yan Hugh YanFinancial EDI 財務EDIzIt is an EDI used for financial transactions 用于財務轉帳yEDI is a standardized way of exchanging messages between

38、businesses 企業(yè)間信息交換的一個標準方式y(tǒng)EFT can be implemented using a Financial EDI system 使用一個財務EDI系統(tǒng)EFT能夠被應用zSafe Financial EDI needs to adopt a security scheme used for the SSL protocol接受一個加密技術用于SSLzExtranet encrypts the packets exchanged between senders and receivers using the public key cryptography 企業(yè)間網絡（

39、Extranet ）使用公鑰加密技術加密發(fā)送者和接收者之間交換的郵包。24計算機審計計算機審計 Hugh Yan Hugh YanElectronic Cash and Micropayments電子貨幣和找零zSmart Cards 智能卡yThe concept of e-cash is used in the non-Internet environment 電子貨幣的概念被用在非互聯網環(huán)境yPlastic cards with magnetic stripes (old technology)具有磁條的塑料卡（舊技術）yIncludes IC chips with programmab

40、le functions on them which makes cards “smart” 包含具有程序功能的IC芯片，芯片使卡更“聰明”。yOne e-cash card for one application 一種卡一種應用yRecharge the card only at designated locations, such as bank office or a kiosk. Future: recharge at your PC 重新寫卡只能在指定地點進行，如銀行辦公室或一個工作間。將來可在PC上進行。ye.g. Mondex & VisaCash 例如： Mondex

41、& VisaCash 25計算機審計計算機審計 Hugh Yan Hugh YanVisaCash Makes Shopping Easy智能卡VisaCash使購物更容易zShopping with VisaCash 使用智能卡購物zAdding money to the card 增加存款到卡中zPayments in a new era of electronic shopping 支付在一個新的電子購物區(qū)zPaying on the Internet 在互聯網上支付26計算機審計計算機審計 Hugh Yan Hugh YanElectronic Money 電子貨幣zDigiC

42、ash 數字貨幣yThe analogy of paper money or coins 類似紙幣或硬幣yExpensive, as each payment transaction must be reported to the bank and recorded 昂貴，每一次支付轉帳都必須被報告給銀行且被記錄。yConflict with the role of central banks bill issuance 與中央銀行的貨幣發(fā)行角色有矛盾。yLegally, DigiCash is not supposed to issue more than an electronic gif

43、t certificate even though it may be accepted by a wide number of member stores 合法地講，雖然數字貨幣可能被一個龐大的會員商場接受，但是它不會被認為會發(fā)行超過一個電子禮品證書。27計算機審計計算機審計 Hugh Yan Hugh YanzStored Value Cards 儲值卡Electronic Money (cont.)電子貨幣（繼續(xù)）yNo issuance of money 沒有貨幣的發(fā)行yDebit card a delivering vehicle of cash in an electronic f

44、orm 借記卡 一個電子格式的貨幣轉運車yEither anonymous or onymous 匿名或具名yAdvantage of an anonymous card 匿名卡的優(yōu)點xthe card may be given from one person to another 該卡可以被一個人交給另外一個人使用yAlso implemented on the Internet without employment of an IC card 如果沒有使用IC卡也可以在互聯網上使用28計算機審計計算機審計 Hugh Yan Hugh YanzSmart card-based e-cash

45、基于智能卡的電子貨幣yCan be recharged at home through the Internet 可以在家中通過互聯網被刷新yCan be used on the Internet as well as in a non-Internet environment 能夠被在互聯網環(huán)境下被使用，如同在非互聯網環(huán)境下被使用一樣好zCeiling of Stored Values 儲值的上限yTo prevent the abuse of stored values 預防儲值濫用yS$500 in Singapore; HK$3,000 in Hong KongzMultiple Cu

46、rrencies 多種貨幣yCan be used for cross border payments 交叉支付Electronic Money (cont.)電子貨幣（繼續(xù)）29計算機審計計算機審計 Hugh Yan Hugh YanContactless IC Cards 無接觸IC卡zProximity Card 功能接近的卡yUsed to access buildings and for paying in buses and other transportation systems 用來進入大樓、支付公交車票、和其它運輸系統(tǒng)yBus, subway and toll card in

47、 many cities 在許多城市使用的公交車、地鐵和路橋卡zAmplified Remote Sensing Card 放大的遠程感應卡yGood for a range of up to 100 feet, and can be used for tolling moving vehicles at gates 能夠被機動車輛在門口用來支付路橋費，最遠可達到100英尺yPay toll without stopping (e.g. Highway 91 in California) 支付路橋費而不用停車30計算機審計計算機審計 Hugh Yan Hugh YanElectronic Ch

48、eck Systems 電子支票系統(tǒng)CheckSignatureRemittanceInvoiceSecure EnvelopeRemittanceCheckSignatureCertificateCertificateRemittanceSecure EnvelopeCertificateCertificateEndorsementCertificateCertificateSignature “Card”Signature“Card”WorkstationMall statementE-Check line itemPayers Bank付款人銀行借款帳戶Debit accountPaye

49、es Bank收款人銀行信用帳戶Credit accountE- MailWWWACHECPClear Check清算支票Deposit checkPayer付款者Payee收款人E-mailAccountReceivableProcedure of Financial Service Technology Consortium Prototype金融服務技術集團的處理模型31計算機審計計算機審計 Hugh Yan Hugh YanzElectronic Checkbook 電子支票簿Electronic Check Systems (cont.)電子支票系統(tǒng)（繼續(xù)）yCounterpart

50、of electronic wallet 對應電子錢包yTo be integrated with the accounting information system of business buyers and with the payment server of sellers 被與商業(yè)購買者會計信息系統(tǒng)和銷售商的支付服務系統(tǒng)一起綜合起來yTo save the electronic invoice and receipt of payment in the buyers and sellers computers for future retrieval 保存電子發(fā)票和支付收據在購買者和

51、銷售者的計算機內，以備今后使用yExample : SafeCheckyUsed mainly in B2B 主要用于B2B業(yè)務Payers checkbook agentPayees check-receipt agentPayerPayeeIssue a checkReceiptA/CDBA/CDBcontrolagent of payers bankcontrolagent of payees bankclearingCheckbook,screened resultRequest of screening checkissuancepresentreportpayers bankpay

52、ees bankInternetThe Architecture of SafeCheck32電子商務和電子政務電子商務和電子政務 閻虎勤閻虎勤33計算機審計計算機審計 Hugh Yan Hugh YanIntegrating Payment Methods 綜合支付方法zTwo potential consolidations:yThe on-line electronic check is merging with EFTyThe electronic check with a designated settlement date is merging with electronic cr

53、edit cardszSecurity First Network Bank (SFNB)yFirst cyberbankyLower service charges to challenge the service fees of traditional bankszVisayVisaCash is a debit cardyePay is an EFT service34計算機審計計算機審計 Hugh Yan Hugh YanHow Many Cards are Appropriate?An onymous cardis necessary tokeep the certificates forcredit cards, EFT, andelectronic checkbooksThe stored value inIC card can be deliveredin an anonym