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Applications of Computers Lecture-3 E-Commerce Almost all major companies have their homes on the web, mainly for advertising Companies were reluctant towards e-commerce but now it is picking up The most revolutionary e-commerce is between business and customer

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e commerce
E-Commerce
  • Almost all major companies have their homes on the web, mainly for advertising
  • Companies were reluctant towards e-commerce but now it is picking up
  • The most revolutionary e-commerce is between business and customer
  • Business-business e-commerce is already developed
e commerce requirements
E-Commerce Requirements
  • E-commerce between customer and business requires several functions
  • For example, auction sites should have the capability to track bids by various people
  • Also, multi-vendor selling sites should support tracking of multiple companies
  • Transactions between customers and the e-commerce site should be safe and secure
the credit card concerns
The Credit Card Concerns
  • Almost all e-commerce sites offer credit card support
  • A customer who wants to buy something pays with credit card
  • The credit card information is transmitted through the public network and it can be tapped by someone in the middle
encryption and data security
Encryption and Data Security
  • For successful e-commerce, we must ensure that the sensitive data has been encrypted and secured
  • Encryption transforms the data using a “key” into a value that is meaningless in its normal form
  • This encrypted value can only be decrypted by authorized agency or person
securing the connection
Securing the Connection
  • For protecting the credit card info, it is transmitted under SSL (secure sockets layer)
  • It means the card info is encrypted and it is very difficult to break the code by an intruder
  • Surprisingly, the misuse of the card info by employees is a more serious concern
encryption and data security7
Encryption and Data Security
  • For successful e-commerce, we must ensure that the sensitive data has been encrypted and secured
  • Encryption transforms the data using a “key” into a value that is meaningless in its normal form
  • This encrypted value can only be decrypted by authorized agency or person
encryption basics
Encryption Basics
  • For encryption, XOR logical operation is widely used
  • The data to be encrypted is XORed with the key
  • XOR has the property that it can transform a binary value into another totally different value. This encrypted value is sent instead of the original value
  • The recipient performs XOR of the received encrypted value with the key, restoring original value
class example
Class Example
  • The data to be sent is: 0111 1011
  • The 4-bit key is 1010
  • SENDER: Encrypt the data and send it to the recipient
  • Encrypted Data is obtained by repeatedly performing XOR operation with the key
  • First Four bits 0111 XOR 1010 gives the result 1101
class example10
Class Example
  • Next Four bits 1011 XOR 1010 gives the result 0001
  • RECIPIENT: Decrypt the data
  • First Four bits 1101 XOR 1010 gives the result 0111 (original data recovered)
  • Next Four bits 0001 XOR 1010 gives the result 1011 (original data recovered)
encryption keys
Encryption Keys
  • There are two types of encryption schemes in use
  • In symmetric or secret key ciphers, the encryption and decryption keys are symmetric and identical
  • As an example, consider this diagram then encrypt following message with your own encryption scheme
  • “Please transfer six million dollars into my checking account”
symmetric cipher
Symmetric Cipher

Adapted for academic use from “Exploring The Digital Domain” by Abernethy Allen, ITP 1999

symmetric cipher13
Symmetric Cipher
  • In symmetric secret key cipher, the key must be sent to recipient, otherwise the message cannot be decrypted
  • Sending the key on public network is like putting your house key in locksmith’s shop and allowing everyone to duplicate it
  • Alternatives are to restrict access to secret key to a few individuals
slide14
DES
  • DES (Data Encryption Standard) is one example of symmetric key encryption
  • DES uses a 56-bit key which can be doubled in length to 112 bits
  • Breaking messages encrypted with DES would require a considerable amount of computing time and effort
alternate payment methods
Alternate Payment Methods
  • DIGICASH is an alternate payment method that does not use credit cards for online buying
  • Customer opens an account and an electronic wallet is created at customer’s machine
  • Customer is able to create digital coins that are certified by the bank
digicash is now ecash
Digicash is now eCash
  • http://www.ecashtechnologies.com/
  • The new p2p technology is developed by the eCash technologies
  • Refer to the link below:
  • http://www.ecashtechnologies.com/Solutions/p2p.asp
alternate payment methods17
Alternate Payment Methods
  • The bank attaches a digital signature to each digital coin
  • Thus, the customer can send digital cash to the vendor and buy anonymously
  • VIRTUAL PIN allows credit card charges without transmitting card number
  • The bank holds customer’s credit card information and issue a virtual PIN to customer
alternate payment methods18
Alternate Payment Methods
  • Customer specifies virtual PIN to a merchant when charging something to credit card
  • Merchant sends this PIN to bank for verification
  • Bank requests customer authorization via email and on confirmation, charges the amount of sale to customer’s credit card
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