Applications of computers lecture 3
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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

  • 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


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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


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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


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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


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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


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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


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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


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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


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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)


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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”


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Symmetric Cipher

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


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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


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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


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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


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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


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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


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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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