ECommerce Infrastructure

1
E-CommerceInfrastructure Security

• Lecture 4
• Hosting Models
• .NET Overview
• Cryptography

2
An Interesting Story

• Managing large-scale courses
• System in use designed 10 years ago
• Has evolved into a scalable system
• Manages over 3000 students
• Over 200 TAs
• Many different courses

3
Entropy Kicks In

• Entropy states that everything moves from a
  complex system to breakdown
• Interesting to think how this coincides with the
  theory evolution
• System is plagued by entropy!

4
Current Problems

• Assignments lost
• Grades lost
• Inordinate amount of time spent hacking the
  system
• Dedicated, much-needed person required
• Stability of personnel!

5
Silver Lining?

• Wheres the fix?
• The existing system has been patched so much that
• Its not stable
• Its not viable to continue its upkeep
• Its not the Universitys mission to develop
  maintain software!

6
The Classic Problem

• Build (internal)
• vs.
• Buy (another company)

7
Societys Complexity

• More and more, companies (and individuals) are
• Specializing in skills
• Increasingly reliant upon each other
• Have no idea how to do things other than their
  specialization
• Example making pies
• Cost effective, but with drawbacks

8
The Least Common Denominator

• Companies are interested in increasing sales
• Thus they will want to maximize their market
  potential
• This often comes at the price of specialization
  lost

9
Our Solution

• We had to find an outside vendor
• Manage the courses and the students
• Allow for an easier interface
• Reliability a must!

10
Enter WebCT

• New functionality made it an option
• The vendor seemed reasonable
• The interface was much better than ours
• It was free USG licenses already

11
The Stuff Hits the Fan

• Deployment delayed
• Reliant upon others now
• Additional functionality came months/years late

12
But!

• We dont have to maintain the code
• Its better for the earlier reasons
• We can focus on teaching (right! ?)

13
Whats the Point?

• Should we develop in-house?
• Should we outsource?
• Pros and cons either way!
• Stay Tuned!!!

14
Agenda

• Essentials of an E-Commerce Site
• Build vs. Buy Models
• Outsourcing Options
• Issues to Consider
• .NET
• Encryption PGP

15
E-Commerce Essentials

• Web Presence
• Catalog Display
• Shopping Cart
• Transaction Processing
• Hooks

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Web Presence

• Obviously we need a Web site!
• Clean interface is a must
• Style reflects the company
• Make the purchase easy!

17
Catalogs

• Small stores can get away with simple static Web
  pages
• But what issues are present with a large store?
• What might Best Buy want to have?

18
Complex Catalog Features

• Search
• By name, brand, upc-code, model number
• Categories for organization
• Pictures
• Features list
• Never stand in the way

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Implementing the Catalog

• Wanna keep updating Web pages each time the
  catalog changes?
• Whats a better approach?

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DB Backend to Catalogs

• Database manages catalog content
• Tracks
• Availability
• Price
• All consumer info (features, etc.)
• Pictures

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Shopping Cart

• Replace legacy on-line forms
• NUTS!
• Preview order
• Add/Remove
• View total cost
• Allow customer to proceed to checkout

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Storing Information

• Browsers are stateless
• So how do you remember who has what in their
  shopping cart?
• How do you remember customer info from
  transaction to transaction

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Transaction Processing

• What the cashier would do
• Add sales tax (if applicable)
• Discounts
• Special Promotions
• Coupons
• Gift wrapping
• Shipping
• Order Tracking (typically outsourced)

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Hooks

• Other services are typicallycoupled with
  E-commerce sites
• Credit card processing
• Legacy systems
• Database systems

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Buy vs. Build

• Is the company in the Web design/upkeep
  business?
• Stores are interested in selling their products
• Should someone else run the site?

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Costs?

• What might some of the costs be in running your
  own E-commerce site?

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Cost Analysis Essential

• What does it cost to
• Purchase hardware
• Purchase software
• Network the office
• Purchase Net connection
• Build the site
• Maintain the site
• Hire full-time, 24-7 support
• Etc.

28
Got Website?

• Why might you not want to outsource the whole
  enchilada?

WEB
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Why Not Outsource?

• Giving up some (all?) control
• Limited somewhat in offerings
• Service providers might be overselling
• Locking yourself into one-vendor solutions -
  YIKES!

30
Outsourcing Options

• Use an ISP for connection
• Run the content off of your machines
• Web Hosting
• Put it all on their machines

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Pricing

• What can you afford?
• Micro stores
• Moms Pops
• Midrange
• Enterprise

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Micro Stores

• Less than 100 items in store
• Startup Cost 2,000
• Monthly Cost 0 - 100

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Small-Scale Development

• Smaller companies
• Want to test the water
• Gross sales 100,000
• Startup Cost 2,000
• Monthly Cost 3 of sales

34
Mid-Range Stores

• Hosted on merchants machines
• Must pay for setup 30,000
• Setup machines
• Setup Web site
• Purchase connectivity
• Monthly Cost 12,000-20,000

35
Monthly Expenses?

• No less that two full time people
• 60,000/yr minimum salary benefits
• 2,000 for co-location of machine(s)
• Machine upgrades, maintenance, etc.

36
Enter the Big Dogs

• If youre doing B2B, youre going to pay
• Larger organizations
• More transactions
• More complete back-end features (hooks)

37
EnterpriseArchitecture
Catalog DB
Corporate Server
Web Server
Client
Payment Server
Banks
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Naming Is Important!

• Which is better
• www.superstickers.com
• www.yahoo.com/superstickers

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Credibility

• Users of the site must
• Feel they can trust the owner
• Find what they are looking for quickly
• Want to come back
• Enjoy the experience

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Intermission
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.NET

• New execution/runtime environment
• Common Language Runtime (CLR)
• Class library w/ out-of-the-box functionality
• .NET Framework
• Multilanguage support (VB.NET, C, C.NET,
  Python, ADA, etc.)
• Self-describing Components (language
  independence)
• Simplified deployment (multiple versions of
  components)
• Common type system (int, currency, double,
  string, array, etc.)

42
Managed Code
Managed Code
CLR
Existing features mediated by CLR
New featuresonly in CLR(garbage collection)
Win 32 OS
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MSIL
VB.NET
Processor Specific Code
Microsoft Intermediate Language (MSIL)
C
JIT

C.NET
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ASP (.asp) vs. ASP.NET (.aspx)

• ASP via Internet Server API (ISAPI) extension on
  server (asp.dll)
• Slow performance (interpreted script)
• Difficult maintenance (mixed HTML script)
• Poor state management (application session
  variables, cookies, timeouts)
• Required COM components for advanced features
• ASP.NET via ISAPI (xspisapi.dll xsp.exe)
• Page caching, JIT/cached compilation
  performance
• Complete access to the entire .NET Framework

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Static vs. Dynamic Web Page Delivery
46
ASP.NET Delivery
47
Examples!
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Encryption

• Project 2 Due on Thurs.
• Cryptography Basics
• Symmetric vs. Asymmetric Cryptography
• Attack Methods
• PGP

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Crypto Basics

• Cryptography is thousands of years old
• Caesar Cipher based upon substitution
• AD, BE, etc.
• rot13 is a simple example of substitution
  cryptography
• V ybir vasbezngvba grpubaybtl

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Weaknesses in Older Crypto

• Patterns are easily discovered
• Letters are not randomized
• Frequency of letters (esp. vowels)
• Strength of the crypto is insufficient given
  modern computers
• Cryptoquotes for example

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Encryption Decryption
Encryption
Plaintext
Ciphertext
Crypto Algorithm
Decryption
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Symmetric Crypto

• Also known as private key cryptography
• Both sender and receiver have same key
• Problems
• Securing the key
• Number of keys O(n2) so 100 people
  communicating privately would need 10000 keys!

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Symmetric Key Infrastructure
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Asymmetric Crypto

• Also known as public key cryptography
• Sender and receiver have different keys
• Each has a public key and a private key
• Public keys are distributed via a KDC
• This scheme requires O(n) key pairs

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Asymmetric Key Infrastructure
KDC
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Public Key Cyrpto
Plain text
Encryptionwith Public KeyReceiver
Cipher text
Plain text
Decryptionwith Private KeyReceiver
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How Public Key Crypto Works

• You get my public key from the KDC
• You encode a message to me using my public key
• Only my private key can unlock this
• I receive the message
• I decode it using my private key (that only I
  have)
• I can then read the message

58
Public Key Infrastructure

• Requires validation of keys
• Thus certificate authorities
• Public key certificate contains
• ID
• Identifying information (name, e-mail)
• Date created
• Certifying authorities (their signatures)

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Public Key Encryption
Encrypted with Bobs Public Key
Encrypted with Alices Public Key
Alice
Bob
Message is Garbageto Third Party
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Attack Methods

• Brute Force
• Requires recognition of plaintext
• Key length determines strength
• Cryptanalysis
• Mathematical attack
• Faults in system
• Hack into creator of the key pair

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Attack Methods (cont)

• Factoring Attacks
• Security of asymmetric crypto resides in large
  number theory
• Its easy to generate a large composite number
  (multiply two large primes)
• But its (thought) difficult to factor these

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Mathematical Underpinnings

• Pick two large primes
• P Q
• Pick another large number (e) which does not have
  common factors with (P-1)(Q-1)
• Public key PxQ e
• Private key e-1 mod ((p-1)(q-1))

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Trap Door Theory

• Easy to create private key
• Difficult to reconstruct it
• Its easy to create the large number N
• But its difficult to factor it into P Q

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An Example

• Took seconds to generate N 114,381,625,757,888,8
  67,669,235,779,976,146,612,010,218,296,721,242,362
  ,562,561,842,935,706,935,245,733,897,830,597,123,5
  63,958,705,058,989,075,147,599,290,026,879,543,541
  (RSA-129, 1977)
• But can you find the two primes P Q such that
  PxQN?

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In Case You are Wondering

• After 17 years, it took 8 computer months and
  over 1600 computers working worldwide
• P3,490,529,510,847,650,949,147,849,619,903,898,13
  3,417,764,638,493,387,843,990,820,577
• Q32,769,132,993,266,709,549,961,988,190,834,461,4
  13,177,642,967,992,942,539,798,288,533
• And this was only a 429-bit key modern crypto
  uses a key which is 2048 bits long (5 times as
  long) which would require MUCH more time to
  decrypt (about a million times more)

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Publish or Perish?

• Should crypto algorithms be made public?
• Isnt the secrecy of the algorithm beneficial to
  security?
• How about a peer review process?

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False Encryption
Falsely Encrypted
Falsely Encrypted
Alice
Bob
Carol
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Current Technologies

• S/Mime - encrypted e-mail
• SSL - secure sockets layer for bi-directional
  communication (web)
• SET - secure credit card purchasing such that
  merchant doesnt see card
• SSH - secure shell like Telnet (putty)

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PKI Digital Signatures
Plain text
Encryption of MDFwith Private KeySender
Plain text
Decryption of MDFwith Public KeySender
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PGP

• Invented by Phil Zimmerman
• Originally released in 1991
• Used the RSA algorithm w/ legal issues
• Now it uses IDEA, CAST, and TripleDES
• Allows for variable crypto strengths

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Key Strength

• Presumably, the larger the key, the harder the
  crypto is to crack
• Why not just make the key 100,000 bits or more?

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Do Project 2 PGPHave a Great (Safe) Holiday!
FIN
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Have a Nice Long Weekend!
FIN