Download presentation
Presentation is loading. Please wait.
Published byArnold Spencer Modified over 8 years ago
1
CS4241: Webware Class 25: A Few Short Topics Web Security 1 Copyright 2004-2010, Michael J. Ciaraldi
2
2 Favicon
3
3 An icon for a Web site, displayed o On the address bar. o With the bookmark. Supported by many browsers. o Internet Explorer o Mozilla / Firefox o Opera o Not Lynx For an intro: o http://www.thesitewizard.com/archive/favicon.shtml http://www.thesitewizard.com/archive/favicon.shtml
4
4 Using Favicon Browser looks for image file favicon.ico o First in same directory as Web page. o Next in site’s home directory. Can also request a specific icon. o Put this tag in the of the page:
5
5 Making a Favicon Must be an icon (.ico) file. o 16 x 16 pixels for menu. o 32 x 32 pixels for “large icon” view. Will be scaled if necessary. o Both can be in the same file. Many free icon editors. o http://www.thefreecountry.com/programming/ resourceeditors.shtml http://www.thefreecountry.com/programming/ resourceeditors.shtml o I used IconSuite.
6
6 Opening Other Pages & Passing Data to Them
7
7 Opening Other Pages Tutorial: o http://www.htmlgoodies.com/beyond/ja vascript/article.php/3471221/So-You- Want-To-Open-A-Window-Huh.htm http://www.htmlgoodies.com/beyond/ja vascript/article.php/3471221/So-You- Want-To-Open-A-Window-Huh.htm o Use window.open(…) o You can create objects and functions, then pass them to the JavaScript in the other window.
8
8 Passing Data to Other Pages An interesting example: o http://www.mattkruse.com/javascript/c alendarpopup http://www.mattkruse.com/javascript/c alendarpopup o Pops up a calendar in a new window. o Selected date returned to original window. var cal1 = new CalendarPopup(); cal1.select(inputObject, anchorname, dateformat);
9
9 Security
10
10 Security Need for Security Where security is implemented Encryption Network security Virtual Private Networks
11
11 Need for Security Isn’t it obvious? Deliberate and accidental threats. Consequences: o Lost or altered information. o Revealed information. o Financial loss. o Embarrassment.
12
12 Where is Security Implemented? Within servers o Standard stuff LAN / Wireless o Access control o Encryption Along the Internet o Encryption
13
13 Network Security Encryption (communications) Authentication. Access control.
14
14 Access Control LAN o MAC address registration o User authentication Wireless o As above o WEP / WPA
15
15 Encryption Encryption algorithms o DES, Triple-DES o RSA o AES Key length Key systems
16
16 Key Systems Public vs. Private Symmetric vs. Asymmetric Shared vs. Public Public
17
17 Shared Key One key shared between sender and receiver. How to share it securely? How to store it securely? How to manage multiple communication partners?
18
18 Public / Private Key Every entity has two keys, public and private. Both needed to encrypt / decrypt. Neither can be derived from the other. PKI = Public Key Infrastructure
19
19 Using Public Key System To send: o Encrypt with the recipient’s public key. o Recipient decrypts with his private key. Alternative: o Encrypt with sender’s private key. o Recipient decrypts with sender’s public key. Or both! Which one guarantees what?
20
20 Authentication Shared key Public / private Message digest / digital signature o Faster than complete encryption. Are you sure public keys are valid? Digital certificates o Hold public keys. o Can you trust them? o Can be revoked.
21
21 Network Communications Security Physical IPSEC SSL
22
22 Physical Security Pretty hard to be absolutely sure. o Wiretap o Hubs vs. Switches o Fiber optic Extreme measures.
23
23 IPSEC Based on PKI. Must be in the kernel. Standard in IPv6. Optional in IPv4. Adds headers, wraps packets. Provides encryption and authentication. Can disrupt traffic shaping.
24
24 IPSEC Based on PKI. Must be in the kernel. Standard in IPv6. Optional in IPv4. Adds headers, wraps packets. Provides encryption and authentication. Can disrupt traffic shaping.
25
25 SSL Secure Socket Layer Based on PKI / Certificates Operates above the OS. Why? o In the Web server o In the client
26
26 VPN Virtual Private Network Can be based on public or private keys. Intercepts and tunnels packets based on address. Can extend the LAN.
27
And Then There’s Cyberwar Easiest: o DOS & DDOS. Domain server hijacking. Hijacking traffic by changing routing tables. 27
28
Next Times Tuesday: Final Exam Thursday: Future of the Web 28
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.