Resource Sharing of Portable Computers Using Wireless Communication
By Christine Meyer
Outline• Routing Protocols
• Load Balancing Techniques
• Cluster Computing Software
• Wireless Security Attacks
• Conclusion
Wireless Adhoc Mode
Peer-to-Peer Communication
Wireless Infrastructure Mode
Communication through Access Point
Direct Sequence Spread Spectrum (DSSS)
Wireless Range
Routing Protocols
• Dynamic Source Routing (DSR)
• Destination Sequence Distance Vector (DSDV)
• Temporary-Ordered Routing Algorithm (TORA) • Ad Hoc On-Demand Distance Vector (AODV)
Comparison of Routing Protocols
Packet Delivery Ratio Routing Overhead
Diffusive Load Balancing on Domain
Windows Management Instrumentation
Namespace: root\WMI for signal strength root\CIMV2 for LB information
Cluster Computing Software
Resource Manager
Server
Job Manager Client Manager
Application
ClientDisplay
Manager
Wireless Network Display
Client to Server Routing 1
ServerClient A
Client B
Routing A
Routing A
Client to Server Routing 2
ServerClient A
Client B
Routing A, B
Routing A, B
Routing to Server
Encryption using Javaimport javax.crypto.*;import javax.crypto.spec.*;import java.security.*;
SecretKey key = KeyGenerator.getInstance("DESede").generateKey();byte[] keyBytes = new byte[] {107,127,4,115,-23,55,93,47, -36,-105, -26, 4, 38, -83,-29, 62, 107,127,4,115,-23,55,93,47}; try { SecretKey key = new SecretKeySpec(keyBytes, "DESede"); Cipher ecipher = Cipher.getInstance("DESede"); ecipher.init(Cipher.ENCRYPT_MODE, key); // Seal (encrypt) the object s1 = new SealedObject(mat1, ecipher); s2 = new SealedObject(mat2, ecipher); } catch (Exception e) {}
Decryption with Java byte[] keyBytes = new byte[] {107,127,4,115,-23,55,93,47, -36,-105, -26, 4, 38, -83,-29, 62, 107,127,4,115,-23,55,93,47}; try { SecretKey key = new SecretKeySpec(keyBytes, "DESede"); Cipher dcipher = Cipher.getInstance("DESede"); dcipher.init(Cipher.DECRYPT_MODE, key); // Unseal (decrypt) the class a = (Matrix)s1.getObject(dcipher); b = (Matrix)s2.getObject(dcipher); } catch (Exception e) {}
Java Transformation String• Algorithm AES, Blowfish, DES, DESede, RSA, RC2, RC4, RC5
• Mode None, CBC (Cipher Block Chaining), CFB (Cipher Feedback Mode), ECB (Electronic Codebook), OFB (Output Feedback Mode), PCBC (Propagating Cipher Block Chaining)
• Padding No Padding, PKCS5Padding SSL3Padding
Default: DES/CBC/PKCS5Padding (64 bits to 128 bits)
DES 64 bits to 64 bits:transform = "DES/ECB/NoPadding“
Passive attacks to decrypt traffic
Destination
Eavesdropper
Packet 1 XOR Packet 2= Plaintext
Access Point
Active attack to inject new traffic
Destination
Eavesdropper
RC4(X) XOR X XOR Y= RC4(Y)
Access Point
Active attacks to decrypt traffic
Eavesdropper
Access Point Internet Eavesdropper’sComputerEncrypted
Message
DecryptedMessage
DecryptedMessage
Table based Attack
Destination
Eavesdropper
Access Point
Table of IV andKey Streams
WPA Denial of Service Attack
WPA can shutdown the system if it receives two failed packets within a one-second period
Wi-Fi Encryption Fix Not Perfecthttp://www.wired.com/news/business/0,1367,56350,00.html
Conclusion• It is possible to improve performance through resource sharing of portable computers
• In the future, the transfer rate for wireless will be greater therefore reducing transfer time
• Security is provided for access points but not for ad-hoc mode
• Encryption is possible through Java with a small overhead factor