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