1. A Fast Data Protection Technique for Mobile Agents to Avoid Attacks in Malicious Hosts Jesús Arturo Pérez Díaz Darío Álvarez Gutiérrez Department of Informatics University of Oviedo Oviedo, Asturias, Spain Presenter: Chin-chi Lo

2. Outline A Secure Mobile Agent System Traditional Techniques Encryption Algorithm using Bitmaps & XOR Limitations & Conclusion

3. A Secure Mobile Agent System Protection of the agent system against attacks from mobile agents. Protection of the agent against agents. Protection of information transmission between agent servers against unauthorized third parties. Protection of the agent against malicious agent systems.

4. Traditional Techniques Public key cryptography Digital Signatures Implementing Secure Channel Ex: SSL, TLS All of the above are too complex and almost unfeasible in terms of performance.

5. Data Encryption using Bitmaps & the XOR Operation Bitmaps A random number expressed as a bitmap in a row of a matrix carried by an agent and known only to the source server. XOR Applying XOR operation between data and a random number.

6. Data Area of the Mobile Agent

7. Fields HostID: identifier of a server. CW: codeword, used to rotate the data before applying the encryption function. CRC: verifying if the data is altered. The initial value is binary 0 s.

8. Encryption Algorithm 1. The remote server creates a record with the same fields. 2. The host ID, data to be encrypted in 128-bit blocks form and a generated random CW are put into the record. 3. is rotated to the left,where

9. Encryption Algorithm (Cont.) 4. Before applying the (3.), the CW is rotated to the right.(7 most-significant bits of CW) Thus, each is not always the same.

10. Encryption Algorithm (Cont.) 5. The original CW is restored into the corresponding field of the register in order to retrieve the original information using the inverse algorithm in the source server. 6. Computing CRC. 7. The corresponding original bitmap is XOR ed with generated data. 8. The counter indicating the number of lines used in the matrix is incremented.

11. Limitations of the Method Does not prevent the possible alternation of data from malicious hosts The current server could see and copy the still available rows. The two cooperating malicious servers. There is a fixed maximum number of data that can be protected.

12. Conclusion That is a trade-off between performance and security.