Signal Processing for Security
Members:
Bariş Coşkun
Mehmet Ozgur Depren
Murat Topallar
İmran Ergüler
Alper Karahisar
Watermarking and Steganography
Steganalysis and Watermarking
Researchers: Ismail Avcibas, Hamza Ozer, Ahmet Bastug,
Bulent Sankur
Description: We have developed schemes for the automatic
detection of the presence of hidden messages (the steganalysis
problem) in image and audio documents. We have also investigated the
contribution of error correcting codes in enhancing the data hiding capacity of
images.
Hash function
Researchers: Hamza
Ozer, Baris Coskun, Bulent Sankur
Description: Robust hash functions, focused on content of
the document, for both audio and video documents, are developed. The hash
output can be used both for database searching purposes as well as watermarking
and authentication check.
Publications:
Bastug, B. Sankur, Improving
the Payload of Watermarking Channels via LDPC Coding, IEEE Signal Proc.
Letters, 11(2), 90-92, February 2004.
O. Ekici, B. Sankur, B. Coskun,
U. Naci, M. Akcay, Comparative Assessment of Semifragile
Watermarking Methods, Journal of
Electronic Imaging, 13(1), 209-216, January 2004.
Avcibas, B. Sankur, N. Memon, Steganalysis of Watermarking and Steganographic
Techniques Using Image Quality Metrics, IEEE Trans. on Image Processing,
12(2), 21-229, 2003.
B. Coskun, B. Sankur, Robust
Video Hash Extraction, EUSIPCO’2004: European Conf. On
Signal Processing,
H. Ozer, B. Sankur,
Avcibas, S. Bayram, N. Memon,
B. Sankur, M. Ramkumar, A Classifier
Design For Detecting Image Manipulations, ICIP’2004:
Intern. Conference on Image Processing, Sept. 2004,
S. Baudry, J.F. Delaigle, B. Sankur, B. Macq, H. Maitre, Analyses
of Error Correction Strategies for Typical Communication Channels in
Watermarking, Signal Processing, 81(6), 1239-1250, June 2001 .
H. Ozer, I. Avcibas, B. Sankur, N. Memon, Steganalysis of Audio Based on Audio Quality Metrics, SPIE Electronic Imaging Conf. On Security and Watermarking of Multimedia Contents, Jan. 20-24,
S. Zinger, Z. Jin, H. Maitre, B. Sankur, Optimization
of Watermarking Performances Using Error Correcting Codes and Repetition,
CMS’2001: Communications and Multimedia Security, May 2001, 229-240, Darmsadt, Germany.
C. Coatrieux, H.
Maitre, B. Sankur, Y. Rolland, R. Collorec,
Relevance
of Watermarking in Medical Imaging, 2000 IEEE EMBS Conf. On
Information Technology Applications in Biomedicine, 250-255, Nov. 2000,
Intrusion Detection
Researchers: E. Anarım,
M.O. Depren, M. Topallar,
K. Ciliz.
Description:
We introduce a
hybrid Intrusion Detection System (IDS) architecture utilizing both anomaly and
misuse detection approaches. The proposed anomaly detection module uses
Self-Organizing Map (SOM)
structure to model normal behavior. The misuse detection module uses J.48 decision tree
algorithm to classify various types of attacks. A rule-based Decision Support System (DSS) is
developed for interpreting the results of both anomaly and misuse detection
modules.
Publications:
M.Ö. Depren,
M. Topallar, E. Anarım and K.
Cılız, “Network Based Anomaly Intrusion Detection using Self
Organizing Maps (SOM)s”, Proceedings of
IEEE SIU 2004 (12th National
Conference on Signal Processing and Applications), pp. 76-79,
M. Topallar, M.Ö. Depren, E.
Anarım and K. Cılız,
“Host Based Intrusion Detection by Monitoring Windows Registry Accesses”, Proceedings of IEEE SIU
2004 (12th National Conference on Signal Processing and Applications),
pp.728-731, Kuşadası, Turkey, 18-20 May, 2004.
Cryptoanalysis
Researchers:
Emin Anarim, İmran Ergüler
Description: We first show that combination of Oechslin’s method with the rainbow chain model for block
ciphers and Biryukov’s method of applying
pre-computed tables on stream ciphers improves in time-memory trade off. We
also propose a new pre-computation table, which can solve the difficulties
encountered by an attacker that faces difficulties whenever the stream
generator changes its present state in an irregular manner, for example clock
controlled generators. Our proposed
solution is based on a new pre-computation table for the case where the number
of different initial states yielding the same internal state at some time in
future and the same output sequence is very likely to be a very small integer.
Publications:
Imran Erguler, Alper Karahisar and Emin Anarim, “A Cryptanalytic
Time-Memory Trade-Off for Stream Ciphers”, 5th International Conference on
Cryptology in India (Indocrypt2004), Dec. 20-22, 2004, Chennai, India,
submitted.
Imran Erguler and Emin Anarim, “A
New Pre-computational Table for Time-Memory Trade-Off Attack on Stream
Ciphers”, 5th International Conference on Cryptology in India (Indocrypt2004),
Dec. 20-22, 2004, Chennai, India, submitted.
Imran Erguler, Alper Karahisar, Emin Anarim, ”A
Time-Memory Trade-Off Attack on A5/1 GSM Stream Cipher”, IEEE Trans. Inform.
Theory,(under review),2004.