Paper: Testing Randomness in Ciphertext of Block-Ciphers Using DieHard Tests

One of the important aspects of the security of block ciphers is the randomness of the cipher text. One criterion used to evaluate the Advanced Encryption Standard (AES) candidate algorithms was their demonstrated suitability as random number generators.
In this paper, we introduced a new approach to interpret the results of tests of randomness. This approach relies on using DieHard battery of tests which was designed originally to test the randomness of Random Number Generators (RNGs). The proposed approach was used to test the randomness of five types of data; plaintext, 3DES-encrypted, AES-encrypted, Serpent-encrypted, and Blowfish-encrypted. The tests resulted in 47 p-values for each type of data. This paper suggests the classification of results of DieHard tests into three areas; Safe Area, Doubt Area, and Failure Area. The resulting p-values for each data type were distributed over these areas according to the suggested ranges. The data type having more p-values in the Safe Area indicate better randomness, while the existence of many p-values in the Failure Area indicates deviation from randomness. The results of the implemented tests showed that AES- and Blowfish-encrypted data provided equal results in term of number of p-values distributed over different areas. The AES and Blowfish results were slightly better than Serpent-encrypted data while 3DES encrypted data had more p-values in the Doubt Area.

Citation Information:

Mohammed M. Alani, Testing Randomness in Ciphertext of Block-Ciphers Using DieHard Tests, International Journal of Computer Science and Network Security (IJCSNS), Vol.10, No.4, April 2010, pp. 53-57.

Paper: DES96 – Improved DES Security


The Data Encryption Standard (DES) has shown noticeable signs of aging during the last two decades. In this paper we develop a system that is a DES-variant with more resistance towards the possible attacks against DES. The developed system has a sub-key generation algorithm that is completely different from the original DES.
The developed system uses 84-bit initial key instead of the 56-bit key originally used. It has substitution boxes inside the key generation algorithm and mod2 additions. The choice of arrangement of substitution boxes in the main algorithm for each round is sub-key dependent. The result of the design is a DES-variant cryptographic system that has higher resistance against brute-force attack, differential cryptanalysis, and linear cryptanalysis. The proposed system design also cancelled the weak-keys and complement keys properties of the DES.

Index Terms – data encryption standard, encryption, cryptanalysis.

Citation Information:

Mohammed M. Alani, DES96 – Improved DES Security,  Proceedings of the 7th IEEE International Multi-Conference on Systems, Signals and Devices (SSD’10) , Amman, Jordan. June 2010. (IEEEXplore).

Paper: Development of a VoIP Security System Based on H.323 Protocol

In this thesis a secure IP-Telephony framework is proposed. This framework relies on H.323 and covers two of the most important weaknesses that were in the original H.323 and were not covered in an efficient and easily implementable way. These two weaknesses are secrecy of voice data traveling from one EndPoint to another, and authentication between GateKeepers when calls made are Inter-GateKeeper calls. In the suggested framework, Advanced Encryption Standard and HMAC-SHA1-96 were used to overcome the weak points of the original H.323.
The suggested framework was implemented and tested and has proved strength over most popular IP-Telephony attacks and provided acceptable quality of service as compared to other solutions of the H.323 security loopholes. The implementation was tested for two different scenarios; calls placed on EndPoints laying in the same local area network, and calls made over the Internet with EndPoints laying in different zones.
For the local area network calls, the delay was 61 milliseconds, and the jitter was 8 millisecond, with an average loss of 0.93%. For the Internet-separated EndPoints, the delay was 265 milliseconds, and the jitter was 41 milliseconds, with an average loss of 1.22%. These values were calculated for 1000 calls.
The implementation environment included Asterisk software as the GateKeeper software, and JCPPhone as the EndPoints software. The Asterisk version used was AsteriskNOW beta5-x86. It was installed on Linux servers.
The proposed system has shown more resistance towards the most common three IP-Telephony attacks; toll fraud, eavesdropping, and denial of service. The features of the proposed system were compared with the original H.323 set, Session Initiation Protocol, and H.235 Annex D.

Citation Information:

Mohammed M. Alani,  “Development of a VoIP Security System Based on H.323 Protocol”, PhD Thesis, Computer Engineering Department, College of Engineering, Nahrain University, May, 2007.


Mohammed M. Alani,  “Development of a VoIP Security System Based on H.323 Protocol”, PhD Thesis, Computer Engineering Department, College of Engineering, Nahrain University, Baghdad, Iraq. May, 2007.

Paper: Design of H.323 Secure IP-Telephony Framework

The paper is aimed to provide a secure IP-Telephony system based on H.323 set of protocols. H.323 is a standard that specifies the components and procedures that provide multimedia communication services—real-time audio, video, and data communications—over packet networks, including Internet protocol (IP)–based networks. H.323 is part of a family of ITU—T recommendations called H.32x that provides multimedia communication services over a variety of networks. From the security aspect, H.323 provides a scheme for authentication between the End Point (EP) and the GateKeeper (GK). However, the authentication between EPs lying on different GKs needs to be considered. Thus, the paper shows a proposed model and implementation with the evaluation of such authentication process. It also provides secrecy for certain users that require such a service. These have been provided by providing authentication for EPs laying on different GKs, as well as providing encryption for the voice data traveling between EPs laying on same GK or different GKs.

Keywords: Computer network, VoIP, IP-Telephony, H.323, and VoIP security.

Citation Information:

Siddeeq Y. Ameen, Fawzi Alnaima, and Mohammed M. Alani, Design of H.323 Secure IP-Telephony Framework, published in The 6th International Philadelphia Engineering Conference On Computational Aspects and Their Applications in Electrical Engineering, Philadelphia University, Amman, Jordan, September, 2006.