Doo Ho Choi

Secure session key exchange for mobile IP low latency handoffs

Mobile IP Low Latency Handoffs[1] allow greater support for real-time services on a Mobile IPv4 network by minimising the period of time when a mobile node is unable to send or receive IP packets due to the delay in the Mobile IP Registration process. However, on Mobile IP network with AAA servers that are capable of performing Authentication, Authorization, and Accounting(AAA) services, every Regional Registration has to be traversed to the home network to achieve new session keys, that are distributed by home AAA server, for a new Mobile IP session. This communication delay is the time taken to reauthenticate the mobile node and to traverse between foreign and home network even if the mobile node has been previously authorized to old foreign agent. In order to reduce these extra time overheads, we present a method that performs Low Latency Handoff without requiring further involvement by home AAA server. The method re-uses the previously assigned session keys. To provide the confidentiality of session keys in the phase of key exchange between old FA and new FA, it uses a key sharing method with a trusted third party. The proposed method allows the mobile node to perform Low Latency Handoff with fast as well as secure operation.

A secure mobile IP authentication based on identification protocol

Mobile IP, which was designed at the working group of IETF, intended to enable nodes to move from one IP subnet to another. That is, it can support node mobility across heterogeneous networks. For this mobility support, a mobile node (MN) must achieve registration at a home agent (HA) when the MN is away from home. In this article, we propose a mobile IP authentication that is based on an identification scheme using a one-way function. It ensures a secure mobile IP authentication against replay attack and man-in-the-middle attack. Furthermore, its implementation is expected to be efficient, since it does not use any public key cryptography operations.

New efficient batch verification for an identity-based signature scheme

Batch verification is a method to verify multiple digital signatures at a batch in time less than total individual verification time. Batch verification for an identity-based signature scheme IBS is attractive because a short public identity such as an e-mail address can be used as a verification key.

Privacy protection for secure mobile RFID service

Widespread deployment of radio frequency identification (RFID) tags may create new threats to user privacy due to the automated tracking capability. Recently, RFID technology shows a convergence tendency. RFID reader is contained in a mobile phone. User privacy problem is a prior consideration for mobile RFID service deployment, since most mobile RFID service scenario is based on end-user service. In this paper, we propose a new solution for user privacy protection, which is a modification of EPC Class-1 Generation-2 protocol. Furthermore, we introduce a privacy protection scenario for mobile RFID service using this proposed scheme.

Session Key Exchange Based on Dynamic Security Association for Mobile IP Fast Handoff

For Low Latency Handoffs(LLH) [1] to be fast and effective, the Mobile IP session keys distributed by home AAA(Authentication, Authorization, and Accounting) server should be reused [2]. This can decrease the number of signaling messages to the home network, and reduce the signaling delay when a mobile node moves from one foreign agent to another, within the same visited domain. To reuse the session keys in a secure fashion, we present a method that performs the LLH without requiring further involvement by home AAA server. To prevent session stealing attack, the method provides the confidentiality and integrity of session keys in the phase of key exchange between old foreign agent and new foreign agent by using Diffie-Hellman key agreement. It allows the mobile node to perform LLH with fast as well as secure operation.

A Solution for Reducing Redistribution Costs of HAIL

The Proof of Retrievability (PoR) is a useful tool for securing data by monitoring the retrievability of a file stored in remote servers. But they are not secure if the full data stored in the storage server is attacked. HAIL has been proposed to solve this problem. It enables a client to verify that files stored in independent storage servers are intact and retrievable. If some servers are attacked, a client can reconstruct the original data using the data stored in remaining servers. Unfortunately, in HAIL, expensive redistribution costs occur if we need to reconstruct the original data, which was not considered in existing works. In this paper, we propose a solution for reducing redistribution costs by grouping file segments and applying HAIL to each group. It is unnecessary for clients to download all files in all servers when some files stored in a specific server are corrupted. Finally, we analyze the performance of our scheme.

Data Preprocessor for Order Preserving Encryption

Sensitive data such as personal telephone number, address, social security number at database is prevented to access by SQL search query. In order to prevent security problems it needs to encrypt database. Order preserving encryption (OPE) is a method of encrypting data so that its possible to make efficient inequality comparisons on the encrypted items without decrypting them. OPE data of database is available to make index without decryption. In this paper, the data preprocessor by reducing plaintext range, the performance of OPE is increased and sensitive data are protected at database.

A fault-resistant implementation of AES using differential bytes between input and output

Pervasive computing environments focus on integrating computing and communications with the surrounding physical environment. As a potential threat in the physical environment, fault attacks using the injection of practical faults have been introduced for extracting secret keys stored in low-cost devices. In particular, the advanced encryption standard (AES) has been broken by various fault attacks, and satisfactory countermeasures have yet to be introduced. This paper proposes a new countermeasure that can prevent fault attacks by verifying differential bytes of input and output in the encryption process and the key expansion process, respectively. The results of computer simulations and fault injection experiments verify that the proposed countermeasure against fault attacks outperforms existing countermeasures in terms of fault detection and efficiency.

Efficient key detection method in the correlation electromagnetic analysis using peak selection algorithm

A side channel analysis is a very efficient attack against small devices such as smart cards and wireless sensor nodes. In this paper, we propose an efficient key detection method using a peak selection algorithm in order to find the advanced encryption standard secret key from electromagnetic signals. The proposed method is applied to a correlation electromagnetic analysis (CEMA) attack against a wireless sensor node. Our approach results in increase in the correlation coefficient in comparison with the general CEMA. The experimental results show that the proposed method can efficiently and reliably uncover the entire 128-bit key with a small number of traces, whereas some extant methods can reveal only partial subkeys by using a large number of traces in the same conditions.