With the establishment of the AES the need for new block ciphers has been greatly diminished; for almost all block cipher applications the AES is an excellent and preferred choice. However, despite recent implementation advances, the AES is not suitable for extremely constrained environments such as RFID tags and sensor networks. In this paper we describe an ultra-lightweight block cipher, present . Both security and hardware efficiency have been equally important during the design of the cipher and at 1570 GE, the hardware requirements for present are competitive with today's leading compact stream ciphers.

/pdf/present-an-ultra-lightweight-block-cipher-33ym33ql7r.pdf

PRESENT: An Ultra-Lightweight Block Cipher

We present a new block cipher LED. While dedicated to compact hardware implementation, and offering the smallest silicon footprint among comparable block ciphers, the cipher has been designed to simultaneously tackle three additional goals. First, we explore the role of an ultra-light (in fact non-existent) key schedule. Second, we consider the resistance of ciphers, and LED in particular, to related-key attacks: we are able to derive simple yet interesting AES-like security proofs for LED regarding related- or single-key attacks. And third, while we provide a block cipher that is very compact in hardware, we aim to maintain a reasonable performance profile for software implementation.

The LED block cipher

In this paper we propose a new family of very efficient hardware oriented block ciphers. The family contains six block ciphers divided into two flavors. All block ciphers share the 80-bit key size and security level. The first flavor, KATAN, is composed of three block ciphers, with 32, 48, or 64-bit block size. The second flavor, KTANTAN, contains the other three ciphers with the same block sizes, and is more compact in hardware, as the key is burnt into the device (and cannot be changed).

The smallest cipher of the entire family, KTANTAN32, can be implemented in 462 GE while achieving encryption speed of 12.5 KBit/sec (at 100 KHz). KTANTAN48, which is the version we recommend for RFID tags uses 588 GE, whereas KATAN64, the largest and most flexible candidate of the family, uses 1054 GE and has a throughput of 25.1 Kbit/sec (at 100 KHz).

/pdf/katan-and-ktantan-a-family-of-small-and-efficient-hardware-1nbl4htw1x.pdf

KATAN and KTANTAN -- A Family of Small and Efficient Hardware-Oriented Block Ciphers

This paper presents a block cipher that is optimized with respect to latency when implemented in hardware. Such ciphers are desirable for many future pervasive applications with real-time security needs. Our cipher, named PRINCE, allows encryption of data within one clock cycle with a very competitive chip area compared to known solutions. The fully unrolled fashion in which such algorithms need to be implemented calls for innovative design choices. The number of rounds must be moderate and rounds must have short delays in hardware. At the same time, the traditional need that a cipher has to be iterative with very similar round functions disappears, an observation that increases the design space for the algorithm. An important further requirement is that realizing decryption and encryption results in minimum additional costs. PRINCE is designed in such a way that the overhead for decryption on top of encryption is negligible. More precisely for our cipher it holds that decryption for one key corresponds to encryption with a related key. This property we refer to as α-reflection is of independent interest and we prove its soundness against generic attacks.

/pdf/prince-a-low-latency-block-cipher-for-pervasive-computing-3rf9hqsh69.pdf

PRINCE: a low-latency block cipher for pervasive computing applications

In this paper, we propose a new block cipher HIGHT with 64-bit block length and 128-bit key length. It provides low-resource hardware implementation, which is proper to ubiquitous computing device such as a sensor in USN or a RFID tag. HIGHT does not only consist of simple operations to be ultra-light but also has enough security as a good encryption algorithm. Our hardware implementation of HIGHT requires 3048 gates on 0.25 μm technology.

/pdf/hight-a-new-block-cipher-suitable-for-low-resource-device-2vmhkebofj.pdf

HIGHT: a new block cipher suitable for low-resource device

The traceability is one of the core requirements for group signature schemes. Group signature schemes based on the bilinear mapping were proposed. The bilinearity of a bilinear mapping allows an efficient signature scheme verification for signature schemes based on the discrete logarithm type problem. But the bilinearity of a bilinear mapping can be an attack point with respect to the traceability for group signature schemes when it is designed in such a way that the linearity can be preserved. We show that Cheng-Zhu-Qiu-Wang's group signature schemes (X. Chen et al., 2005) based on bilinear mapping have no traceability property due to their improper use of a bilinear mapping in their signature generation and verification step. We also propose security enhanced group signature schemes for both of mini group signature scheme and improved group signature scheme of Cheng-Zhu-Qiu-Wang's

Untraceability of Group Signature Schemes based on Bilinear Mapping and Their Improvement

Mobile networking, mobile systems and applications and ubiquitous computing infrastructures are of strongly growing importance in the IT sector in general, and for the parallel and distributed computing community. Particularly, when an signed(authenticated) information of multi-node is aggregated in ubiquitous sensor networks, the number of the signing information is very small. Thus, signature scheme which signs information has strong unforgeability. In 2005 Yu and Chen proposed threshold signature scheme [12]. Their scheme has a high efficiency. But, their scheme is not suitable for ubiquitous sensor networks because their scheme has no strong unforgeability. In this paper, we modify their scheme so that modified scheme is suitable for ubiquitous sensor networks. Also, our scheme has a good efficiency, and a smaller secret key than other cryptosystems with a similar security level.

Hyun Kim

Papers

HIGHT: a new block cipher suitable for low-resource device

Untraceability of Group Signature Schemes based on Bilinear Mapping and Their Improvement

An information aggregation scheme of multi-node in ubiquitous sensor networks