Wireless Communications

National Institute of Standards and Technology における超伝導研究及び生活

High peak-to-average power ratio of the transmit signal is a major drawback of multicarrier transmission such as OFDM or DMT. This article describes some of the important PAPR reduction techniques for multicarrier transmission including amplitude clipping and filtering, coding, partial transmit sequence, selected mapping, interleaving, tone reservation, tone injection, and active constellation extension. Also, we make some remarks on the criteria for PAPR reduction technique selection and briefly address the problem of PAPR reduction in OFDMA and MIMO-OFDM.

An overview of peak-to-average power ratio reduction techniques for multicarrier transmission

This paper introduces and makes concrete the concept of certificateless public key cryptography (CL-PKC), a model for the use of public key cryptography which avoids the inherent escrow of identity-based cryptography and yet which does not require certificates to guarantee the authenticity of public keys The lack of certificates and the presence of an adversary who has access to a master key necessitates the careful development of a new security model We focus on certificateless public key encryption (CL-PKE), showing that a concrete pairing-based CL-PKE scheme is secure provided that an underlying problem closely related to the Bilinear Diffie-Hellman Problem is hard

/pdf/certificateless-public-key-cryptography-3qm3rm01ss.pdf

Certificateless Public Key Cryptography

This paper introduces and makes concrete the concept of certificateless public key cryptography (CL-PKC), a model for the use of public key cryptography which avoids the inherent escrow of identity-based cryptography and yet which does not require certificates to guarantee the authenticity of public keys. The lack of certificates and the presence of an adversary who has access to a master key necessitates the careful development of a new security model. We focus on certificateless public key encryption (CL-PKE), showing that a concrete pairing-based CL-PKE scheme is secure provided that an underlying problem closely related to the Bilinear Diffie-Hellman Problem is hard.

Certificateless public key cryptography

Pairings for cryptographers

Controlling the peak-to-mean envelope power ratio (PMEPR) of orthogonal frequency-division multiplexed (OFDM) transmissions is a notoriously difficult problem, though one which is of vital importance for the practical application of OFDM in low-cost applications The utility of Golay complementary sequences in solving this problem has been recognized for some time In this paper, a powerful theory linking Golay complementary sets of polyphase sequences and Reed-Muller codes is developed Our main result shows that any second-order coset of a q-ary generalization of the first order Reed-Muller code can be partitioned into Golay complementary sets whose size depends only on a single parameter that is easily computed from a graph associated with the coset As a first consequence, recent results of Davis and Jedwab (see Electron Lett, vol33, p267-8, 1997) on Golay pairs, as well as earlier constructions of Golay (1949, 1951, 1961), Budisin (1990) and Sivaswamy (1978) are shown to arise as special cases of a unified theory for Golay complementary sets As a second consequence, the main result directly yields bounds on the PMEPRs of codes formed from selected cosets of the generalized first order Reed-Muller code These codes enjoy efficient encoding, good error-correcting capability, and tightly controlled PMEPR, and significantly extend the range of coding options for applications of OFDM using small numbers of carriers

https://www.hpl.hp.com/techreports/98/HPL-98-57R1.pdf

Generalised Reed-Muller codes and power control in OFDM modulation

The Transport Layer Security (TLS) protocol aims to provide confidentiality and integrity of data in transit across untrusted networks. TLS has become the de facto secure protocol of choice for Internet and mobile applications. DTLS is a variant of TLS that is growing in importance. In this paper, we present distinguishing and plaintext recovery attacks against TLS and DTLS. The attacks are based on a delicate timing analysis of decryption processing in the two protocols. We include experimental results demonstrating the feasibility of the attacks in realistic network environments for several different implementations of TLS and DTLS, including the leading OpenSSL implementations. We provide countermeasures for the attacks. Finally, we discuss the wider implications of our attacks for the cryptographic design used by TLS and DTLS.

/pdf/lucky-thirteen-breaking-the-tls-and-dtls-record-protocols-3npri4yio0.pdf

Kenneth G. Paterson

Papers

Certificateless Public Key Cryptography

Certificateless public key cryptography

Pairings for cryptographers

Generalised Reed-Muller codes and power control in OFDM modulation

Lucky Thirteen: Breaking the TLS and DTLS Record Protocols