International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Next generation flight termination systems (FTSs) will use digital technologies to verify the authenticity of range safety commands by command receiver-decoders located on each vehicle. This paper will discuss the general principles behind simplex message authentication using a block encryption cipher, and presents examples for demonstration.

Darbe apžvelgiami esami duomenų šifravimo metodai, jų klasifikacija. Taip pat detaliai aprašomi keletas šifravimo algoritmų. Pagal AES šifravimo algoritmą sukuriama informacijos kodavimo programa Visual Basic kalba ir pademonstruojama keletas palyginamųjų rezultatų su jau egzistuojančiomis, analogiškomis programomis. / Data protection problem is relevant in now days living. This paper takes a review of the existing methods and programs in digital data cryptography. Also it explains AES (advanced encryption standard) method, the most trustful one and overviews software tool, that was coded and used in experiments analysing this algorithm. The new AES class, that was created in this project, is compared using few parameters with the older one, created by Microsoft. Despite the only purpose, to create a better program, the older implemented AES cipher class and it’s methods beats the new one.

In this work we study cryptanalysis one of the most current stream ciphers A5/1. The cipher is used to provide mobile communication privacy in the GSM cellular telephone standard. An essential element of the cipher A5/1 is LFSR( Linear feedback shift register) which is used in stream ciphers because it produces a sequence of bits with high periodicity, has good statistical properties and is easily analyzed using various algebraic methods. At work, we describe and implement three known-plaintext attacks on the cipher. The first two attacks are of the type Guess and Determine and the last one is correlation attack. The focus of the work is cryptanalysis by Golić, which assumes only 64 bits of plaintext. The character of implementation allows to split the work and use parallel-computing, making it possible to use the program in practice. At the end of the work we devote to correlation attack, that is considerably faster, but it assumes knowledge of the relatively large amount of plaintext.

Neste documento apresentamos uma cifra multicanal inspirada nas técnicas de telecomunicações de espalhamento espectral (Spread Spectrum), ou como também conhecido, difusão espectral, para prevenir escuta em uma rede de computadores TCP/IP. Mostramos que dividindo um texto-ilegível ciphertext em blocos de tamanho fixo e transmitindo-os aleatoriamente através de diversos canais estabelecidos entre os agentes (transmissor - receptor) é possível aumentar a complexidade da criptanálise por um suposto adversário não autorizado que esteja escutando a comunicação, dessa forma aumentando relativamente a segurança. Mostramos teoricamente que o tempo de quebra da cifra multicanal cresce em ordem fatorial ou exponencial em função do número de canais utilizados na comunicação. Além disso, adaptado a um esquema de difusão binária herdado do AES (Advanced Encryption Standard) é possível incrementar a segurança da cifra multicanal para maior resiliência contra a criptanálise diferencial. / In this work we present a multichannel cipher inspired on telecommunications Spread Spectrum techniques to prevent eavesdropping in a TCP/IP network. We show that splitting any ciphertext into fixed size blocks and sending them randomly through multiple channels established between the agents (transmitter and receiver) it is possible to increase the complexity of cryptanalysis by a supposed not authorized adversary that might be eavesdropping the communication, in this way, relatively increasing the security. We show theoretically that the brake time of multichannel cipher grows in factorial or exponential order, in function of the number of channel used in the communication. Moreover adapted to binary spread scheme inherited from AES (Advanced Encryption Standard) it is possible to increase the cipher security for more resilience against differential cryptanalysis.

<p>Stream ciphers are counted as an important part of symmetric encryption method. Their basic idea comes from One-Time-Pad cipher using XOR operator on the plain text and the key to generate the cipher. The present work brings a new idea in symmetric encryption method, which inherits stream key generation idea from synchronous stream cipher and uses division instead of xoring. The Usage of division to combine the plain text with stream key gives numerous abilities to this method that the most important one is using random factors to produce the ciphers.</p>

The relationship between authors and readers has been heavily studied in western literatures since the shift between the spoken-subject lost its privileged position to the written author. The struggle for who determines truth has formed a specific dialect that requires either the author or the reader to be silent. Since the acceptance of literary theories like the “death of the author” and “author-function,” we continue to map these concepts on to similar relationships and discourses. Hip-hop culture defies this dialect, instead, based around the concept of the cipher, hip-hop insists on a constant inclusive discourse. Based in African-American traditions of call-and-response, hip-hop is always looking for voices to speak to each other and push the conversation further. In my thesis, I open up an exploration of the role of an author in hip-hop. Paying specific attention to the rapper, I flesh out the ways western ideas of reading conflate and disrupt the structures of a cipher in hip-hop. Imposing an “author-function” on rappers, displaces the call-and-response relationship that hip-hop thrives on. While hip-hop becomes more prevalent in popular culture, rappers have to learn to navigate within and outside of the immediate hip-hop community. As a case study, I examine the career trajectory of Jay Z. Sean Carter employs the site of enunciation that Jay Z creates to transcend and transform his experiences into a platform for creative expressions as well as lucrative business ventures. Finally, this thesis serves as an initial inquiry into future research plans to explore rappers as nepantler@s and listeners as “digital griots.” Both of these designations represents important rhetorical spaces that allow hip-hop culture to continue to work within a cipher and promote inclusivity. These future plans build towards creating a possible model for more productive collaboration, education, and activism.

This report adresses why the currently used scrambling standard CSA needs a replacement. Proposed replacements to CSA are analyzed to some extent, and an alternative replacement (AES128) is analyzed. One alternative being the CSA3, and the other being the CISSA algorithm. Both of the proposed algorithms use the AES algorithm as a base. The CSA3 combines AES128 with a secret cipher, the XRC, while CISSA uses the AES cipher in a feedback mode. The different utilizations makes CSA3 hardware friendly and CISSA software friendly. The implementation of the Advanced Encryption Standard (AES) is analyzed for a 128 bit key length based design, and a specific implementation is presented.

Stream ciphers are counted as an important part of symmetric encryption method. Their basic idea comes from One-Time-Pad cipher using XOR operator on the plain text and the key to generate the cipher. The present work brings a new idea in symmetric encryption method, which inherits stream key generation idea from synchronous stream cipher and uses division instead of xoring. The Usage of division to combine the plain text with stream key gives numerous abilities to this method that the most important one is using random factors to produce the ciphers.

Neste documento apresentamos uma cifra multicanal inspirada nas técnicas de telecomunicações de espalhamento espectral (Spread Spectrum), ou como também conhecido, difusão espectral, para prevenir escuta em uma rede de computadores TCP/IP. Mostramos que dividindo um texto-ilegível ciphertext em blocos de tamanho fixo e transmitindo-os aleatoriamente através de diversos canais estabelecidos entre os agentes (transmissor - receptor) é possível aumentar a complexidade da criptanálise por um suposto adversário não autorizado que esteja escutando a comunicação, dessa forma aumentando relativamente a segurança. Mostramos teoricamente que o tempo de quebra da cifra multicanal cresce em ordem fatorial ou exponencial em função do número de canais utilizados na comunicação. Além disso, adaptado a um esquema de difusão binária herdado do AES (Advanced Encryption Standard) é possível incrementar a segurança da cifra multicanal para maior resiliência contra a criptanálise diferencial. / In this work we present a multichannel cipher inspired on telecommunications Spread Spectrum techniques to prevent eavesdropping in a TCP/IP network. We show that splitting any ciphertext into fixed size blocks and sending them randomly through multiple channels established between the agents (transmitter and receiver) it is possible to increase the complexity of cryptanalysis by a supposed not authorized adversary that might be eavesdropping the communication, in this way, relatively increasing the security. We show theoretically that the brake time of multichannel cipher grows in factorial or exponential order, in function of the number of channel used in the communication. Moreover adapted to binary spread scheme inherited from AES (Advanced Encryption Standard) it is possible to increase the cipher security for more resilience against differential cryptanalysis.

The goal of this thesis is to design a hardware realization of circuit which will implement the AES algorithm. A motivation was to make an acceleration against the classic software encryption. The acceleration is achieved by special designed parts of the circuit, which correspond to particular operations of the AES algorithm. First, there was necessary to design the circuit. In the next step there was a need to describe the designed circuit by the VHDL language. Then the circuit was simulated and synthesized. Due to comparing the circuit with software processing a software implementation was created. Both implementations were created for the FITKit platform. The hardware implementation is made by the FPGA technology and the software implementation is realized in a microcontroller. The result of the thesis is almost one thousandfold acceleration against the classic software encryption.