Sökning: "Ciphers"

Visar resultat 1 - 5 av 14 avhandlingar innehållade ordet Ciphers.

1. 1. On Boolean Functions in Symmetric-Key Ciphers

   Författare :Enes Pasalic; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; autocorrelation properties; correlation attacks; nonlinearity; resiliency; Boolean function; Stream ciphers; block ciphers; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : This thesis discusses new results on the design and the existence of cryptographically strong Boolean functions used in the design of stream and block ciphers. By interlinking theoretical results and computer search some open problems have been solved, that is, we have shown the existence of previously unknown classes of functions. LÄS MER

3. 2. Distributed stream ciphers

   Författare :Magnus Öberg; Ben Smeets; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Cryptographic operations are normally carried out by a single machine. Sometimes, however, this machine cannot be trusted completely. Threshold cryptography offers an alternative where the cryptographic operation is distributed to a group of machines in such a way that the key used in the cryptographic operation is not revealed to anyone. LÄS MER

4. 3. Some Results on Distinguishing Attacks on Stream Ciphers

   Författare :Håkan Englund; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; correlation attack; irregularly clocked filter generator; distinguishing attacks; Stream ciphers; filter generator; Pomaranch; Dragon; LILI-128; LILI-II;

   Sammanfattning : Stream ciphers are cryptographic primitives that are used to ensure the privacy of a message that is sent over a digital communication channel. In this thesis we will present new cryptanalytic results for several stream ciphers. LÄS MER

5. 4. On the Design and Analysis of Stream Ciphers

   Författare :Martin Hell; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; weak feedback polynomials; bit-search generator; self-shrinking generator; Achterbahn; Pomaranch; Grain-128; Grain; stream ciphers; cryptography; cryptanalysis; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : This thesis presents new cryptanalysis results for several different stream cipher constructions. In addition, it also presents two new stream ciphers, both based on the same design principle. The first attack is a general attack targeting a nonlinear combiner. LÄS MER

7. 5. Cryptanalysis of Selected Stream Ciphers

   Författare :Paul Stankovski; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stream cipher; cryptanalysis; FCSR; state recovery; linear relations; optimal sampling; distinguisher; HC; nonrandomness; greedy bit set algorithm.;

   Sammanfattning : The aim of this dissertation is to show some cryptanalytical results on a selection of stream ciphers. We have grouped theory and results into three main parts. The first part focuses on the FCSR-based constructions X-FCSR and F-FCSR-H v3. For the X-FCSR family of stream ciphers we perform a severe state recovery attack. LÄS MER