Sökning: "block ciphers"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden block 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. On Some Symmetric Lightweight Cryptographic Designs

   Författare :Martin Ågren; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lightweight cryptography; integrity; authentication; symmetric cryptography; stream ciphers; block ciphers; Grain-128a; BEAN; KTANTAN; textsc{PRINTcipher}; FCSR combiner; related-key attack; linear cryptanalysis; linear correlations; invariant subspace attack.;

   Sammanfattning : This dissertation presents cryptanalysis of several symmetric lightweight primitives, both stream ciphers and block ciphers. Further, some aspects of authentication in combination with a keystream generator is investigated, and a new member of the Grain family of stream ciphers, Grain-128a, with built-in support for authentication is presented. LÄS MER

4. 3. 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

5. 4. On LFSR based Stream Ciphers - analysis and design

   Författare :Patrik Ekdahl; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-shrinking generator; shrinking generator; E0; A5; sober; stream cipher; LFSR; snow; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : Stream ciphers are cryptographic primitives used to ensure privacy in digital communication. In this thesis we focus on stream ciphers built using Linear Feedback Shift Registers (LFSRs). Several different stream ciphers are analysed and new attacks are presented. In addition, two new stream ciphers are presented, both based on the same design. LÄS MER

7. 5. Design and Implementation of Efficient and Secure Lightweight Cryptosystems

   Författare :Shohreh Sharif Mansouri; Elena Dubrova; Vincent Rijmen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : In recent years there has been a wide-spread deployment of battery-powered and passive devices such as RFID tags, systems with very strong limitations on area, cost and power budgets. Deploying cryptographic solutions for these systems is both important, because it could unlock several security-critical applications, and challenging, due to the stringent budgets: the overheads of even the smallest block ciphers are often one or more orders of magnitude too high. LÄS MER