Survey on Encryption Techniques in Delay and Disruption Tolerant Network

Delay and disruption tolerant network (DTN) is used for long area communication in computer network, where there is no direct connection between the sender and receiver and there was no internet facility. Delay tolerant network generally perform store and forward techniques as a result intermediate node can view the message, the possible solution is using encryption techniques to protect the message. Starting stages of DTN RSA, DES, 3DES encryption algorithms are used but now a day\u27s attribute based encryption (ABE) techniques are used. Attribute based encryption technique can be classified in to two, key policy attribute based encryption (KPABE) and cipher policy attribute based encryption (CPABE). In this paper we perform a categorized survey on different encryption techniques presents in delay tolerant networks. This categorized survey is very helpful for researchers to propose modified encryption techniques. Finally the paper compares the performance and effectiveness of different encryption algorithms

Safe Cryptography Algorithms

V této práci jsou popsány současné kryptografické algoritmy, porovnání jejich vlastností, silné a slabé stránky a vhodné případy použití jednotlivých algoritmů. Hlavními tématy jsou bezpečnost algoritmů, jejich chyby, vylepšení a odolnost proti průnikům. Jako doplněk k šifrám je věnována pozornost i hašovacím funkcím. Také jsou ukázány nejběžnější metody kryptoanalýzy. Jako použití popsaných algoritmů v praxi uvádím systémy pro zabezpečený přenost dat, kterými jsou SSH a SSL/TLS a je proveden také praktický útok na SSL spojení. V závěru se nachází shrnutí a doporučení vybraných bezpečných algoritmů pro další použití a bezpečné parametry spojení pro SSH a SSL/TLS.In this thesis there is description of cryptographic algorithms. Their properties are being compared, weak and strong points and right usage of particular algorithms. The main topics are safeness of algorithms, their bugs and improvements and difficulty of breaching. As a complement to ciphers there are also hash functions taken in consideration. There are also showed the most common methods of cryptanalysis. As a practical application of described algorithms I analyze systems for secure data transfer SSH and SSL/TLS and demonstrate an attack on SSL connection. In conclusion there is recommendation of safe algorithms for further usage and safe parameters of SSH and SSL/TLS connections.