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The process of disguising a plaintext into ciphertext is called encryption and back into plaintext is called decryption. A cryptographic algorithm, is also called a cipher, is the mathematical function used for encryption and decryption. Many algorithms are available for this purpose. Triple DES is such an algorithm. Encryption using triple DES is possible in two different ways; they are triple DES with two keys and triple DES with three different keys. Cryptanalysis can be used to recover the plaintext of a message from the ciphertext without access to or knowing the key. Exhaustive key search remains the most practical and efficient attack on Triple DES with two keys. The principles of quantum mechanics can be used to build and analyze a quantum computer and its algorithms. Quantum searching is one such algorithm. The key search in Triple DES with two keys is possible using quantum search algorithm, which is more efficient compare to any other methods. In this paper we are presenting how quantum search can be used to crack Triple DES with two keys searching for a key. [ABSTRACT FROM AUTHOR]

In number of Internet applications we need to search for objects to down load them. This includes peer-to-peer (P2P) file sharing, grid computing and content distribution networks. Here the single object will be searched for in multiple servers. There are many searching algorithms existing today for this purpose and uses the concept of classical physics and classical algorithms. The principles of quantum mechanics can be used to build and analyze a quantum computer and its algorithms. Quantum searching is one such algorithm. In this paper we are proposing a search method based on quantum physics and quantum algorithms. [ABSTRACT FROM AUTHOR]

Quantum computing is an important field of research that applies concepts of quantum physics to building more efficient computers. Although only rudimentary quantum computers have been built so far, many researchers believe that quantum computing has great potential and the quantum computers can efficiently perform some tasks which are otherwise not feasible on a classical computer, The Hamiltonian cycle problem is to determine whether a given graph has a Hamiltonian cycle or not. This problem belongs to the class of NP-complete problems, widely believed to intractable or hard on classical computers. Design of faster-than-classical quantum algorithms for important algorithmic problems has been an interesting intellectual adventure and achievement all along and their existence keeps being one of the key stimuli to those trying to overcome enormous technology problems to build (powerful) quantum computers. In this paper, we have used undirected graphs with varied number of vertices and we have shown how to determine the existence of a Hamiltonian cycle in a given graph. We have also illustrated how quantum search can be applied to obtain the solution of the Hamiltonian cycle problem much faster than the classical approach. [ABSTRACT FROM AUTHOR]