Securing a wireless communication has generally a vital importance, particularly when this communication is in a hostile environment like in wireless sensor networks (WSNs). The problem is how to create cryptographic keys between sensor nodes to ensure secure communications. Limited resources of sensor nodes make a public key cryptosystem such as RSA not feasible. So, most solutions rely on a s...

Steganography and cryptography are used to send the data in a confidential way. Steganography hides the existing message and cryptography will confuse the message. The transformation of plain text to cipher text is called as encryption. The transformation of cipher text to plain text is called decryption. Encryption and decryption are controlled by keys. Hashing, symmetric and asymmetric algori...

In these lecture notes we survey the state of the art in symmetric key encryption, in particular in the block ciphers and stream ciphers area. The areas of symmetric key encryption has been very active in the last five years due to growing interest from academic and industry research, standardization efforts like AES, NESSIE and CRYPTREC, as well as due to ease of government control over export...

Tool-supported proofs of security protocols typically rely on abstractions from real cryptography by term algebras, so-called Dolev-Yao models. However, until recently it was not known whether a Dolev-Yao model can be implemented with real cryptography in a provably secure way under active attacks. For public-key encryption and signatures, this was recently shown, if one accepts a few additions...

Many key management schemes have been proposed in systematically deployed Wireless Sensor Networks (WSNs).The sensor nodes are equipped with inadequate battery power, low memory, limited computation and communication range. Energy efficient secure routing is major issue in wireless sensor networks. In this paper, the hybrid key management scheme is proposed by combining public key cryptography ...

Recently, chaos has attracted much attention in the field of cryptography. To study the security with a known image of a symmetric image encryption scheme, the attack algorithm of equivalent key is given. We give the known image attacks under different other conditions to obtain the equivalent key. The concrete step and complexity of the attack algorithm is given. So the symmetric image encrypt...

Motivated by cryptography, permutations induced by polynomial functions on finite lattices L = (L,∨,∧,∗ ) with an antitone involution ∗ are investigated. These permutations together with the operation of composition form a subgroup of the symmetric group on L. We describe the structure of this subgroup for different classes of lattices L and indicate possible applications by outlining a protoco...

Information security is one of the major concerns while transferring some information publicly. With the advancement in the communication medium there are chances of more threats in the communication system. In this work, we have focused on the threats associated with SMS (Short Message Service) Communication in android environment. The work is about to define an effective symmetric cryptograph...

Random sequences play an important role in all aspects of Cryptography. All cryptographic systems and protocols are based on secrets and can only be as strong as the random sequence generators they use to generate those secrets. The best cryptographic scheme becomes insecure once its secrets can be predicted or determined. In modern cryptography random sequences are used (1) to generate session...