We provide a stronger definition of anonymity in the context of shared symmetric key primitives, and show that existing schemes do not provide this level of anonymity. A new scheme is presented to share symmetric key operations amongst a set of participants according to a (t, n)-threshold access structure. We quantify the amount of information the output of the shared operation provides about t...

On the basis of the bachelor thesis ”performance comparison of cryptographic algorithms in Smart Grid applications” supervised by Dipl. Inf. Michael Niedermeier and Prof. Dr. Hermann de Meer at the chair of Computer Networks and Communications, this paper covers the analysis of the privacy ensuring capabilities of homomorphic cryptography in the Smart Grid with regard to its energy efficiency. ...

Classification of vectorial Boolean functions up to affine equivalence is used widely to analyze various cryptographic and implementation properties of symmetric-key algorithms. We show that there exist 75 affine equivalence classes of 5-bit quadratic permutations. Furthermore, we explore important cryptographic properties of these classes, such as linear and differential properties and degrees...

Wireless Sensor Network (WSN) consists of huge number of sensor nodes which are small and inexpensive with very limited resources. The public key cryptography is undesirable to be used in WSN because of the limitations of the resources. A key management and predistribution techniques are required to apply the symmetric key cryptography in such a big network. Many key predistribution techniques ...

Current e-mail security systems base their security on the secrecy of the long-term private key. If this private key is ever compromised, an attacker can decrypt any messages— past, present, or future—encrypted with the corresponding public key. The system described in this paper uses short term private-key/public-key key pairs to reduce the magnitude of this vulnerability.

This paper proposes more various key generation algorithms than conventional encryption method, and more secure encryption method that does not keep each symmetric key of key generation algorithm in server. After implementing proposed system, we verify the system using various sizes of video data. We get the fact that proposed system can reduce the delay time of encryption and decryption at the...

We show how to transform any additively homomorphic privatekey encryption scheme that is compact, into a public-key encryption scheme. By compact we mean that the length of a homomorphically generated encryption is independent of the number of ciphertexts from which it was created. We do not require anything else on the distribution of homomorphically generated encryptions (in particular, we do...

There are many applications of symmetric cryptography where the only realistic option is to predistribute key material in advance of deployment, rather than provide online key distribution. The problem of how most effectively to predistribute keys is inherently combinatorial. We revisit some early combinatorial key predistribution shemes and discuss their limitations. We then explain why this p...

In this paper, a novel asymmetric public-key watermarking scheme is proposed. The watermark is embedded with the use of a private key, while the decoding uses only simple public key. The asymmetric watermark carries certain number of bits of information. However, neither the knowledge of a public key, nor the knowledge of the hidden information, does not allow the attacker to remove the waterma...

Recently J. and R.M. Campello de Souza proposed a private-key encryption scheme based on the product codes with the capability of correcting a special type of structured errors. In this paper, we show that J. and R.M. Campello de Souza’s scheme is insecure against chosen-plaintext attacks, and consequently propose a secure modified scheme.