Maged Hamada Ibrahim

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Incoercible (or deniable) encryption is an important notion that allows a user (a sender and/or a receiver) to escape a coercion attempted by a coercive adversary. Such an adversary approaches the coerced user after transmission forcing him to reveal all his random inputs used during encryption or decryption. Since traditional encryption schemes commits the(More)
The nature of the RSA public modulus N as a composite of at least two secret large primes was always considered as a major obstacle facing the RSA function sharing without the help of a trusted dealer. The incorporated parties must agree on a suitable RSA modulus with no information revealed to them about its prime factors. Enormous number of trials must be(More)
Alice holds a secret integer a while Bob holds a secret integer b, they want to decide on the predicate a &gt; b with no information revealed other than the result. This is the well known Yao's millionaires' problem. In some e-commerce applications, Alice holds an n-dimension secret vector alpha = (a<sub>1</sub>, ..., a<sub>n</sub>) while Bob holds an(More)
In [15] an efficient two-party, two-prime RSA function sharing protocol was proposed. The protocol proves efficiency over previously proposed protocols. When the sharing of standard RSA is considered, the protocol is faster than ever. In this paper, under the assumption that the adversary has eavesdropping and halting capabilities, we propose an efficient(More)
BACKGROUND AND OBJECTIVES Mutual authentication is a very important service that must be established between sensor nodes in wireless body area network (WBAN) to ensure the originality and integrity of the patient's data sent by sensors distributed on different parts of the body. However, mutual authentication service is not enough. An adversary can benefit(More)
Deniable encryption is an important notion that allows a user (a sender and/or a receiver) to escape a coercion attempted by a coercive adversary. Such an adversary approaches the coerced user after transmission forcing him to reveal all his random inputs used during encryption or decryption. Since traditional encryption schemes commits the user to his(More)
Linkable democratic group signatures (LDGS) [29] allow every member of a group to trace the identity of any other member who issued a signature while non-members (with the help of unique pseudonyms) are only able to link the signatures issued by the same signer without being able to trace the signer’s identity. LDGS avoid centralized management authorities(More)
Bitcoin is the first decentralized peer-to-peer electronic virtual asset and payment cryptocurrency, through which, users can transact digital currency directly, without the need for an intermediary (or authority), using a hashed version of cryptographic public keys, as pseudonyms called addresses. The Bitcoin ecosystem was supposed to be anonymous and(More)
Verifiable secret sharing schemes (VSS) are schemes for the purpose of ensuring that the players are sharing a unique secret and this secret is the secret originally distributed by the dealer if the dealer was honest. However, such schemes do not ensure that the shared secret has any special characteristics (such as being a prime, safe prime or being with a(More)
Recently, private enterprises, governmental and military institutions have been relied mainly on digitizing their work. Digital files containing sensitive information should be protected against external and internal malicious attacks. Enterprise digital rights management (E-DRM) schemes provides several approaches to protect and securely distribute digital(More)