International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Dalia Khader

Publications

Year
Venue
Title
2008
EPRINT
Authenticating with Attributes
Dalia Khader
Attribute based group signature (ABGS) is a a new generation of group signature schemes. In such a scheme the verifier could define the role of a signer within the group. He determines the attributes possessed by the member signing the document. In this paper we propose the first ABGS scheme with multi-authorities and define its security notions. We construct an ABGS that is proved to be fully traceable and fully anonymous. Our scheme is efficient and secure.
2007
EPRINT
Attribute Based Group Signature Scheme
Dalia Khader
Alice needs a document signed by an employee in Bob's company. That employee should be part of the IT staff and is at least a junior manager in the cryptography team or a senior manager in the biometrics team. In such a scenario we need an Attribute Based Group Signature Scheme (ABGS). In this paper we define the first ABGS scheme where verifying includes authenticating a person that belongs to a certain group and owns particular attributes. We define two security notions adopted from group signature which are: traceability and anonymity. We prove our scheme to be secure under those two notions.
2007
EPRINT
Attribute Based Group Signature with Revocation
Dalia Khader
In real life, one requires signatures to be from people who fulfill certain criteria, implying that they should possess specific attributes. For example, Alice might want a signature from an employee in Bob’s company who is a member in the IT staff, a senior manager within the biometrics team or at least a junior manager in the cryptography team. In such a case an Attribute Based Group Signature scheme (ABGS) could be applied. Group signature schemes are those where each member of a group can sign on behalf of the others. An ABGS scheme is a type of group signature scheme, where the signing member has to have certain attributes. In[12], the authors introduced the first ABGS but it lacked the ability to revoke. In this paper, we introduce a new scheme that will enable us to remove a member from a group or remove some of his attributes, when needed.
2006
EPRINT
Public Key Encryption with Keyword Search based on K-Resilient IBE
Dalia Khader
Abstract. An encrypted email is sent from Bob to Alice. A gateway wants to check whether a certain keyword exists in an email or not for some reason (e.g. routing). Nevertheless Alice does not want the email to be decrypted by anyone except her including the gateway itself. This is a scenario where public key encryption with keyword search (PEKS) is needed. In this paper we construct a new scheme (KR-PEKS) the KResilient Public Key Encryption with Keyword Search. The new scheme is secure under a chosen keyword attack without the random oracle. The ability of constructing a Public Key Encryption with Keyword Search from an Identity Based Encryption was used in the construction of the KR-PEKS. The security of the new scheme was proved by showing that the used IBE has a notion of key privacy. The scheme was then modified in two different ways in order to fulfill each of the following: the first modification was done to enable multiple keyword search and the other was done to remove the need of secure channels.