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\begin{document}
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\title{A Hierarchical Key Assignment Scheme}



\author[1]{Baris Celiktas }%
\author[2]{Ibrahim Çelikbilek}%
\author[2]{Sueda Guzey }%
\author[2]{Enver Ozdemır }%
\affil[1]{Isik University}%
\affil[2]{Affiliation not available}%


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  \date{May 06, 2026}


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\begin{abstract}
This work proposes a new access control scheme that utilizes a
hierarchical key assignment mechanism based on inner product spaces. The
scheme brings a lightweight computational load to each entity and is
designed to be applicable in a digital medium that implements
hierarchical access control policies. By utilizing the method of
orthogonal projection and distributing a basis to each group, the scheme
enables flexible and efficient left-to-right and top-down policy for any
dynamic update or change in the hierarchical structure.~ The scheme
allows a parent group to obtain the secret keys of its child groups, but
not the other way around. It is resistant to collusion attacks and
privilege creep problems and provides key recovery and
indistinguishability property. The scheme has a low storage overhead,
and utilizes an efficient key derivation process.%
\end{abstract}%



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