Chiara Marcolla

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Bilinear groups are often used to create Attribute-Based En-cryption (ABE) algorithms. In particular, they have been used to create an ABE system with multi authorities, but limited to the ciphertext-policy instance. Here, for the first time, we propose a multi-authority key-policy ABE system. In our proposal, the authorities may be set up in any moment and(More)
We investigate the geometry of the support of small weight code-words of dual algebraic geometric codes on smooth complete intersections by applying the powerful tools recently developed by Alain Cou-vreur. In particular, by restricting ourselves to the case of Hermitian codes, we recover and extend previous results obtained by the second named author joint(More)
We study the locally recoverable codes on algebraic curves. In the first part of this article, we provide a bound of generalized Hamming weight of these codes. Whereas in the second part, we propose a new family of algebraic geometric LRC codes, that are LRC codes from Norm-Trace curve. Finally, using some properties of Hermitian codes, we improve the(More)
We classify completely the intersections of the Hermitian curve with parabolas in the affine plane. To obtain our results we employ well-known algebraic methods for finite fields and geometric properties of the curve automorphisms. In particular, we provide explicit counting formulas that have also applications to some Hermitian codes.
Bilinear groups are often used to create Attribute-Based Encryption (ABE) algorithms. In our proposal, a Multiple-Authorities Key-Policy Attribute-Based Encryp-tion scheme is constructed in which the authorities collaborate to achieve shorter keys and parameters, enhancing the efficiency of encryption and decryption. We prove our system secure under an(More)
For any affine-variety code we show how to construct an ideal whose solutions correspond to codewords with any assigned weight. We are able to obtain geometric characterizations for small-weight codewords for some families of Hermitian codes over any F q 2. From these geometric characterizations, we obtain explicit formulas. In particular, we determine the(More)
The correctness in decrypting a ciphertext after some operations in the DGVH scheme depends heavily on the dimension of the secret key. In this paper we compute two bounds on the size of the secret key for the DGHV scheme to decrypt correctly a ciphertext after a fixed number of additions and a fixed number of multiplication. Moreover we improve the(More)
The correctness in decrypting a ciphertext after some operations in the DGVH scheme depends heavily on the dimension of the secret key. In this paper we compute two bounds on the size of the secret key for the DGHV scheme to decrypt correctly a ciphertext after a fixed number of additions and a fixed number of multiplication. Moreover we improve the(More)
Bilinear groups are often used to create Attribute-Based Encryption (ABE) algorithms. In particular, they have been used to create an ABE system with multi authorities, but limited to the ciphertext-policy instance. Here, for the first time, we propose two multi-authority key-policy ABE systems. In our first proposal, the authorities may be set up in any(More)
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