4 results sorted by ID
Possible spell-corrected query: gcm
Revisiting the Security of COMET Authenticated Encryption Scheme
Shay Gueron, Ashwin Jha, Mridul Nandi
Secret-key cryptography
COMETv1, by Gueron, Jha and Nandi, is a mode of operation for nonce-based authenticated encryption with associated data functionality. It was one of the second round candidates in the ongoing NIST Lightweight Cryptography Standardization Process. In this paper, we study a generalized version of COMETv1, that we call gCOMET, from provable security perspective. First, we present a comprehensive and complete security proof for gCOMET in the ideal cipher model. Second, we view COMET, the...
Non-Uniform Bounds in the Random-Permutation, Ideal-Cipher, and Generic-Group Models
Sandro Coretti, Yevgeniy Dodis, Siyao Guo
Foundations
The random-permutation model (RPM) and the ideal-cipher model (ICM) are
idealized models that offer a simple and intuitive way to assess the
conjectured standard-model security of many important symmetric-key and
hash-function constructions. Similarly, the generic-group model (GGM)
captures generic algorithms against assumptions in cyclic groups by modeling
encodings of group elements as random injections and allows to derive simple
bounds on the advantage of such...
Salvaging Weak Security Bounds for Blockcipher-Based Constructions
Thomas Shrimpton, R. Seth Terashima
The concrete security bounds for some blockcipher-based constructions sometimes become worrisome or even vacuous; for example, when a light-weight blockcipher is used, when large amounts of data are processed, or when a large number of connections need to be kept secure. Rotating keys helps, but introduces a ``hybrid factor'' $m$ equal to the number of keys used. In such instances, analysis in the ideal-cipher model (ICM) can give a sharper picture of security, but this heuristic is called...
Security of Practical Cryptosystems Using Merkle-Damgard Hash Function in the Ideal Cipher Model
Yusuke Naito, Kazuki Yoneyama, Lei Wang, Kazuo Ohta
Since the Merkle-Damgård (MD) type hash functions are differentiable from ROs even when compression functions are modeled by ideal primitives,
there is no guarantee as to the security of cryptosystems when ROs are instantiated with structural hash functions.
In this paper, we study the security of the instantiated cryptosystems whereas
the hash functions have the well known structure of Merkle-Damgård construction with Stam's type-II compression function (denoted MD-TypeII) in the Ideal...
COMETv1, by Gueron, Jha and Nandi, is a mode of operation for nonce-based authenticated encryption with associated data functionality. It was one of the second round candidates in the ongoing NIST Lightweight Cryptography Standardization Process. In this paper, we study a generalized version of COMETv1, that we call gCOMET, from provable security perspective. First, we present a comprehensive and complete security proof for gCOMET in the ideal cipher model. Second, we view COMET, the...
The random-permutation model (RPM) and the ideal-cipher model (ICM) are idealized models that offer a simple and intuitive way to assess the conjectured standard-model security of many important symmetric-key and hash-function constructions. Similarly, the generic-group model (GGM) captures generic algorithms against assumptions in cyclic groups by modeling encodings of group elements as random injections and allows to derive simple bounds on the advantage of such...
The concrete security bounds for some blockcipher-based constructions sometimes become worrisome or even vacuous; for example, when a light-weight blockcipher is used, when large amounts of data are processed, or when a large number of connections need to be kept secure. Rotating keys helps, but introduces a ``hybrid factor'' $m$ equal to the number of keys used. In such instances, analysis in the ideal-cipher model (ICM) can give a sharper picture of security, but this heuristic is called...
Since the Merkle-Damgård (MD) type hash functions are differentiable from ROs even when compression functions are modeled by ideal primitives, there is no guarantee as to the security of cryptosystems when ROs are instantiated with structural hash functions. In this paper, we study the security of the instantiated cryptosystems whereas the hash functions have the well known structure of Merkle-Damgård construction with Stam's type-II compression function (denoted MD-TypeII) in the Ideal...