HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Conference papers

Tightly Secure IBE under Constant-size Master Public Key

Abstract : Chen and Wee [CRYPTO, 2013] proposed the first almost tightly and adaptively secure IBE in the standard model and left two open problems which called for a tightly secure IBE with (1) constant-size master public key and/or (2) constant security loss. In this paper, we propose an IBE scheme with constant-size master public key and tighter security reduction. This (partially) solves Chen and Wee's first open problem and makes progress on the second one. Technically, our IBE scheme is built based on Wee's petit IBE scheme [TCC, 2016] in the composite-order bilinear group whose order is product of four primes. The sizes of master public key, ciphertexts, and secret keys are not only constant but also nearly optimal as Wee's petit IBE. We can prove its adaptive security in the multi-instance, multi-ciphertext setting [PKC, 2015] based on the decisional subgroup assumption and a subgroup variant of DBDH assumption. The security loss is O(log q) where q is the upper bound of the total number of secret keys and challenge ciphertexts revealed to adversary in each single IBE instance. It's much smaller than those for all known adaptively secure IBE schemes in a concrete sense.
Document type :
Conference papers
Complete list of metadata

Cited literature [30 references]  Display  Hide  Download

Contributor : Benoit Libert Connect in order to contact the contributor
Submitted on : Tuesday, November 21, 2017 - 2:19:13 PM
Last modification on : Monday, May 16, 2022 - 4:58:02 PM


Files produced by the author(s)


  • HAL Id : hal-01643457, version 1



Jie Chen, Junqing Gong, Jian Weng. Tightly Secure IBE under Constant-size Master Public Key. PKC 2017 - Public Key Cryptography, Mar 2017, Amsterdam, Netherlands. ⟨hal-01643457⟩



Record views


Files downloads