Identity-based cryptosystems and signature schemes
Proceedings of CRYPTO 84 on Advances in cryptology
Identity-Based Encryption from the Weil Pairing
SIAM Journal on Computing
An Identity Based Encryption Scheme Based on Quadratic Residues
Proceedings of the 8th IMA International Conference on Cryptography and Coding
On computable isomorphisms in efficient asymmetric pairing-based systems
Discrete Applied Mathematics
Delegating Capabilities in Predicate Encryption Systems
ICALP '08 Proceedings of the 35th international colloquium on Automata, Languages and Programming, Part II
Discrete Applied Mathematics
Adaptive Security in Broadcast Encryption Systems (with Short Ciphertexts)
EUROCRYPT '09 Proceedings of the 28th Annual International Conference on Advances in Cryptology: the Theory and Applications of Cryptographic Techniques
Dual System Encryption: Realizing Fully Secure IBE and HIBE under Simple Assumptions
CRYPTO '09 Proceedings of the 29th Annual International Cryptology Conference on Advances in Cryptology
New techniques for dual system encryption and fully secure HIBE with short ciphertexts
TCC'10 Proceedings of the 7th international conference on Theory of Cryptography
Evaluating 2-DNF formulas on ciphertexts
TCC'05 Proceedings of the Second international conference on Theory of Cryptography
Efficient identity-based encryption without random oracles
EUROCRYPT'05 Proceedings of the 24th annual international conference on Theory and Applications of Cryptographic Techniques
ICISC'05 Proceedings of the 8th international conference on Information Security and Cryptology
Constant-Size structure-preserving signatures: generic constructions and simple assumptions
ASIACRYPT'12 Proceedings of the 18th international conference on The Theory and Application of Cryptology and Information Security
International Journal of Applied Cryptography
Using SMT solvers to automate design tasks for encryption and signature schemes
Proceedings of the 2013 ACM SIGSAC conference on Computer & communications security
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Waters, in 2009, introduced an important technique, called dual system encryption, to construct identity-based encryption (IBE) and related schemes. The resulting IBE scheme was described in the setting of symmetric pairing. A key feature of the construction is the presence of random tags in the ciphertext and decryption key. Later work by Lewko and Waters removed the tags and proceeding through composite-order pairings led to a more efficient dual system IBE scheme using asymmetric pairings whose security is based on non-standard but static assumptions. In this work, we have systematically simplified Waters 2009 IBE scheme in the setting of asymmetric pairing. The simplifications retain tags used in the original description. This leads to several variants, the first one of which is based on standard assumptions and in comparison to Waters' original scheme reduces ciphertexts and keys by two elements each. Going through several stages of simplifications, we finally obtain a simple scheme whose security can be based on two standard assumptions and a natural and minimal extension of the decision Diffie-Hellman problem for asymmetric pairing groups. The scheme itself is also minimal in the sense that apart from the tags, both encryption and key generation use exactly one randomiser each. This final scheme is more efficient than both the previous dual system IBE scheme in the asymmetric setting due to Lewko and Waters and the more recent dual system IBE scheme due to Lewko. We extend the IBE scheme to hierarchical IBE (HIBE) and broadcast encryption (BE) schemes. Both primitives are secure in their respective full models and have better efficiencies compared to previously known schemes offering the same level and type of security.