Identity-Based Encryption from the Diffie-Hellman Assumption

Author(s):  
Nico Döttling ◽  
Sanjam Garg
2014 ◽  
Vol 543-547 ◽  
pp. 3156-3159
Author(s):  
Qing Hai Bai ◽  
Ying Zheng ◽  
Qing Hu Wang ◽  
Guo Li Wei ◽  
Hai Chun Zhao ◽  
...  

Grid system has secure requirements of confidential communication, data integrity and non-repudiation. According to the secure requirements for Grid service, the paper proposed an identity-based encryption scheme for Grid, which can solve a series of problem: the privacy of data transmission, validation of integrity of data, key update after long run time and non-repudiation. The scheme is constructed by bilinear paring on elliptic cures and its security can be reduced to the computational Bilinear Diffie-Hellman assumption. Finally, the authors analyses the security and efficiency of this scheme.


2021 ◽  
Vol 68 (3) ◽  
pp. 1-46
Author(s):  
Nico Döttling ◽  
Sanjam Garg

We provide the first constructions of identity-based encryption and hierarchical identity-based encryption based on the hardness of the (Computational) Diffie-Hellman Problem (without use of groups with pairings) or Factoring. Our construction achieves the standard notion of identity-based encryption as considered by Boneh and Franklin [CRYPTO 2001]. We bypass known impossibility results using garbled circuits that make a non-black-box use of the underlying cryptographic primitives.


2017 ◽  
Vol 5 (4RACSIT) ◽  
pp. 38-40
Author(s):  
Andal S. ◽  
Tahera Tasneem ◽  
Meghana Mary ◽  
Ranjitha G. C. ◽  
Deepak N.A.

Identity-based encryption(IBE) is a public key cryptosystem(encoding and decoding) and eliminates the demands of public key infrastructure(PKI) and certificate administration in conventional public key settings. Due to the absence of PKI, the revocation problem is a critical issue in IBE settings. Several revocable IBE schemes have been proposed regarding this issue. Quite recently, by embedding an outsourcing computation technique into IBE, a revocable IBE scheme with a key-update cloud service provider (KU-CSP) was proposed.However, their scheme has two shortcomings. One is that the computation and communication costs are higher than previous revocable IBE schemes. The other shortcoming is lack of scalability in the sense that the KU-CSP must keep a secret value for each user. In the article, we propose a new revocable IBE scheme with a cloud revocation authority (CRA) to solve the two shortcomings namely, the performance is significantly improved and the CRA holds only a system secret for all the users. For security analysis, we demonstrate that the proposed scheme is semantically secure under the decisional bilinear Diffie-Hellman (DBDH) assumption. Finally,we extend the proposed revocable IBE scheme to present a CRA-aided authentication scheme with period-limited privileges for managing a large number of various cloud services.


Cryptography ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 33 ◽  
Author(s):  
Ziyuan Hu ◽  
Shengli Liu ◽  
Kefei Chen ◽  
Joseph Liu

An Identity-based encryption (IBE) simplifies key management by taking users’ identities as public keys. However, how to dynamically revoke users in an IBE scheme is not a trivial problem. To solve this problem, IBE scheme with revocation (namely revocable IBE scheme) has been proposed. Apart from those lattice-based IBE, most of the existing schemes are based on decisional assumptions over pairing-groups. In this paper, we propose a revocable IBE scheme based on a weaker assumption, namely Computational Diffie-Hellman (CDH) assumption over non-pairing groups. Our revocable IBE scheme is inspired by the IBE scheme proposed by Döttling and Garg in Crypto2017. Like Döttling and Garg’s IBE scheme, the key authority maintains a complete binary tree where every user is assigned to a leaf node. To adapt such an IBE scheme to a revocable IBE, we update the nodes along the paths of the revoked users in each time slot. Upon this updating, all revoked users are forced to be equipped with new encryption keys but without decryption keys, thus they are unable to perform decryption any more. We prove that our revocable IBE is adaptive IND-ID-CPA secure in the standard model. Our scheme serves as the first revocable IBE scheme from the CDH assumption. Moreover, we extend our scheme to support Decryption Key Exposure Resistance (DKER) and also propose a server-aided revocable IBE to decrease the decryption workload of the receiver. In our schemes, the size of updating key in each time slot is only related to the number of newly revoked users in the past time slot.


Identity-based coding/encryption (IBE) is a public key encrypted system that take outs the strain of public key infrastructure (PKI) and certified administration in standard crypto public key settings. In this public key system is not used, the downside may be a crucial thing in IBE settings. Many IBE schemes are proposed relating to this issue. Recently, by embedding associate degree computation techniques has been into IBE, Li et al. proposed an Identity-based encryption theme along with a keyupdate cloud service supplier. Their theme has 2 things one is that the computation overhead and other is communication prices are more than previous IBE schemes. The defect is lack of quantify ability within the sense that the key-update cloud service supplier should keep a secret worth for every user. With this article, we have a tendency to propose a replacement rescindable IBE theme with a cloud revocation authority (CRA) to solve the problems of 2 short things. The work is drastically improved and also the cloud revocation authority holds a secret for all users. For security purpose, we have a tendency to show that the proposed theme is totally secure beneath the additive Diffie-Hellman key Exchange (DBDH) assumption. Finally, we have a tendency to extend the proposed Identity-based encryption theme to gift a CRA cloud revocation authority authentication theme with limited privileges for an oversized range of assorted cloud technique services.


2020 ◽  
Vol 33 (4) ◽  
pp. 1787-1821
Author(s):  
Roman Langrehr ◽  
Jiaxin Pan

Abstract We construct the first tightly secure hierarchical identity-based encryption (HIBE) scheme based on standard assumptions, which solves an open problem from Blazy, Kiltz, and Pan (CRYPTO 2014). At the core of our constructions is a novel randomization technique that enables us to randomize user secret keys for identities with flexible length. The security reductions of previous HIBEs lose at least a factor of Q, which is the number of user secret key queries. Different to that, the security loss of our schemes is only dependent on the security parameter. Our schemes are adaptively secure based on the Matrix Diffie-Hellman assumption, which is a generalization of standard Diffie-Hellman assumptions such as k-Linear. We have two tightly secure constructions, one with constant ciphertext size, and the other with tighter security at the cost of linear ciphertext size. Among other things, our schemes imply the first tightly secure identity-based signature scheme by a variant of the Naor transformation.


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