How to prove yourself: practical solutions to identification and signature problems
Proceedings on Advances in cryptology---CRYPTO '86
Non-interactive zero-knowledge and its applications
STOC '88 Proceedings of the twentieth annual ACM symposium on Theory of computing
Efficient identification and signatures for smart cards
EUROCRYPT '89 Proceedings of the workshop on the theory and application of cryptographic techniques on Advances in cryptology
Random oracles are practical: a paradigm for designing efficient protocols
CCS '93 Proceedings of the 1st ACM conference on Computer and communications security
Non-Interactive and Information-Theoretic Secure Verifiable Secret Sharing
CRYPTO '91 Proceedings of the 11th Annual International Cryptology Conference on Advances in Cryptology
Secure Integration of Asymmetric and Symmetric Encryption Schemes
CRYPTO '99 Proceedings of the 19th Annual International Cryptology Conference on Advances in Cryptology
Group signatures with verifier-local revocation
Proceedings of the 11th ACM conference on Computer and communications security
On the Portability of Generalized Schnorr Proofs
EUROCRYPT '09 Proceedings of the 28th Annual International Conference on Advances in Cryptology: the Theory and Applications of Cryptographic Techniques
Enforcing access control in Web-based social networks
ACM Transactions on Information and System Security (TISSEC)
EUROCRYPT'91 Proceedings of the 10th annual international conference on Theory and application of cryptographic techniques
EUROCRYPT'03 Proceedings of the 22nd international conference on Theory and applications of cryptographic techniques
Get shorty via group signatures without encryption
SCN'10 Proceedings of the 7th international conference on Security and cryptography for networks
Relationship-based access control: protection model and policy language
Proceedings of the first ACM conference on Data and application security and privacy
Foundations of group signatures: the case of dynamic groups
CT-RSA'05 Proceedings of the 2005 international conference on Topics in Cryptology
A public key cryptosystem and a signature scheme based on discrete logarithms
IEEE Transactions on Information Theory
Multiparty Access Control for Online Social Networks: Model and Mechanisms
IEEE Transactions on Knowledge and Data Engineering
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Many Internet users today use an electronic social network service (SNS) to share data with their friends. Most SNSs let users restrict access to their shared data, e.g., to particular groups of friends, or to users satisfying other criteria based on their attributes or relationships. Usually, however, such access control restrictions can only be applied to resources hosted on the SNS itself. In this paper, we present protocols to enable SNS users to protect access to resources that are hosted on external service providers (SPs). Our mechanisms preserve the users' privacy in the sense that (1) the SP does not learn the SNS-identities of users that share or access the resource, nor does it learn anything about the access policy that protects it, (2) the SNS does not obtain any information about the resource, and in particular, does not obtain a link to it, and (3) the SP cannot change the policy set by the owner of the resource, or test the policy on users who never requested access to the resource. We give formal definitions of these security requirements and present a cryptographic protocol based on group signatures that provably fulfills them. We also discuss to what extent our requirements can be fulfilled using the standard OAuth authorization protocol while making only minor changes to the SNS infrastructure.