The increasing incidents of data breaches and personal data misuse highlight the urgent need for robust identity management systems. Self-Sovereign Identity (SSI) emerges as the future solution for digital identity management, underpinned by anonymous credentials (AC) and the distributed ledger technology (DLT) for security measures. However, current SSI models only achieve partial decentralization and none of them can fully meet the complex security requirements of real-world applications. In this paper, we address these limitations by constructing a Decentralized Anonymous Credential (DAC) scheme inspired by large universe attribute-based cryptographic primitives. Building on this foundation, we design a distributed identity management system (DisIMS), a comprehensive SSI system built on blockchain, achieving attribute flexibility, anonymity, unlinkability, revocability and selective disclosure. Compared to earlier blockchain-based identity management systems, our DisIMS allows users to selectively link previous transactions to generate verifiable eligibility proofs for the current transaction without leaking their real identities. We also implement DisIMS on both permissioned (Hyperledger Fabric v2.5) and permissionless (Ethereum Sepolia testnet) blockchains. Experimental results show that batch verification outperforms single verification by reducing execution times by approximately 76% to 81% on Hyperledger Fabric and 50% to 71% on Ethereum, based on 200 tests with 10 to 50 credentials containing 50 attributes each, which demonstrates DisIMS practicality for real-world batch verification scenarios.

Abstract A nominative signature (NS) is a non‐self‐authenticating signature that is jointly generated by a signer (or a nominator) and a user (or a nominee), but once generated, its validity can only be determined by the user. No one else including the signer can tell the signature's validity unless the user confirms or disavows so, whereas the user cannot cheat either. One‐move NS is an efficient type of NS that requires the signer to send only one message to the user during the signature generation stage. Currently, there exists only one one‐move NS scheme that is proven secure in the standard model, and is convertible, that is, the user can transform a nominative signature to a publicly verifiable standard signature without the signer's aid. However, the number of elements in the keys of both signer and user grows linearly with the value of the security parameter. In this paper, we propose a new one‐move NS which is convertible, can be proven secure in the standard model, and also has a constant number of elements in the keys of both the signer and the user. We apply the Boneh–Boyen short standard signature in a novel way to build this nominative signature scheme. We show that this new scheme achieves the best performance among all the schemes proven secure in the standard model, and its security relies only on the standard q‐strong Diffie–Hellman and decisional Diffie–Hellman assumptions. Finally, we will present a generic construction by utilizing a secure standard signature scheme and a secure encryption scheme. Copyright © 2013 John Wiley & Sons, Ltd.