This work presents China RealDID, a three-layer architecture -- CTID (centralized legal identity), RealDID (decentralized anchor on an open permissioned blockchain), and VCs with SD-JWT-based selective disclosure -- evaluated against five adversary classes and six security goals.
Abstract
Verifiable credentials (VCs) and decentralized identifiers (DIDs) enable selective disclosure but lack legal anchoring: without a trusted identity root, verifiers cannot distinguish a genuine holder from a fabricated identity. State identity systems provide biometric-grounded verification but impose three costs: verifiers must collect subjects'full personally identifiable information, infrastructure concentrates on a single API, and the state observes every transaction. We present China RealDID, a three-layer architecture -- CTID (centralized legal identity), RealDID (decentralized anchor on an open permissioned blockchain), and VCs with SD-JWT-based selective disclosure -- evaluated against five adversary classes and six security goals. The central mechanism is a content-blind government relay: the state authenticates participants and counter-signs every credential but cannot read the payload, encrypted by the issuer to the holder's public key. We describe the VC lifecycle, triple-signature chain, open template registry, and the architecture's metadata-level privacy limits, including the credential graph at the relay and presentation linkability from single-DID reuse. The design yields an asymmetric, state-bounded trust model: the state cannot impersonate or read contents; the user cannot fabricate identity or evade metadata observation. We analyze alignment with China's Personal Information Protection Law and the EU's GDPR, including the tension between immutable registries and erasure rights, and discuss generalizability through cross-border deployments with Singapore and Hong Kong.
Cross-silo federated learning must reconcile update authentication, routine identity privacy, and auditable accountability across independently operated institutions. Ordinary digital signatures provide direct attribution but expose the signer of every benign update. Secure aggregation and robust learning address complementary confidentiality and robustness goals, yet they typically do not provide a publicly verifiable interface for post-incident attribution and revocation. We present A3FL, a verifiable accountable anonymous authentication interface for cross-silo federated learning, motivated by regulated institutional collaboration. The interface defines canonical transcripts that bind the payload hash, the complete round context (including the transparency-log digest), registry state, nullifier, auditor-committee key, opening policy, trace ciphertext, and opening evidence. A client proves that an update comes from an authorized, active member without disclosing its identity. An atomic per-round registry-version pin, combined with a round-local nullifier, detects duplicate submissions. A policy-valid incident request and verifiable shares from a threshold quorum of auditors enable publicly verifiable opening and registry-based revocation with respect to the historical state. We instantiate the interface with a Groth16/Edwards backend and implement a prototype that covers registry freshness, duplicate filtering, authorized public opening, revocation, and adversarial transcript validation. Experiments across institutional-scale registry sizes quantify the control-plane costs of anonymous admission, authorized opening, revocation, and the proof backend. A multi-scenario poisoning case study demonstrates how the policy-gated accountability path responds to different incident-evidence conditions.
The rapid growth of digital services has increased the demand for identity systems that provide strong authentication while minimizing unnecessary disclosure of personal information. Conventional identity management architectures generally depend on centralized identity providers and frequently require users to disclose complete identity attributes even when a service requires only a limited assertion. Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs) provide an alternative model in which identity holders can manage cryptographically verifiable credentials independently of a centralized identity provider. However, the privacy guarantees of decentralized identity systems depend substantially on the cryptographic proof mechanism used during credential presentation.
Zero-Knowledge Proofs (ZKPs) enable a prover to demonstrate knowledge of a secret or the validity of a statement without revealing the underlying secret. Different ZKP and selective-disclosure mechanisms exhibit significantly different characteristics with respect to proof size, generation time, verification time, communication overhead, computational requirements, privacy guarantees, interoperability, and implementation complexity. Consequently, selecting a single proof mechanism for every decentralized identity scenario can result in unnecessary computational cost or inadequate privacy protection.
This paper proposes an Adaptive ZKP Selection Framework (AZSF) for privacy-preserving decentralized identity using DIDs and Verifiable Credentials. The framework dynamically selects an appropriate proof mechanism according to the privacy sensitivity of requested attributes, disclosure requirements, verifier trust conditions, computational resources, proof-generation latency, communication constraints, interoperability requirements, and unlinkability requirements. The proposed architecture introduces a policy-driven decision layer between the credential wallet and proof-generation subsystem. It evaluates candidate mechanisms including selective-disclosure signatures, BBS-based proofs, SD-JWT-based selective disclosure, and general-purpose succinct zero-knowledge proof systems such as zk-SNARK/PLONK-style approaches.
A formal multi-criteria decision model is developed to represent the selection process. The framework defines privacy, performance, communication, interoperability, and deployment criteria and computes an adaptive suitability score for each candidate proof mechanism. A threat model covering credential theft, replay, correlation, malicious verifiers, issuer compromise, metadata leakage, and proof substitution is presented. The paper further proposes an experimental methodology for evaluating proof generation time, verification time, proof size, communication overhead, privacy leakage, unlinkability, and resource consumption. The proposed framework provides a systematic foundation for choosing cryptographic proof mechanisms according to application requirements instead of adopting a one-size-fits-all approach.
Index Terms— Decentralized Identity, Decentralized Identifiers, Verifiable Credentials, Zero-Knowledge Proofs, Privacy-Preserving Identity, Selective Disclosure, BBS Signatures, SD-JWT, Self-Sovereign Identity, Privacy Engineering, Adaptive Cryptography.
Sanchita Shukla· International Journal of Cre...· 0 citations
PEACE is presented, an authentication mechanism for blockchains that combines the practicality of traditional Web systems with decentralization and privacy-preservation, building on a recent groundbreaking zkLogin protocol.
Stefan Dziembowski, Shahriar Ebrahimi, Paweł K. ̨edzior et al.· International Conference on...· 0 citations
Verifiable credentials let holders present digitally signed claims without requiring the issuer to participate in every presentation. Revocation complicates this privacy model because a verifier must determine whether a credential remains valid. Existing status checks may expose recurring identifiers, registry positions, or request metadata. Such information can serve as stable handles to link separate presentations. ShadowPath moves the credential status lookup to the holder. For each presentation, the holder proves, in zero-knowledge, that the credential has not been revoked under the verifier-selected registry root. The verifier learns the status result but not observable metadata. To the best of our knowledge, we provide the first evaluation of Verkle trees for credential revocation and compare them with sparse Merkle trees to assess their applicability in real world applications. The comparison tests whether reducing path depth with Verkle trees offsets the higher cost of KZG-based authentication. Across 30 desktop trials, median Groth16 proving took 371.6ms with sparse Merkle and 2.11s with Verkle. Verification took 3.70ms and 7.55ms, respectively. Groth16 Verkle proving took about 3s on both primary mobile devices. The results show that shorter authenticated paths do not necessarily yield cheaper zero-knowledge proofs. With fresh session randomness, verifier-visible status data do not reveal whether two presentations use the same credential under the stated assumption of session-value independence. This guarantee excludes issuer-verifier collusion and synchronization traffic.
Patrick Herbke, Wolf Rieder, Christian René Sechting et al.· 0 citations
Blockchain data is immutable and publicly visible a sensitive signature is placed on-chain, anyone can attempt to verify it. This openness may lead to unintended information exposure. The standard ring signature cannot fully address all the privacy, selective-verification and time -controlled disclosure requirements that arise in modern secure systems. The proposed algorithm presents a Blockchain-based Ring Signature with Multi-Designated Verifier and Zero-Knowledge Proof (BRSMDV-ZKP) enables a signer anonymously authenticate a transaction with a group of public keys while ensuring that only designated verifiers can verify the signature, The scheme incorporates a challenge–response mechanism, randomized commitments, and encrypted verifiers specific data to ensure signer anonymity, trace resistance, and verifier exclusivity. A Zero-Knowledge Proof (ZKP) is employed to prove correct decryption of the signature without revealing the verifier′s private key. The time-lock puzzle enforces a predefined delay, preventing early verification and enabling reward–penalty mechanisms for verifier compliance. This approach reduces the risk of key leakage, preserves privacy in decentralized systems and multi-party environments, and supports secure applications such as confidential e-voting, sealed-bid auctions, and legal document verification on blockchain platforms.
T. S. Vasughi· Journal of Intelligent Decis...· 0 citations
Authentication in Web 3.0 faces a structural conflict. Systems that offer full anonymity leave no lawful way to identify a malicious actor. Systems built for accountability expose a persistent wallet address to blockchain-graph analysis, or fall back on centralized key recovery. Existing designs solve one side of this conflict at the cost of the other. This paper presents PEUAP-W3, a Privacy-Enhanced and User-centric Authentication Protocol. Its contribution is the integration of five established components into a single deployed and formally analyzed system. A Circom 2 circuit of 1579 Groth16 constraints proves four facts in a single 192-byte on-chain proof: knowledge of an opening of the session credential commitment, an SpO2 value inside an 85–100% band, single-use nonce binding, and HMAC integrity. Shamir (k = 2, n = 3) sharing distributes the identity payload across three independent relays. The coordinator reconstructs an identity only after a threshold vote has been recorded on chain. Credentials are issued as W3C Verifiable Credentials 2.0 in did:key form. Four Solidity contracts verify the proof on Ethereum Sepolia. Verification costs about 241,000 gas and takes roughly 3 ms. ProVerif and Scyther find no attack under the Dolev–Yao model. A concurrency sweep to 500 simultaneous requests completes 1191 requests with zero failures at about 15.4 requests per second. A behavioral gate screens commodity abuse as a supplementary control; it is not treated as a security boundary. Against a nine-property framework, PEUAP-W3 satisfies six properties. Three remain conditional and are not verified in the current deployment: biological-origin assurance and digital replay prevention, both of which need an attested sensor; and GDPR erasure equivalence. Here, formally verified refers to the protocol models and theorems, not to the complete deployed software.
Adarsh S. V. Nair, R. Achary· Computers· 0 citations
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