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Shared-Custodial Password-Authenticated Deterministic Wallets

Das, Poulami ; Erwig, Andreas ; Faust, Sebastian (2024)
Shared-Custodial Password-Authenticated Deterministic Wallets.
14th International Conference on Security and Cryptography for Networks (SCN 2024). Amalfi, Italy (11.09.2024 - 13.09.2024)
doi: 10.1007/978-3-031-71073-5_16
Konferenzveröffentlichung, Bibliographie

Kurzbeschreibung (Abstract)

Cryptographic wallets are an essential tool in Blockchain networks to ensure the secure storage and maintenance of an user's cryptographic keys. Broadly, wallets can be divided into three categories, namely custodial, non-custodial, and shared-custodial wallets. The first two are centralized solutions, i.e., the wallet is operated by a single entity, which inherently introduces a single point of failure. Shared-custodial wallets, on the other hand, are maintained by two independent parties, e.g., the wallet user and a service provider, and hence avoid the single point of failure centralized solutions. Unfortunately, current shared-custodial wallets suffer from significant privacy issues.

In our work, we introduce password-authenticated deterministic wallets (PADW), a novel and efficient shared-custodial wallet solution, which exhibits strong security and privacy guarantees. In a nutshell, in a PADW scheme, the secret key of the user is shared between the user and the server. In order to generate a signature, the user first authenticates itself to the server by providing a password and afterwards engages in an interactive signing protocol with the server. Security is guaranteed as long as at most one of the two parties is corrupted. Privacy, on the other hand, guarantees that a corrupted server cannot link a transaction to a particular user. We formally model the notion of PADW schemes and we give an instantiation from blind Schnorr signatures. Our construction allows for deterministic key derivation, a feature that is widely used in practice by existing wallet schemes, and it does not rely on any heavy cryptographic primitives. We prove our scheme secure against adaptive adversaries in the random oracle model and under standard assumptions. That is, our security proof only relies on the assumption that the Schnorr signature scheme is unforgeable and that a public key encryption scheme is CCA-secure.

Typ des Eintrags: Konferenzveröffentlichung
Erschienen: 2024
Autor(en): Das, Poulami ; Erwig, Andreas ; Faust, Sebastian
Art des Eintrags: Bibliographie
Titel: Shared-Custodial Password-Authenticated Deterministic Wallets
Sprache: Englisch
Publikationsjahr: 10 September 2024
Verlag: Springer
Buchtitel: Security and Cryptography for Networks
Reihe: Lecture Notes in Computer Science
Band einer Reihe: 14974
Veranstaltungstitel: 14th International Conference on Security and Cryptography for Networks (SCN 2024)
Veranstaltungsort: Amalfi, Italy
Veranstaltungsdatum: 11.09.2024 - 13.09.2024
DOI: 10.1007/978-3-031-71073-5_16
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Kurzbeschreibung (Abstract):

Cryptographic wallets are an essential tool in Blockchain networks to ensure the secure storage and maintenance of an user's cryptographic keys. Broadly, wallets can be divided into three categories, namely custodial, non-custodial, and shared-custodial wallets. The first two are centralized solutions, i.e., the wallet is operated by a single entity, which inherently introduces a single point of failure. Shared-custodial wallets, on the other hand, are maintained by two independent parties, e.g., the wallet user and a service provider, and hence avoid the single point of failure centralized solutions. Unfortunately, current shared-custodial wallets suffer from significant privacy issues.

In our work, we introduce password-authenticated deterministic wallets (PADW), a novel and efficient shared-custodial wallet solution, which exhibits strong security and privacy guarantees. In a nutshell, in a PADW scheme, the secret key of the user is shared between the user and the server. In order to generate a signature, the user first authenticates itself to the server by providing a password and afterwards engages in an interactive signing protocol with the server. Security is guaranteed as long as at most one of the two parties is corrupted. Privacy, on the other hand, guarantees that a corrupted server cannot link a transaction to a particular user. We formally model the notion of PADW schemes and we give an instantiation from blind Schnorr signatures. Our construction allows for deterministic key derivation, a feature that is widely used in practice by existing wallet schemes, and it does not rely on any heavy cryptographic primitives. We prove our scheme secure against adaptive adversaries in the random oracle model and under standard assumptions. That is, our security proof only relies on the assumption that the Schnorr signature scheme is unforgeable and that a public key encryption scheme is CCA-secure.

Zusätzliche Informationen:

Proceedings, Part II

Fachbereich(e)/-gebiet(e): 20 Fachbereich Informatik
20 Fachbereich Informatik > Angewandte Kryptographie
DFG-Sonderforschungsbereiche (inkl. Transregio)
DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche
DFG-Graduiertenkollegs
DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 1119: CROSSING – Kryptographiebasierte Sicherheitslösungen als Grundlage für Vertrauen in heutigen und zukünftigen IT-Systemen
Hinterlegungsdatum: 29 Okt 2024 12:30
Letzte Änderung: 29 Okt 2024 12:38
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