论文标题

基于公共密钥身份验证中多个身份验证者的所有权的密钥管理

Key Management Based on Ownership of Multiple Authenticators in Public Key Authentication

论文作者

Hatakeyama, Koudai, Kotani, Daisuke, Okabe, Yasuo

论文摘要

公共密钥身份验证(PKA)已在各种服务中部署,以向用户提供更强的身份验证。在PKA中,用户在其设备上管理着名为Authenticators的私钥,服务将相应的公共钥匙绑定到其帐户。为了保护私钥,用户使用了从未在外面导出私钥的身份验证器。另一方面,用户定期使用多个身份验证器,例如PC和智能手机。她根据他们的生命周期取代了一些身份验证者,例如购买新设备和丢失的设备。每当她用服务注册新帐户并取代她的一些身份验证者时,用户在许多服务中注册,更新和撤销公共钥匙是一个负担。为了减轻负担,我们提出了一种机制,用户和服务根据身份验证者的所有者和用户可以使用其任何身份验证者访问PKA服务。我们引入了一个称为所有权验证密钥(OVK)的密钥对,该密钥由私钥(OVSK)和相应的公共密钥(OVPK)组成。用户拥有的所有身份验证者都从称为种子的预共享秘密中得出相同的OVSK。服务使用相应的OVPK验证身份验证者的所有权,以确定是否将所请求的公钥绑定到其帐户中。为了保护用户隐私的同时保持便利性,身份验证者独立为种子生成了不同的OVK。我们通过实施概念证明证明了可行性,表明我们提出的机制实现了一些安全目标,并讨论了该机制如何减轻威胁未完全处理。

Public key authentication (PKA) has been deployed in various services to provide stronger authentication to users. In PKA, a user manages private keys on her devices called authenticators, and services bind the corresponding public keys to her account. To protect private keys, a user uses authenticators which never export private keys outside. On the other hand, a user regularly uses multiple authenticators like PCs and smartphones. She replaces some of her authenticators according to their lifecycle, such as purchasing new devices and losing devices. It is a burden for a user to register, update and revoke public keys in many services every time she registers new accounts with services and replaces some of her authenticators. To ease the burden, we propose a mechanism where users and services manage public keys based on the owner of authenticators and users can access services with PKA using any of their authenticators. We introduce a key pair called an Ownership Verification Key (OVK), which consists of the private key (OVSK) and the corresponding public key (OVPK). All authenticators owned by a user derive the same OVSK from the pre-shared secret called the seed. Services verify the ownership of the authenticators using the corresponding OVPK to determine whether binding the requested public key to her account. To protect user privacy while maintaining convenience, authenticators generate a different OVK for each service from the seed independently. We demonstrate the feasibility through the Proof of Concept implementation, show that our proposed mechanism achieves some security goals, and discuss how the mechanism mitigates threats not completely handled.

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