Key escrow

About: Key escrow is a research topic. Over the lifetime, 1162 publications have been published within this topic receiving 19616 citations.

An efficient certificateless signature scheme

Abstract: Traditional certificate based cryptosystem requires high maintenance cost for certificate management. Although, identity based cryptosystem reduces the overhead of certificate management, it suffers from the drawback of key escrow. Certificateless cryptosystem combines the advantages of both certificate based and identity based cryptosystems as it avoids the usage of certificates and does not suffer from key escrow. In this paper, we propose a pairing based certificateless signature scheme that is efficient than the existing scheme.

Method for initiating a stream-oriented encrypted communication

Abstract: The invention provides a cryptographic system and method with a key escrow feature that uses a method for verifiably splitting users' private encryption keys into components and for sending those components to trusted agents chosen by the particular users, and provides a system that uses modern public key certificate management, enforced by a chip device that also self-certifies. In a preferred embodiment of this invention, the chip encrypts or decrypts only if certain conditions are met, namely, (1) if a valid “sender certificate” and a valid “recipient certificate” are input, where “valid” means that the particular user's private decryption key is provably escrowed with a specified number of escrow agents and that the master escrow center is registered and certified by the chip manufacturer, and (2) if a valid Message Control Header is generated by the sender and validated by the recipient, thereby giving authorized investigators sufficient information with which to request and obtain the escrowed keys. The methods for key escrow and receiving an escrow certificate are also applied herein to a more generalized case of registering a trusted device with a trusted third party and receiving authorization from that party enabling the device to communicate with other trusted devices. A further preferred embodiment of this invention provides a method for generating verifiably trusted communications among a plurality of users, comprising the steps of escrowing at a trusted escrow center a plurality of asymmetric cryptographic keys to be used by a plurality of users; verifying each of said plurality of keys at the escrow center; certifying the authorization of each of said plurality of keys upon verification; and initiating a communication from each of said plurality of users using a respective one of said plurality of keys contingent upon said certification. This invention also provides for decoding of communications by authorized law enforcement agents, based upon use of the Message Control Header included with each communication, using a special law enforcement decoder box and auditing of the law enforcement wiretaps to prevent abuse by law enforcement and other officials. Further preferred embodiments provide for rekeying and upgrading of device firmware using a certificate system, and encryption of stream-oriented data.

Certificateless Public Integrity Checking of Group Shared Data on Cloud Storage

Abstract: Cloud storage service supplies people with an efficient method to share data within a group. The cloud server is not trustworthy, so lots of remote data possession checking (RDPC) protocols are proposed and thought to be an effective way to ensure the data integrity. However, most of RDPC protocols are based on the mechanism of traditional public key infrastructure (PKI), which has obvious security flaw and bears big burden of certificate management. To avoid this shortcoming, identity-based cryptography (IBC) is often chosen to be the basis of RDPC. Unfortunately, IBC has an inherent drawback of key escrow. To solve these problems, we utilize the technique of certificateless signature to present a new RDPC protocol for checking the integrity of data shared among a group. In our scheme, user's private key includes two parts: a partial key generated by the group manager and a secret value chosen by herself/himself. To ensure the right public keys are chosen during the data integrity checking, the public key of each user is associated with her unique identity, for example the name or telephone number. Thus, the certificate is not needed and the problem of key escrow is eliminated too. Meanwhile, the data integrity can still be audited by public verifier without downloading the whole data. In addition, our scheme also supports efficient user revocation from the group. The security of our scheme is reduced to the assumptions of computational Diffie-Hellman (CDH) and discrete logarithm (DL). Experiment results exhibit that the new protocol is very efficient and feasible.

Removing Escrow from Identity-Based Encryption

Abstract: Key escrow is inherent in identity-based encryption (IBE). A curious key generation center (KGC) can simply generate the user's private key to decrypt a ciphertext. However, can a KGC still decrypt if it does not know the intended recipient of the ciphertext? We answer by formalizing KGC anonymous ciphertext indistinguishability ($\mathcal{ACI-KGC}$). We find that all existing pairing-based IBE schemes without random oracles, whether receipt-anonymous or not, do not achieve KGC one-wayness, a weaker notion of $\mathcal{ACI-KGC}$. In view of this, we first show how to equip an IBE scheme by Gentry with $\mathcal{ACI-KGC}$. Second, we propose a new system architecture with an anonymous private key generation protocol such that the KGC can issue a private key to an authenticated user without knowing the list of users identities. This also better matches the practice that authentication should be done with the local registration authorities instead of the KGC. Our proposal can be viewed as mitigating the key escrow problem in a different dimension than distributed KGCs approach.

Cost-Effective Scalable and Anonymous Certificateless Remote Authentication Protocol

Abstract: Existing anonymous remote authentication protocols to secure wireless body area networks (WBANs) raise challenges such as eliminating the need for distributing clients’ account information to the application providers and achieving forward security. This paper efficiently addresses these challenges by devising a scalable certificateless remote authentication protocol with anonymity and forward security for WBANs. Different from the previous protocols in this field, our protocol not only provides mutual authentication, session key establishment, anonymity, unlinkability, and nonrepudiation, but also achieves forward security, key escrow resilience, and scalability. Performance evaluation demonstrates that compared with the most efficient ID-based remote anonymous authentication protocol, our protocol reduces at least 52.6% and 17.6% of the overall running time and communication overhead, respectively, and the reduction in the computation cost and communication overhead achieves at least 73.8% and 55.8%, respectively, compared with up-to-date certificateless remote authentication protocol with anonymity.