A Low-Cost Key Derivation Scheme for Hierarchy-Based Access

Abstract

In current content delivery service, contents are usually encrypted for access control mechanism, so several key distribution schemes have been proposed. In this paper, we propose a new key derivation scheme for hierarchy-based access control. We assume that content consumers are listed in digraph structure, and all nodes are assigned seeds(prekeys) for decryption keys. All decryption keys are generated from initial keys assigned in root nodes, and a decryption key is derived from seeds of an ancestor node only using the one-way hash function. The proposed scheme includes conventional hierarchy-based key derivation schemes and can be implemented with low cost in computation for decryption keys because we do not need exponential calculations.

Access Control Methods Suitable for Stream Contents Delivery Cloud Services by Using Hash-Chain Based Key Derivation Schemes

“…In this efficient scheme [14], key data of nodes on a given directed acyclic graph are derivated from only m initial master keys and any node keys are derived from key data of only parent and ancestor nodes. A similar concept "one-way crosstrees" [5] defers this scheme because reference [14] considers and shows a countermeasure against collusion attacks by malicious nodes on a given directed graph.…”

“…A similar concept "one-way crosstrees" [5] defers this scheme because reference [14] considers and shows a countermeasure against collusion attacks by malicious nodes on a given directed graph.…”

“…It is assumed that all node keys are generated from m initial keys, and arbitrary node keys are derived from the node key of an ancestor node only using the one-way hash function. Reference [14] proposes the optimal constructions with the main theorem about the optimum of parameter m. Note that X-axis and Y-axis have the depth d x , d y respectively. We can identify this access structure as a lattice graph L dx,dy .…”

CLOUD SHREDDER: Removing the Laptop On-road Data Disclosure Threat in the Cloud Computing Era

“…[12] [13] The key is never retained on the hard drive, so the attacker can not obtain it without deriving from the password again. The extra time cost (e.g., 1 second) by once key derivation operation is acceptable when the legitimate user activates Cloud Shredder, but the extra time cost will be accumulated to a significant value when the attacker carries out brutal force trial on the password.…”