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Specialist Task Force 529:
Attribute Based Encryption - Common protocol for data access control for Cloud, Mobile and IoT

Who we are:

 

Team leader:
  • Giovanni Bartolomeo, CNIT, giovanni.bartolomeo AT uniroma2.it
Team Members:
  • Christoph Striecks, AIT, christoph.striecks AT ait.ac.at
  • François Ambrosini, IBIT, francois.ambrosini AT famb.info
  • Claudio Pisa, CNIT, claudio.pisa AT uniroma2.it
  • Pascal Paillier, CryptoExperts, pascal.paillier AT cryptoexperts.com

What we do

We bring new encryption techniques to attribute-based access control.

Encryption is widely used to protect data confidentiality in untrusted environments. In traditional public key encryption, the sender must know in advance the public key of each individual to whom the data should be disclosed. Only the recipient in possession of the matching private key is able to decrypt the message. Where a message has to be transmitted to several parties, it has to be encrypted separately for each party. 

Such encryption schemes provide a simple solution to access control - allowing only the sender and recipient access to the message. But, in general, encryption schemes are not of themselves considered as access control schemes, but part of.

To provide secure access control, therefore, traditional encryption schemes are sided with a software infrastructure. The general structure adopted today is based on access control policies. In Attribute Based Access Control (ABAC), in particular, policies use attributes provided to parties by one or more authorities. Policies are evaluated by a Policy Decision Point (PDP), and enforced through a Policy Enforcement Point (PEP) which permits or denies access to a resource. Several threats may compromise the software infrastructure and the Policy Enforcement Point in particular.

Attribute Based Encryption (ABE) is a cryptographic scheme that provides a level of protection similar to ABAC but exclusively leveraging on cryptographic algorithms, without relying on a software based PEP. In practice, ABE mathematically moves the authorisation decision from the functional elements of the access control system (PDP, PEP) to the protected data itself, i.e., the ciphertext, or to the cryptography keys, i.e., the private keys.

STF 529 is tasked to provide an ETSI Technical Specification to define a standard toolkit for ABE. One challenge is to map ABE-based access control to traditional access control so that the former can be a superset of the latter in terms of capabilities. A second challenge is to accommodate both the Ciphertext-Policy and the Key-Policy variants of ABE, which handle access control differently and consequently address different but similarly important use cases.

For more details, see our Terms of Reference

Why we do it

Benefits for Vendors and Providers

The results of STF 529 will provide new ways of enforcing access control, in a manner that will help compliance to privacy regulations.

Understanding the connection between privacy protection and interoperability, the General Data Protection Regulation (GDPR) has explicitly acknowledged a right to “data portability” to citizens and customers of the EU Digital Single Market. Member States have started to promote interoperability agreements for the Public and private sector (eID, eDelivery, eSignature, eInvoicing, eTranslation). However, achieving full interoperability without addressing data protection mechanisms and access control in particular might be difficult! 

To date, existing mechanisms are primarily focused on legacy enterprise solutions. ABE might become a core capability to deploy fine-grained data access control solutions to Cloud and Internet of Things platforms. The mathematically enforced access controls, and mathematically verifiable resilience to a large class of threats offers additional strategies to designers. Vendors and providers will be able to enhance the capabilities to their existing solutions.

The release of a standardized protocol may unlock citizen and customer data from proprietary platforms, encouraging interoperability and controlled flow of data, which is vital for the rising transnational Digital Single Market. 

At the same time, citizens’ trust in Cloud services may increase with the provision of a transparent, uniform and mathematically proved protocol for governing access to their data. ABE is also well suited for offline authentication and protection of data at rest while allowing flexible issuance of access control policies, making it an ideal candidate to support data-driven business models with strong confidentiality and privacy requirements, as is the case in the IoT domain.

How we do it

The STF runs under the supervision of a Steering Group from the ETSI Technical Committee CYBER (the Steering Group is open to all TC CYBER delegates) and coordinates the work with the ETSI Centre for Testing and Interoperability (CTI).

The STF is made of cryptographers, industry experts and researchers. We apply the usual stage-1/2/3 method (use cases and architecture, requirements, technical specification). The binding between Attribute-Based Encryption and traditional access control is at the core of the work, as well as adaptation of traditional PKIs for ABE key distribution. We monitor and leverage the work of the research community related to ABE, as well as the work done in ISO, oneM2M and other standardisation fora related to privacy and ontologies.

The STF performs its work by face-to-face and remote sessions. Experts perform a significant part of their work at their own premises using their own means.

Biweekly calls restricted to STF experts are held regularly to synchronize the work from remote locations. A mailing list is active for discussion. 

Deliverables

The STF will produce one deliverable (expected publication: Q1/2018) titled “TS 173 532 CYBER; Attribute Based Encryption for Attribute Based Access Control”.

The corresponding work item number is DTS/CYBER-0025.

Time plan

The STF runs from March 2017 to January 2018. The following milestones have been agreed:

     Code              Task / Milestone / Deliverable                                                                                                            Target date                                     
   M0  Appointment of the STF Steering group at CYBER#9 (13-15 Feb 2017).  06 Mar 2017
Achieved
    A  TS draft reviewed at CYBER#10 (31 May - 02 June 2017) CYBER#10

 CYBER#10
31 May - 02 June 2017
Achieved
    B Experts' work official presentation to stakeholders during ETSI Security week
 (5G ENSURE workshop). 
 June 2017
Achieved
    C TS stable draft reviewed at CYBER#11 (25/27 Sept 2017)
 CYBER#11
25-27 Sept 2017
Achieved
    D TS Final deliverable and Final Report to be approved by TC CYBER
ETSI TS 103 532 is available here 
 CYBER#12
07-09 Feb. 2018
Achieved

 

How to contact us

To contact us, please send an email to the STF leader: giovanni.bartolomeo AT uniroma2.it

This information is based upon STF working assumptions.

The views expressed do not necessarily represent the position of ETSI in this context.