abenc_dacmacs_yj14

DAC-MACS: Data Access Control for Multi-Authority Cloud Storage (YJ14)

Authors: Kan Yang, Xiaohua Jia

Title: “DAC-MACS: Effective Data Access Control for Multi-Authority Cloud Storage Systems”

Published in: Security for Cloud Storage Systems - SpringerBriefs in Computer Science, 2014

Available from: http://link.springer.com/chapter/10.1007/978-1-4614-7873-7_4

Notes: Multi-authority scheme with efficient attribute revocation

Scheme Properties

• Type: ciphertext-policy attribute-based encryption (public key)

• Setting: Pairing groups

• Assumption: Decisional Bilinear Diffie-Hellman

Implementation

Authors:

artjomb

Date:

07/2014

class abenc_dacmacs_yj14.DACMACS(groupObj)

Bases: object

ctupdate(GPP, CT, attribute, CUK)

Updates the cipher-text using the update key, because of the revoked attribute (executed by cloud provider)

decrypt(CT, TK, z)

Decrypts the content(-key) from the cipher-text using the token and the user secret key (executed by user/content consumer)

encrypt(GPP, policy_str, k, authority)

Generate the cipher-text from the content(-key) and a policy (executed by the content owner)

generateTK(GPP, CT, UASK, g_u)

Generates a token using the user’s attribute secret keys to offload the decryption process (executed by cloud provider)

group

Prime order group

keygen(GPP, authority, attribute, userObj, USK=None)

Generate user keys for a specific attribute (executed on attribute authority)

registerUser(GPP)

Generate user keys (executed by the user).

setup()

Global Setup (executed by CA)

setupAuthority(GPP, authorityid, attributes, authorities)

Generate attribute authority keys (executed by attribute authority)

skupdate(USK, attribute, KUK)

Updates the user attribute secret key for the specified attribute (executed by non-revoked user)

ukeygen(GPP, authority, attribute, userObj)

Generate update keys for users and cloud provider (executed by attribute authority?)

abenc_dacmacs_yj14.basicTest()

abenc_dacmacs_yj14.revokedTest()

abenc_dacmacs_yj14.test()