abenc_tbpre_lww14

Time-Based Proxy Re-Encryption (LWW14)

Authors: Qin Liu, Guojun Wang, Jie Wu

Title: “Time-based proxy re-encryption scheme for secure data sharing in a cloud environment”

Published in: Information Sciences, Volume 258, 2014

Available from: http://www.sciencedirect.com/science/article/pii/S0020025512006275

Notes: Time-based access control with proxy re-encryption for cloud storage

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_tbpre_lww14.TBPRE(groupObj)

Bases: object

decrypt(CT, user, term=None)

Decrypts the content(-key) from the cipher-text (executed by user/content consumer)

encrypt(PK, policy, F)

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

group

Prime order group

hashDate(H, time, s)

keygen(MK, PK, H, s, user, pubuser, attribute, time)

Generate user keys for a specific attribute (executed by CA)

policyTerm(user, policy)

reencrypt(PK, H, s, CT, currentTime)

Re-encrypts the cipher-text using the current time (executed by cloud service provider)

registerUser(PK, H)

Registers a user by id (executed by user)

setup(attributes)

Global Setup (executed by CA)

timeSuffices(timeRange, needle)

abenc_tbpre_lww14.basicTest()

abenc_tbpre_lww14.basicTest2()

Month-based attributes are used

abenc_tbpre_lww14.gcd(*numbers)

Return the greatest common divisor of the given integers

abenc_tbpre_lww14.lcm(numbers)

Return lowest common multiple.

abenc_tbpre_lww14.test()