Adaptable ciphertext-policy attribute-based encryption

• Main Authors: LAI, Junzuo, DENG, Robert H., YANG, Yanjiang, WENG, Jian
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2013
• Subjects: Ciphertext; Policy attribute. Based encryption; Adaptability; Policy change; Information Security
• Online Access: https://ink.library.smu.edu.sg/sis_research/1950; https://ink.library.smu.edu.sg/context/sis_research/article/2949/viewcontent/Adaptableciphertext_policyattribute_basedencryption.pdf
• Institution: Singapore Management University

In this paper, we introduce a new cryptographic primitive, called adaptable ciphertext-policy attribute-based encryption (CP-ABE). Adaptable CP-ABE extends the traditional CP-ABE by allowing a semi-trusted proxy to modify a ciphertext under one access policy into ciphertexts of the same plaintext under any other access policies; the proxy, however, learns nothing about the underlying plaintext. With such “adaptability” possessed by the proxy, adaptable CP-ABE has many real world applications, such as handling policy changes in CP-ABE encryption of cloud data and outsourcing of CP-ABE encryption. Specifically, we first specify a formal model of adaptable CP-ABE; then, based on the CP-ABE scheme by Waters, we propose a concrete adaptable CP-ABE scheme and further prove its security under our security model.