Attribute-Based Encryption With Verifiable Outsourced Decryption
Attribute-based encryption (ABE) is a public-keybased one-to-many encryption that allows users to encrypt and decrypt data based on user attributes. A promising application of ABE is flexible access control of encrypted data stored in the cloud, using access polices and ascribed attributes associated with private keys and ciphertexts.One of themain efficiency drawbacks of the existing ABE schemes is that decryption involves expensive pairing operations and the number of such operations grows with the complexity of the access policy. Recently, Green et al. proposed an ABE system with outsourced decryption that largely eliminates the decryption overhead for users. In such a system, a user provides an untrusted server, say a cloud service provider, with a transformation key that allows the cloud to translate any ABE ciphertext satisfied by that user’s attributes or access policy into a simple ciphertext, and it only incurs a small computational overhead for the user to recover the plaintext from the transformed ciphertext. Security of an ABE system with outsourced decryption ensures that an adversary (including a malicious cloud) will not be able to learn anything about the encrypted message; however, it does not guarantee the correctness of the transformation done by the cloud. In this paper, we consider a new requirement of ABE with outsourced decryption: verifiability. Informally, verifiability guarantees that a user can efficiently check if the transformation is done correctly. We give the formal model of ABE with verifiable outsourced decryption and propose a concrete scheme. We prove that our new scheme is both secure and verifiable, without relying on random oracles. Finally, we show an implementation of our scheme and result of performance measurements, which indicates a significant reduction on computing resources imposed on users.
PROJECT OUTPUT VIDEO: (Click the below link to see the project output video):
Green et al. proposed an ABE system with outsourced decryption that largely eliminates the decryption overhead for users. In such a system, a user provides an untrusted server, say a cloud service provider, with a transformation key that allows the cloud to translate any ABE ciphertext satisfied by that user’s attributes or access policy into a simple ciphertext, and it only incurs a small computational overhead for the user to recover the plaintext from the transformed ciphertext.
DISADVANTAGES OF EXISTING SYSTEM:
One of the main efficiency drawbacks of the most existing ABE schemes is that decryption is expensive for resource-limited devices due to pairing operations, and the number of pairing operations required to decrypt a ciphertext grows with the complexity of the access policy. At the cost of security, only proven in a weak model (i.e., selective security), there exist several expressive ABE schemes where the decryption algorithm only requires a constant number of pairing computations.
In this paper, we first modify the original model of ABE with outsourced decryption in existing system to allow for verifiability of the transformations. After describing the formal definition of verifiability, we propose a new ABE model and based on this new model construct a concrete ABE scheme with verifiable outsourced decryption. Our scheme does not rely on random oracles.
ADVANTAGES OF PROPOSED SYSTEM:
üProposed scheme does not rely on random oracles
üThe scheme substantially reduced the computation time required for resource-limited devices to recover plaintexts.
üProcessor – Pentium –IV
üSpeed – 1.1 Ghz
üRAM – 256 MB(min)
üHard Disk – 20 GB
üKey Board – Standard Windows Keyboard
üMouse – Two or Three Button Mouse
üMonitor – SVGA
üOperating System : Windows XP
üProgramming Language : JAVA/J2EE.
üJava Version : JDK 1.6 & above.
üDatabase : MYSQL
Junzuo Lai, Robert H. Deng, Chaowen Guan, and Jian Weng, “Attribute-Based Encryption With Verifiable Outsourced Decryption”, IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY, VOL. 8, NO. 8, AUGUST 2013.