Attribute-Based Encryption With Efficient Verifiable Outsourced Decryption

摘要: Attribute-based encryption (ABE) with outsourced decryption not only enables fine-grained sharing of encrypted data, but also overcomes the efficiency drawback (in terms ciphertext size and cost) standard ABE schemes. In particular, an scheme allows a third party (e.g., cloud server) to transform into (short) El Gamal-type using public transformation key provided by user so that latter can be decrypted much more efficiently than former user. However, shortcoming original is correctness server’s cannot verified That is, end could cheated accepting wrong or maliciously transformed output. this paper, we first formalize security model verifiable introducing verification in output algorithm. Then, present approach convert any decryption. The new simple, general, almost optimal. Compared ABE, our neither increases user’s computation costs except some nondominant operations hash computations), nor expands adding value (which et al .’s ciphertext-policy decryption, provide detailed performance evaluation demonstrate advantages approach.