Functional Encryption

Functional Encryption (FE) is a generalization of public-key encryption in which a decryption key allows a user to learn a function of the encrypted data. Briefly, in functional encryption system for a functionality F(.,.) an authority holding a master-secret key can generate a secret-key that has the right to compute the function F(.,.) on encrypted data. More precisely, using the secret-key the decryptor can compute F(.,.) from encryption of x. In contrast, an adversary gathers only negligible information about x which guarantees the security of the system. It is the generalization of several existing cryptographic primitives including Identity-Based Encryption (IBE) and Attribute-Based Encryption (ABE). For IBE, define F(k, x) to be equal to x when k corresponds to an identity that is allowed to decrypt, and ⟂otherwise. Similarly, for ABE, define F(k,x)=x when k encodes attributes with permission to decrypt and ⟂ otherwise.

Publication

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  • Subhranil Dutta, Tapas Pal and Ratna Dutta: Fully Secure Unbounded Zero Inner Product Encryption with Short Ciphertexts and Keys. In the Proceedings of the 15th International Conference on Provable and Practical Security. (ProvSec 2021)

  • Tapas Pal, Ratna Dutta: Non-zero Inner Product Encryption: Unrestricted Message Space and Chosen Ciphertext Security. In the Proceeding of the 18th International Conference on Security and Cryptography (SECRYPT 2021), July 6-8, 2021.