Privacy-preserving encryption scheme using DNA parentage test

Consider a scenario where a user's credential is related to his/her DNA sequences. This credential can be used to construct a confidential message, which is decipherable by someone who is a relative of the encryptor, i.e., the person who has enough close DNA sequences. We would like to have a system that provides privacy-preserving, in the sense that nobody will learn whether the encryptor is truly the ancestor of the recipient, except the fact whether the recipient can decrypt the given ciphertext or not. We present a system to realize this complex access control on encrypted data, such that the attributes used to describe a user's credential will determine a policy as to which recipient will be able to decrypt the provided ciphertext. We formalize the security model of our system against chosen ciphertext attacks and collusion attacks. Furthermore, we show an efficient and provably secure construction.