Fuyuki Kitagawa Ryo Nishimaki Keisuke Tanaka Obfustopia Built on Secret-Key Functional Encryption. 603-648 2018 EUROCRYPT (2) https://doi.org/10.1007/978-3-319-78375-8_20 conf/eurocrypt/2018-2 db/conf/eurocrypt/eurocrypt2018-2.html#KitagawaNT18