Yevgeniy Dodis Michael J. Freedman Stanislaw Jarecki Shabsi Walfish Optimal Signcryption from Any Trapdoor Permutation. 20 2004 2004 IACR Cryptology ePrint Archive http://eprint.iacr.org/2004/020 db/journals/iacr/iacr2004.html#DodisFJW04