1. Encryption of pictures and shapes by random grids;Kafri;Opt. Lett.,1987
2. M. Naor, A. Shamir, Visual cryptography, in: A. De Santis (Ed.), Advances in Cryptology: Eurpocrypt’94, Lecture Notes in Computer Science, vol. 950, 1995, pp. 1–12.
3. Visual cryptography for general access structures;Ateniese;Inf. Comput.,1996
4. S. Droste, New results on visual cryptography, in: N. Koblitz (Ed.), Advances in Cryptology: CRYPTO’96, Lecture Notes in Computer Science, vol. 1109, 1996, pp. 401–415.
5. M. Naor, B. Pinkas, Visual authentication and identification, in: B.S. Kaliski Jr. (Ed.), Advances in Cryptology: CRYPTO’97, Lecture Notes in Computer Science, vol. 1294, 1997, pp. 322–336.