1. Warasart, M., Kuacharoen, P.: Paper-based document authentication using digital signature and QR code. In: 4th International Conference on Computer Engineering and Technology (ICCET) (2012)
2. Naor, M., Yung, M.: Universal one-way hash functions and their cryptographic applications. In: Proc. 21st STOC (1995)
3. Pappu, R.: Physical one-way functions. Phd thesis, Massachusets Instutute of Tecnhology (2001)
4. Merkle, R.C.: A Certified Digital Signature. Springer-Verlag (1998)
5. Rivest, R.L., Shamir, A., Adleman, L.: A Method for Obtaining Digital Signatures and Public-Key Cryptosystems (1997)