Quantum Watermarking and Extraction for handwritten signature

In this paper, we propose quantum watermarking and extraction algorithms for handwritten signature. Handwritten signature image can be transmitted from source to target securely over untrusted network by using this scheme. It appears that the laws of physics are completely reversible. That is, from any physical process we can always deduce the inputs from the outputs. Classical computers would at first appear to violate this law as we can easily create functions on classical computers that are not reversible. In quantum computers, we cannot allow this situation to occur. Here, in this work we have implemented the reversible quantum gates and according to the definition of reversible gates, we have used an equal number of inputs and outputs in our design scheme and successfully tested in our modern classical computers. This work will show the new research area in the line of quantum watermarking.