Editing Gottesman and Chuang Quantum Digital Signature (section)

==Properties==
*The public keys can be used only once.
*Only limited (T) distribution of public keys should be allowed, such that <math>T < L/n</math>, where quantum public key is an 'n' qubit state.
* Unlike some classical information-theoretic (unconditional security) schemes which require secure anonymous broadcast channel or noisy channel, which are hard to achieve resources, the quantum scheme provides information-theoretic security by only demanding plausible quantum channels and modest interaction between parties involved.
* The scheme is secure against forgery if <math>(1-\delta^2)(M-G)>c_2M</math>, where <math>G=2^{-(L-Tn)}2M</math> and <math>\delta</math> depends on public keys and hence, on quantum one way functions. <math>\delta\sim 0.9</math> for quantum fingerprint states; <math>\delta\sim 1/\sqrt{2}</math> for stabilizer states. For the method where one classical bit is represented by one qubit, which consists of the states <math>cos(j\theta)+sin(j\theta)</math>, for <math>\theta=\pi/2^L</math>, <math>\delta=cos(\theta)</math>.
* The Seller can successfully repudiate by probability, <math>p_{cheat}\sim O(d^{-M})</math>, for some <math>d>1</math>.