Are zkSNARKS practical? I'm considering using zkSNARKS for a project i'm building. I have some questions about the practicality of such algorithms:


Does a standard secure implementation exists?
What is the complexity for the generator, prover, and verifier procedures? What does it depend on?
Is it efficient in practice on normal computers (contrary to say homomorphic encryption, which has polynomial complexity but very inefficient in practice)? What are the results of profiling done on actual implementations?
Proof generation complexity is large but better than previous ideas.
For the verifier the complexity depends linearly on the size of the function the input and the output $O(|f|+|x|+|y|)$ where $y=f(x)$ the computation to be verified for a particular value security of the parameter.
The proof size is constant. 

For more details you can check the papers and implementations in http://www.scipr-lab.org. I think it is the best resource on the subject.