As a follow up to the Q/A session:
Small Quantum Signatures - Reality check needed
I have implemented the discussed idea for a new short-quantum-safe signature system using fast-forwarding hash. It creates 32 byte public keys and 129 byte signatures. It is as good as I could get it in the little time I had available.
I have uploaded the source code to GitHub (Java) under MIT licence for the benefit of crypto exchange.
My question then is : are there any obvious errors with the algorithm I have chosen to provide the fast-forwarding function?
I wouldn't mind forwarding this on to Bernstein etc so they can also take a crack at it - however if there are any obvious issues that I need to correct first - would appreciate knowing!