Yeah. ‘Working’ might be a generous description, but I implemented several working methods - like keyforamount, swapforamount, mint/bolt11foramount. I stopped when I was told it was a bad idea, but it greatly simplified the proof management and payment.


I hacked it all in nutshell Cashu mint. 

Proof of work is in this branch below. Bottom line, I was successful in deriving the public/private key for any arbitrary amount and issuing the promises. 


https://github.com/trbouma/cashu/tree/amount_key 

 Yeah but that's the easy mode with broken privacy. 

 I was just proving the math worked. Didn’t get as far as working on privacy implications. Could easily be addressed  by a wallet by breaking an amount into the sum of two random components, etc. Anyway, very keen to see this idea is still alive. 

 No, the issue is that once you have individual keys for every amount everything becomes easily trackable. 

 Understand. That’s why I stuck with the power of 2 amounts. A bit of a pain to manage for arbitrary amounts, but I got that all working in my wallet implementation, so no longer an issue. I am intrigued on the new approach, though, and keen to learn more!