I suggest the following changes in the BIP 158 block filter API to make it future proof:
The request contains an additional parameter. The parameter indicates the false positivity rate of the requested filter. The server replies with the block filter that best matches the false positivity rate. For now, block filters with a single positivity rate will be implemented.
The response additionally contains the filter's parameters M and P.
The reason for this is that we cannot avoid using different parameters for filters in the future. The anonymous discovery using filters has the following disadvantage: The number of blocks downloaded due to false matches is linear (for small values) in the number of addresses that the user searches for. Since the number of addresses searched for by a user is constantly growing, we might have to introduce block filters with a lower false positivity rate in the future.
I suggest the following changes in the BIP 158 block filter API to make it future proof:
MandP.The reason for this is that we cannot avoid using different parameters for filters in the future. The anonymous discovery using filters has the following disadvantage: The number of blocks downloaded due to false matches is linear (for small values) in the number of addresses that the user searches for. Since the number of addresses searched for by a user is constantly growing, we might have to introduce block filters with a lower false positivity rate in the future.