Measuring size of bootstrapping keys

OpenFHE ports/wrappers
1

Hi,

I am trying to measure the size of the bootstrapping keys for different parameter sets using the python wrapper.

Currently, I am measuring them as follows:

auto_ser = SerializeEvalAutomorphismKeyString(BINARY, “”)

auto_size = len(auto_ser)

The problem is that with larger batchsize/ringdimension, the keys get really large. I have a lot of ram, but with the serialization the program essentially then consumes twice the RAM as before, which is too much for my system. I happen to also not have much disk space at the moment, so I’d like to avoid serializing to file.

Is there a way to serialize the automorphism keys for bootstrapping one after the other, or to determine the size of one of them and the number of keys to multiply with?

Thanks!

2

In C++, you can serialize each them individually if you access the map using GetEvalAutomorphismKeyMap. Then you can iterate through the STL map (for the desired key tag) using the standard C++ API for STL maps. You can also check the size of the map.

This is not directly exposed in openfhe-python, but such bindings could be added.