A way to get per-party random cint/regint in python

[5721309]

I've searched the documentation but couldn't find any function that generates personal random values for parties. There are methods for regint and cint called get_random but the documentation says they are insecure and public. So I assume those values are 1) synchronized between parties when generated; 2) synchronization happens without communication but because values are predictable for every party. Are my assumptions correct? What is the correct way to generate random personal regint/cint for each party?

[mkskeller]

Your assumptions are correct. There is no way to generate such values in the virtual machine/at the Python level. This is done at the C++ level because it is a protocol functionality rather than a protocol-independent arithmetic black box functionality. You could use sint.get_random_int().reveal_to() or sint.get_random_input_mask() as a workaround.

[5721309]

Thank you for reply! Do I understand it correctly that high-level programs are not intended for arbitrary MPC functionality but just for those that do arithmetic or boolean computations in non-reactive way? I mean if my functionality is defined in such a way that inputs from parties have to happen multiple times during computation (they could depend on result of a previous phase), then I should switch to C++ part of MP-SPDZ?

[mkskeller]

Yes. You can invoke high-level functionality from C++: https://mp-spdz.readthedocs.io/en/latest/function-export.html

[5721309]

Understood. Thank you!