tff.federated_secure_sum

Computes a sum at tff.SERVER of a value placed on the tff.CLIENTS.

This function computes a sum such that it should not be possible for the server to learn any clients individual value. The specific algorithm and mechanism used to compute the secure sum may vary depending on the target runtime environment the computation is compiled for or executed on. See https://research.google/pubs/pub47246/ for more information.

Not all executors support tff.federated_secure_sum(); consult the documentation for the specific executor or executor stack you plan on using for the specific of how it's handled by that executor.

The bitwidth argument represents the bitwidth of the aggregand, that is the bitwidth of the input value. The federated secure sum bitwidth (i.e., the bitwidth of the sum of the input values over all clients) will be a function of this bitwidth and the number of participating clients.

Example:

value = tff.federated_value(1, tff.CLIENTS)
result = tff.federated_secure_sum(value, 2)

value = tff.federated_value([1, 1], tff.CLIENTS)
result = tff.federated_secure_sum(value, [2, 4])

value = tff.federated_value([1, [1, 1]], tff.CLIENTS)
result = tff.federated_secure_sum(value, [2, [4, 8]])

value An integer value of a TFF federated type placed at the tff.CLIENTS, in the range [0, 2^bitwidth - 1].
bitwidth An integer or nested structure of integers. For each tensor in value, bitwidth must contain exactly one corresponding integer.

A representation of the sum of the member constituents of value placed on the tff.SERVER.

TypeError if the argument is not a federated TFF value placed at tff.CLIENTS.