key_switch_ext: Steps of hybrid key switching

In openfhe.R: R Interface to the 'OpenFHE' Fully Homomorphic Encryption Library

Steps of hybrid key switching

Description

Hybrid key switching works in an extended basis P*Q and comes back to Q at the end. These functions expose two of its steps, for code that hoists or defers them (CKKS). key_switch_ext() takes a ciphertext to the extended basis, multiplying its elements by P; with add_first = FALSE the first element of the result is left at zero. key_switch_down_first_element() brings only the first element back to Q and returns it as a ring element. key_switch_down() brings a whole ciphertext back.

Usage

key_switch_ext(ct, add_first)

key_switch_down_first_element(ct)

Arguments

ct	A Ciphertext.
add_first	Logical.

Value

key_switch_ext(): a Ciphertext in the extended basis. key_switch_down_first_element(): a DCRTPoly.

openfhe.R documentation built on Nov. 13, 2026, 5:07 p.m.