From ba984c2537d4c7641bcf726b647ab60535aa7257 Mon Sep 17 00:00:00 2001
From: J-B Orfila <jb.orfila@zama.ai>
Date: Fri, 2 Dec 2022 15:34:23 +0100
Subject: [PATCH] feat(core): blind rotate binding

---
 .../lwe_programmable_bootstrapping.rs         | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tfhe/src/core_crypto/algorithms/lwe_programmable_bootstrapping.rs b/tfhe/src/core_crypto/algorithms/lwe_programmable_bootstrapping.rs
index bf07f57c4..54182eb12 100644
--- a/tfhe/src/core_crypto/algorithms/lwe_programmable_bootstrapping.rs
+++ b/tfhe/src/core_crypto/algorithms/lwe_programmable_bootstrapping.rs
@@ -3,11 +3,40 @@ use crate::core_crypto::commons::numeric::CastInto;
 use crate::core_crypto::commons::traits::*;
 use crate::core_crypto::entities::*;
 use crate::core_crypto::fft_impl::crypto::bootstrap::{bootstrap_scratch, FourierLweBootstrapKey};
+use crate::core_crypto::fft_impl::crypto::ggsw::cmux_scratch;
 use crate::core_crypto::fft_impl::math::fft::FftView;
 use crate::core_crypto::specification::parameters::*;
+use aligned_vec::CACHELINE_ALIGN;
 use concrete_fft::c64;
 use dyn_stack::{DynStack, SizeOverflow, StackReq};
 
+pub fn blind_rotate<Scalar, InputCont, OutputCont, KeyCont>(
+    input: &LweCiphertext<InputCont>,
+    lut: &mut GlweCiphertext<OutputCont>,
+    bsk: &FourierLweBootstrapKey<KeyCont>,
+    fft: FftView<'_>,
+    stack: DynStack<'_>,
+) where
+    // CastInto required for PBS modulus switch which returns a usize
+    Scalar: UnsignedTorus + CastInto<usize>,
+    InputCont: Container<Element = Scalar>,
+    OutputCont: ContainerMut<Element = Scalar>,
+    KeyCont: Container<Element = c64>,
+{
+    bsk.as_view()
+        .blind_rotate(lut.as_mut_view(), input.as_ref(), fft, stack);
+}
+
+/// Returns the required memory for [`blind_rotate`].
+pub fn blind_rotate_scratch<Scalar>(
+    glwe_size: GlweSize,
+    polynomial_size: PolynomialSize,
+    fft: FftView<'_>,
+) -> Result<StackReq, SizeOverflow> {
+    StackReq::try_new_aligned::<Scalar>(glwe_size.0 * polynomial_size.0, CACHELINE_ALIGN)?
+        .try_and(cmux_scratch::<Scalar>(glwe_size, polynomial_size, fft)?)
+}
+
 pub fn programmable_bootstrap_lwe_ciphertext<Scalar, InputCont, OutputCont, AccCont, KeyCont>(
     input: &LweCiphertext<InputCont>,
     output: &mut LweCiphertext<OutputCont>,