Add glwe blind selection

poulpy-schemes/src/tfhe/bdd_arithmetic/blind_selection.rs

@@ -0,0 +1,90 @@
+use std::collections::HashMap;
+
+use poulpy_core::{
+    GLWECopy, GLWEDecrypt, ScratchTakeCore,
+    layouts::{GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWEToMut, GLWEToRef},
+};
+use poulpy_hal::layouts::{Backend, Module, Scratch, ZnxZero};
+
+use crate::tfhe::bdd_arithmetic::{Cmux, GetGGSWBit, UnsignedInteger};
+
+impl<T: UnsignedInteger, BE: Backend> GLWEBlinSelection<T, BE> for Module<BE> where Self: GLWECopy + Cmux<BE> + GLWEDecrypt<BE> {}
+
+pub trait GLWEBlinSelection<T: UnsignedInteger, BE: Backend>
+where
+    Self: GLWECopy + Cmux<BE> + GLWEDecrypt<BE>,
+{
+    fn glwe_blind_selection_tmp_bytes<R, K>(&self, res_infos: &R, k_infos: &K) -> usize
+    where
+        R: GLWEInfos,
+        K: GGSWInfos,
+    {
+        self.cmux_tmp_bytes(res_infos, res_infos, k_infos) + GLWE::bytes_of_from_infos(res_infos)
+    }
+
+    #[allow(clippy::too_many_arguments)]
+    fn glwe_blind_selection<R, A, K>(
+        &self,
+        res: &mut R,
+        mut a: HashMap<usize, &mut A>,
+        fhe_uint: &K,
+        bit_rsh: usize,
+        bit_mask: usize,
+        scratch: &mut Scratch<BE>,
+    ) where
+        R: GLWEToMut,
+        A: GLWEToMut + GLWEToRef,
+        K: GetGGSWBit<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        assert!(bit_rsh + bit_mask <= T::BITS as usize);
+
+        let res: &mut GLWE<&mut [u8]> = &mut res.to_mut();
+
+        for i in 0..bit_mask {
+            let t: usize = 1 << (bit_mask - i - 1);
+
+            let bit: &GGSWPrepared<&[u8], BE> = &fhe_uint.get_bit(bit_rsh + bit_mask - i - 1); // MSB -> LSB traversal
+
+            for j in 0..t {
+                let hi: Option<&mut A> = a.remove(&j);
+                let lo: Option<&mut A> = a.remove(&(j + t));
+
+                match (lo, hi) {
+                    (Some(lo), Some(hi)) => {
+                        self.cmux_inplace(lo, hi, bit, scratch);
+                        a.insert(j, lo);
+                    }
+
+                    (Some(lo), None) => {
+                        let (mut zero, scratch_1) = scratch.take_glwe(res);
+                        zero.data_mut().zero();
+                        self.cmux_inplace(lo, &zero, bit, scratch_1);
+                        a.insert(j, lo);
+                    }
+
+                    (None, Some(hi)) => {
+                        let (mut zero, scratch_1) = scratch.take_glwe(res);
+                        zero.data_mut().zero();
+                        self.cmux_inplace(&mut zero, hi, bit, scratch_1);
+                        self.glwe_copy(hi, &zero);
+                        a.insert(j, hi);
+                    }
+
+                    (None, None) => {
+                        // No low or high branch — nothing to insert
+                        // leave empty; future iterations will combine actual ciphertexts
+                    }
+                }
+            }
+        }
+
+        let out: Option<&mut A> = a.remove(&0);
+
+        if let Some(out) = out {
+            self.glwe_copy(res, out);
+        } else {
+            res.data_mut().zero();
+        }
+    }
+}

poulpy-schemes/src/tfhe/bdd_arithmetic/mod.rs

@@ -1,5 +1,6 @@
 mod bdd_2w_to_1w;
 mod blind_rotation;
+mod blind_selection;
 mod ciphertexts;
 mod circuits;
 mod eval;
@@ -7,6 +8,7 @@ mod key;
 
 pub use bdd_2w_to_1w::*;
 pub use blind_rotation::*;
+pub use blind_selection::*;
 pub use ciphertexts::*;
 pub(crate) use circuits::*;
 pub use eval::*;

poulpy-schemes/src/tfhe/bdd_arithmetic/tests/fft64_ref.rs

@@ -6,7 +6,7 @@ use crate::tfhe::{
     bdd_arithmetic::tests::test_suite::{
         TestContext, test_bdd_add, test_bdd_and, test_bdd_or, test_bdd_prepare, test_bdd_sll, test_bdd_slt, test_bdd_sltu,
         test_bdd_sra, test_bdd_srl, test_bdd_sub, test_bdd_xor, test_fhe_uint_splice_u8, test_fhe_uint_splice_u16,
-        test_glwe_to_glwe_blind_rotation, test_scalar_to_ggsw_blind_rotation,
+        test_glwe_blind_selection, test_glwe_to_glwe_blind_rotation, test_scalar_to_ggsw_blind_rotation,
     },
     blind_rotation::CGGI,
 };
@@ -14,6 +14,11 @@ use crate::tfhe::{
 static TEST_CONTEXT_CGGI_FFT64_REF: LazyLock<TestContext<CGGI, FFT64Ref>> =
     LazyLock::new(|| TestContext::<CGGI, FFT64Ref>::new());
 
+#[test]
+fn test_glwe_blind_selection_fft64_ref() {
+    test_glwe_blind_selection(&TEST_CONTEXT_CGGI_FFT64_REF)
+}
+
 #[test]
 fn test_fhe_uint_splice_u8_fft64_ref() {
     test_fhe_uint_splice_u8(&TEST_CONTEXT_CGGI_FFT64_REF)

poulpy-schemes/src/tfhe/bdd_arithmetic/tests/test_suite/glwe_blind_selection.rs

@@ -0,0 +1,147 @@
+use std::collections::HashMap;
+
+use poulpy_core::{
+    GGSWEncryptSk, GLWEDecrypt, GLWEEncryptSk, ScratchTakeCore,
+    layouts::{
+        Base2K, Dnum, Dsize, GGSWLayout, GGSWPreparedFactory, GLWE, GLWELayout, GLWEPlaintext, GLWESecretPrepared,
+        GLWESecretPreparedFactory, Rank, TorusPrecision,
+    },
+};
+use poulpy_hal::{
+    api::{ModuleNew, ScratchOwnedAlloc, ScratchOwnedBorrow},
+    layouts::{Backend, Module, Scratch, ScratchOwned},
+    source::Source,
+};
+use rand::RngCore;
+
+use crate::tfhe::{
+    bdd_arithmetic::{
+        FheUintPrepared, GLWEBlinSelection,
+        tests::test_suite::{TEST_BASE2K, TEST_RANK, TestContext},
+    },
+    blind_rotation::BlindRotationAlgo,
+};
+
+pub fn test_glwe_blind_selection<BRA: BlindRotationAlgo, BE: Backend>(test_context: &TestContext<BRA, BE>)
+where
+    Module<BE>: ModuleNew<BE>
+        + GLWESecretPreparedFactory<BE>
+        + GGSWPreparedFactory<BE>
+        + GGSWEncryptSk<BE>
+        + GLWEBlinSelection<u32, BE>
+        + GLWEDecrypt<BE>
+        + GLWEEncryptSk<BE>,
+    ScratchOwned<BE>: ScratchOwnedAlloc<BE> + ScratchOwnedBorrow<BE>,
+    Scratch<BE>: ScratchTakeCore<BE>,
+{
+    let module: &Module<BE> = &test_context.module;
+    let sk_glwe_prep: &GLWESecretPrepared<Vec<u8>, BE> = &test_context.sk_glwe;
+
+    let base2k: Base2K = TEST_BASE2K.into();
+    let rank: Rank = TEST_RANK.into();
+    let k_glwe: TorusPrecision = TorusPrecision(26);
+    let k_ggsw: TorusPrecision = TorusPrecision(39);
+    let dnum: Dnum = Dnum(3);
+
+    let glwe_infos: GLWELayout = GLWELayout {
+        n: module.n().into(),
+        base2k,
+        k: k_glwe,
+        rank,
+    };
+    let ggsw_infos: GGSWLayout = GGSWLayout {
+        n: module.n().into(),
+        base2k,
+        k: k_ggsw,
+        rank,
+        dnum,
+        dsize: Dsize(1),
+    };
+
+    let mut source: Source = Source::new([6u8; 32]);
+    let mut source_xa: Source = Source::new([2u8; 32]);
+    let mut source_xe: Source = Source::new([3u8; 32]);
+
+    let mut scratch: ScratchOwned<BE> = ScratchOwned::alloc(1 << 22);
+
+    let mut res: GLWE<Vec<u8>> = GLWE::alloc_from_infos(&glwe_infos);
+
+    let k: u32 = source.next_u32();
+
+    let mut k_enc_prep: FheUintPrepared<Vec<u8>, u32, BE> =
+        FheUintPrepared::<Vec<u8>, u32, BE>::alloc_from_infos(module, &ggsw_infos);
+    k_enc_prep.encrypt_sk(
+        module,
+        k,
+        sk_glwe_prep,
+        &mut source_xa,
+        &mut source_xe,
+        scratch.borrow(),
+    );
+
+    let digit = 5;
+    let mask: u32 = (1 << digit) - 1;
+
+    // Starting bit
+    let mut bit_start: usize = 0;
+
+    let mut data = vec![0i64; 1 << digit];
+    data.iter_mut().enumerate().for_each(|(i, x)| *x = i as i64);
+
+    for _ in 0..32_usize.div_ceil(digit) {
+        let mut pt: GLWEPlaintext<Vec<u8>> = GLWEPlaintext::alloc_from_infos(&glwe_infos);
+
+        let mut cts_map: HashMap<usize, &mut GLWE<Vec<u8>>> = HashMap::new();
+        let mut cts: Vec<GLWE<Vec<u8>>> = Vec::new();
+
+        for value in data.iter().take(1 << digit) {
+            pt.encode_coeff_i64(*value, TorusPrecision(base2k.as_u32()), 0);
+            let mut ct = GLWE::alloc_from_infos(&glwe_infos);
+            ct.encrypt_sk(
+                module,
+                &pt,
+                sk_glwe_prep,
+                &mut source_xa,
+                &mut source_xe,
+                scratch.borrow(),
+            );
+            cts.push(ct);
+        }
+
+        for (i, ct) in cts.iter_mut().enumerate() {
+            if i.is_multiple_of(3) {
+                cts_map.insert(i, ct);
+            }
+        }
+
+        // How many bits to take
+        let bit_size: usize = (32 - bit_start).min(digit);
+
+        module.glwe_blind_selection(
+            &mut res,
+            cts_map,
+            &k_enc_prep,
+            bit_start,
+            bit_size,
+            scratch.borrow(),
+        );
+
+        res.decrypt(module, &mut pt, sk_glwe_prep, scratch.borrow());
+
+        let idx = ((k >> bit_start) & mask) as usize;
+        if idx.is_multiple_of(3) {
+            assert_eq!(0, pt.decode_coeff_i64(TorusPrecision(base2k.as_u32()), 0));
+        } else {
+            assert_eq!(
+                data[idx],
+                pt.decode_coeff_i64(TorusPrecision(base2k.as_u32()), 0)
+            );
+        }
+
+        bit_start += digit;
+
+        if bit_start >= 32 {
+            break;
+        }
+    }
+}

poulpy-schemes/src/tfhe/bdd_arithmetic/tests/test_suite/mod.rs

@@ -3,6 +3,7 @@ mod and;
 mod fheuint;
 mod ggsw_blind_rotations;
 mod glwe_blind_rotation;
+mod glwe_blind_selection;
 mod or;
 mod prepare;
 mod sll;
@@ -18,6 +19,7 @@ pub use and::*;
 pub use fheuint::*;
 pub use ggsw_blind_rotations::*;
 pub use glwe_blind_rotation::*;
+pub use glwe_blind_selection::*;
 pub use or::*;
 use poulpy_hal::{
     api::{ModuleNew, ScratchOwnedAlloc, ScratchOwnedBorrow},