diff --git a/backends/concrete-cpu/implementation/include/concrete-cpu.h b/backends/concrete-cpu/implementation/include/concrete-cpu.h
index a79acdc69..8d99db881 100644
--- a/backends/concrete-cpu/implementation/include/concrete-cpu.h
+++ b/backends/concrete-cpu/implementation/include/concrete-cpu.h
@@ -177,7 +177,8 @@ void concrete_cpu_decompress_seeded_lwe_bootstrap_key_u64(uint64_t *lwe_bsk,
                                                           size_t output_glwe_dimension,
                                                           size_t decomposition_level_count,
                                                           size_t decomposition_base_log,
-                                                          struct Uint128 compression_seed);
+                                                          struct Uint128 compression_seed,
+                                                          Parallelism parallelism);
 
 void concrete_cpu_decompress_seeded_lwe_ciphertext_u64(uint64_t *lwe_out,
                                                        const uint64_t *seeded_lwe_in,
@@ -190,7 +191,8 @@ void concrete_cpu_decompress_seeded_lwe_keyswitch_key_u64(uint64_t *lwe_ksk,
                                                           size_t output_lwe_dimension,
                                                           size_t decomposition_level_count,
                                                           size_t decomposition_base_log,
-                                                          struct Uint128 compression_seed);
+                                                          struct Uint128 compression_seed,
+                                                          Parallelism parallelism);
 
 void concrete_cpu_decrypt_glwe_ciphertext_u64(const uint64_t *glwe_sk,
                                               uint64_t *output,
diff --git a/backends/concrete-cpu/implementation/src/c_api/bootstrap.rs b/backends/concrete-cpu/implementation/src/c_api/bootstrap.rs
index 82026466d..717b391c1 100644
--- a/backends/concrete-cpu/implementation/src/c_api/bootstrap.rs
+++ b/backends/concrete-cpu/implementation/src/c_api/bootstrap.rs
@@ -179,6 +179,8 @@ pub unsafe extern "C" fn concrete_cpu_decompress_seeded_lwe_bootstrap_key_u64(
     decomposition_level_count: usize,
     decomposition_base_log: usize,
     compression_seed: Uint128,
+    // parallelism
+    parallelism: Parallelism,
 ) {
     nounwind(|| {
         let mut output_bsk = LweBootstrapKey::from_container(
@@ -217,11 +219,20 @@ pub unsafe extern "C" fn concrete_cpu_decompress_seeded_lwe_bootstrap_key_u64(
             CompressionSeed { seed },
             CiphertextModulus::new_native(),
         );
-
-        decompress_seeded_lwe_bootstrap_key::<_, _, _, SoftwareRandomGenerator>(
-            &mut output_bsk,
-            &input_bsk,
-        )
+        match parallelism {
+            Parallelism::No => {
+                decompress_seeded_lwe_bootstrap_key::<_, _, _, SoftwareRandomGenerator>(
+                    &mut output_bsk,
+                    &input_bsk,
+                )
+            }
+            Parallelism::Rayon => {
+                par_decompress_seeded_lwe_bootstrap_key::<_, _, _, SoftwareRandomGenerator>(
+                    &mut output_bsk,
+                    &input_bsk,
+                )
+            }
+        }
     });
 }
 
diff --git a/backends/concrete-cpu/implementation/src/c_api/keyswitch.rs b/backends/concrete-cpu/implementation/src/c_api/keyswitch.rs
index 6c9c9915f..abc5c5246 100644
--- a/backends/concrete-cpu/implementation/src/c_api/keyswitch.rs
+++ b/backends/concrete-cpu/implementation/src/c_api/keyswitch.rs
@@ -5,6 +5,7 @@ use tfhe::core_crypto::prelude::*;
 use super::csprng::new_dyn_seeder;
 use super::types::{EncCsprng, Uint128};
 use super::utils::nounwind;
+use crate::c_api::types::Parallelism;
 
 #[no_mangle]
 pub unsafe extern "C" fn concrete_cpu_init_lwe_keyswitch_key_u64(
@@ -128,6 +129,8 @@ pub unsafe extern "C" fn concrete_cpu_decompress_seeded_lwe_keyswitch_key_u64(
     decomposition_level_count: usize,
     decomposition_base_log: usize,
     compression_seed: Uint128,
+    // parallelism
+    parallelism: Parallelism,
 ) {
     nounwind(|| {
         let mut output_ksk = LweKeyswitchKey::from_container(
@@ -161,11 +164,20 @@ pub unsafe extern "C" fn concrete_cpu_decompress_seeded_lwe_keyswitch_key_u64(
             CompressionSeed { seed },
             CiphertextModulus::new_native(),
         );
-
-        decompress_seeded_lwe_keyswitch_key::<_, _, _, SoftwareRandomGenerator>(
-            &mut output_ksk,
-            &input_ksk,
-        )
+        match parallelism {
+            Parallelism::No => {
+                decompress_seeded_lwe_keyswitch_key::<_, _, _, SoftwareRandomGenerator>(
+                    &mut output_ksk,
+                    &input_ksk,
+                )
+            }
+            Parallelism::Rayon => {
+                par_decompress_seeded_lwe_keyswitch_key::<_, _, _, SoftwareRandomGenerator>(
+                    &mut output_ksk,
+                    &input_ksk,
+                )
+            }
+        }
     });
 }
 
diff --git a/compilers/concrete-compiler/compiler/lib/Common/Keys.cpp b/compilers/concrete-compiler/compiler/lib/Common/Keys.cpp
index 64f04cb2e..e5adfeb83 100644
--- a/compilers/concrete-compiler/compiler/lib/Common/Keys.cpp
+++ b/compilers/concrete-compiler/compiler/lib/Common/Keys.cpp
@@ -233,7 +233,7 @@ void LweBootstrapKey::decompress() {
     concrete_cpu_decompress_seeded_lwe_bootstrap_key_u64(
         buffer->data(), seededBuffer->data() + 2, params.getInputLweDimension(),
         params.getPolynomialSize(), params.getGlweDimension(),
-        params.getLevelCount(), params.getBaseLog(), seed);
+        params.getLevelCount(), params.getBaseLog(), seed, Parallelism::Rayon);
     decompressed = true;
     return;
   }
@@ -353,7 +353,7 @@ void LweKeyswitchKey::decompress() {
     concrete_cpu_decompress_seeded_lwe_keyswitch_key_u64(
         buffer->data(), seededBuffer->data() + 2, params.getInputLweDimension(),
         params.getOutputLweDimension(), params.getLevelCount(),
-        params.getBaseLog(), seed);
+        params.getBaseLog(), seed, Parallelism::Rayon);
     decompressed = true;
     return;
   }