diff --git a/Optimized_Implementation/neon/CMakeLists.txt b/Optimized_Implementation/neon/CMakeLists.txt
index 9c39140..20a843f 100644
--- a/Optimized_Implementation/neon/CMakeLists.txt
+++ b/Optimized_Implementation/neon/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.5)
 project(less_neon)
 enable_language(C ASM)
 set(CMAKE_C_STANDARD 99)
@@ -28,7 +28,7 @@ if(CMAKE_EXPORT_COMPILE_COMMANDS)
 endif()
 
 set(ALLOWED_WARNINGS      "-Wno-type-limits")
-set(CMAKE_C_FLAGS_DEBUG   "-g -DUSE_NEON -O0 -DDEBUG -march=native -flax-vector-conversions")
+set(CMAKE_C_FLAGS_DEBUG   "-g -DUSE_NEON -O0 -DDEBUG -Wall -Wextra -Wpedantic -fpermissive -march=native -flax-vector-conversions")
 set(CMAKE_C_FLAGS_RELEASE "-DUSE_NEON -O3 -DNDEBUG -Wall -Wextra -Wpedantic -fpermissive -march=native -flax-vector-conversions -ftree-vectorize -funroll-loops ${ALLOWED_WARNINGS}")
 
 set(SOURCES
diff --git a/Optimized_Implementation/neon/include/fq_arith.h b/Optimized_Implementation/neon/include/fq_arith.h
index 5dff830..cc47b99 100644
--- a/Optimized_Implementation/neon/include/fq_arith.h
+++ b/Optimized_Implementation/neon/include/fq_arith.h
@@ -30,6 +30,7 @@
 
 #include "parameters.h"
 #include "rng.h"
+#include "utils.h"
 
 // number of needed to represent q = 7
 #define NUM_BITS_Q (BITS_TO_REPRESENT(Q))
@@ -137,10 +138,25 @@ static const uint8_t fq_inv_table[128] __attribute__((aligned(64))) = {
 /// \param x[in]: input value < 127
 /// \return x^{-1} mod 127
 static inline
-FQ_ELEM fq_inv(FQ_ELEM x) {
+FQ_ELEM fq_inv_non_ct(FQ_ELEM x) {
    return fq_inv_table[x];
 } /* end fq_inv */
 
+/// NOTE: constant time
+/// NOTE: input must be reduced.
+/// \param x[in]: input value < 127
+/// \return x^{-1} mod 127
+static inline
+FQ_ELEM fq_inv(const FQ_ELEM x) {
+	FQ_ELEM ret = 0;
+	for (uint64_t i = 0; i < 127; i++) {
+		const FQ_ELEM mask = COMPUTE_CT_MASK(i, x);
+		const FQ_ELEM val = fq_inv_table[i] & mask;
+		ret ^= val;
+	}
+	return ret;
+}
+
 /// Sampling functions from the global TRNG state
 DEF_RAND(fq_star_rnd_elements, FQ_ELEM, 1, Q-1)
 DEF_RAND(rand_range_q_elements, FQ_ELEM, 0, Q-1)
diff --git a/Optimized_Implementation/neon/lib/codes.c b/Optimized_Implementation/neon/lib/codes.c
index 81a93ab..924a9dd 100644
--- a/Optimized_Implementation/neon/lib/codes.c
+++ b/Optimized_Implementation/neon/lib/codes.c
@@ -55,11 +55,11 @@ void swap_rows(FQ_ELEM r[N_pad],
 ///     else is 0
 void generator_get_pivot_flags(const rref_generator_mat_t *const G,
                                uint8_t pivot_flag [N]) {
-    for (int i = 0; i < N; i = i + 1) {
+    for (uint32_t i = 0; i < N; i = i + 1) {
         pivot_flag[i] = 1;
     }
 
-    for (int i = 0; i < K; i = i + 1) {
+    for (uint32_t i = 0; i < K; i = i + 1) {
         pivot_flag[G->column_pos[i]] = 0;
     }
 } /* end generator_get_pivot_flags */
@@ -97,7 +97,6 @@ void generator_monomial_mul(generator_mat_t *res,
 ///         1 on success
 int generator_RREF(generator_mat_t *G,
                    uint8_t is_pivot_column[N_pad]) {
-    int i, j, pivc;
     uint8_t tmp, sc;
 
     vec256_t *gm[K] __attribute__((aligned(32)));
@@ -106,14 +105,14 @@ int generator_RREF(generator_mat_t *G,
     vec256_t x, t, *rp, *rg;
 	const uint8x16_t c7f = vdupq_n_u8(0x7F);
 
-    for (i = 0; i < K; i++) {
+    for (uint32_t i = 0; i < K; i++) {
         gm[i] = (vec256_t *) G->values[i];
     }
 
-    for (i = 0; i < K; i++) {
-        j = i;
+    for (uint32_t i = 0; i < K; i++) {
+        uint32_t j = i;
         /*start by searching the pivot in the col = row*/
-        pivc = i;
+        uint32_t pivc = i;
 
         while (pivc < N) {
             while (j < K) {
@@ -207,7 +206,6 @@ int generator_RREF_pivot_reuse(generator_mat_t *G,
                                uint8_t was_pivot_column[N],
                                const int pvt_reuse_limit) {
     const uint8x16_t q = vdupq_n_u8(127);
-    int i, j, pivc;
     uint8_t sc;
     int pvt_reuse_cnt = 0;
 
@@ -227,10 +225,10 @@ int generator_RREF_pivot_reuse(generator_mat_t *G,
         }
     }
 
-    for (i = 0; i < K; i++) {
-        j = i;
+    for (uint32_t i = 0; i < K; i++) {
+        uint32_t j = i;
         /*start by searching the pivot in the col = row*/
-        pivc = i;
+        uint32_t pivc = i;
 
         while (pivc < N) {
             while (j < K) {
@@ -409,8 +407,8 @@ void compress_rref(uint8_t *compressed, const generator_mat_t *const full,
                 }
             }
         }
-    } /* end compress_rref */
-}
+    }
+}/* end compress_rref */
 
 /// Expands a compressed RREF generator matrix into a full one
 /// \param full[out]: output full matrix (K \times N)
@@ -421,11 +419,11 @@ void expand_to_rref(generator_mat_t *full,
                     const uint8_t *compressed,
                     uint8_t is_pivot_column[N]) {
     // Decompress pivot flags
-    for (int i = 0; i < N; i++) {
+    for (uint32_t i = 0; i < N; i++) {
         is_pivot_column[i] = 0;
     }
 
-    for (int col_byte = 0; col_byte < N / 8; col_byte++) {
+    for (uint32_t col_byte = 0; col_byte < N / 8; col_byte++) {
         is_pivot_column[col_byte * 8 + 0] = compressed[col_byte] & 0x1;
         is_pivot_column[col_byte * 8 + 1] = (compressed[col_byte] >> 1) & 0x1;
         is_pivot_column[col_byte * 8 + 2] = (compressed[col_byte] >> 2) & 0x1;
@@ -652,3 +650,32 @@ void normalized_monomial_right(normalized_IS_t *res,
         }
     }
 } /* end normalized_monomial_right */
+
+/// \param A[out]: pointer to allocated normalized struct, which get filled with the
+///     non-IS of the generator matrix G
+/// \param G[in]: generator matrix to extract the non-IS from.
+/// \param is_pivot_column[in]: array identifying a pivot column via a 1
+void normalized_copy_from_generator_non_information_set(normalized_IS_t *A ,
+                                                        const generator_mat_t *const G,
+                                                        const uint8_t *const is_pivot_column) {
+    // we simply copy the last N-K columns even if they are not the information set.
+    for (uint64_t i = 0; i < K; i++) {
+        memcpy((uint8_t *)A->values[i], ((uint8_t *)G->values[i]) + K, K);
+    }
+
+    // now we scan if we need to fix the non information set
+    uint32_t ctr = 0;
+    for (; ctr < K && is_pivot_column[ctr] == 1; ctr++) {}
+
+    // easy part: the last N-K columns are the non IS
+    if (ctr == K) { return; }
+
+    // "hard" part: copy all remaining columns < K into the non information set part
+    for(uint32_t j = 0; j < N-K && is_pivot_column[ctr] == 0; j++) {
+        /// copy column
+        for (uint32_t k = 0; k < K; k++) {
+            A->values[k][j] = G->values[k][ctr];
+        }
+        ctr += 1;
+    }
+}
diff --git a/Reference_Implementation/lib/monomial.c b/Reference_Implementation/lib/monomial.c
index 20c7446..fa26ea2 100644
--- a/Reference_Implementation/lib/monomial.c
+++ b/Reference_Implementation/lib/monomial.c
@@ -106,7 +106,7 @@ void monomial_sample_salt(monomial_t *res,
                           const uint16_t round_index) {
     SHAKE_STATE_STRUCT shake_monomial_state = {0};
     const int shake_buffer_len = SEED_LENGTH_BYTES + HASH_DIGEST_LENGTH + sizeof(uint16_t);
-    uint8_t shake_input_buffer[shake_buffer_len];
+    uint8_t shake_input_buffer[SEED_LENGTH_BYTES + HASH_DIGEST_LENGTH + sizeof(uint16_t)];
     memcpy(shake_input_buffer, seed, SEED_LENGTH_BYTES);
     memcpy(shake_input_buffer + SEED_LENGTH_BYTES, salt, HASH_DIGEST_LENGTH);
     memcpy(shake_input_buffer + SEED_LENGTH_BYTES + HASH_DIGEST_LENGTH, &round_index, sizeof(uint16_t));
diff --git a/Reference_Implementation/lib/seedtree.c b/Reference_Implementation/lib/seedtree.c
index e4483fd..97399f2 100644
--- a/Reference_Implementation/lib/seedtree.c
+++ b/Reference_Implementation/lib/seedtree.c
@@ -60,9 +60,8 @@ void BuildGGM(unsigned char seed_tree[NUM_NODES_SEED_TREE * SEED_LENGTH_BYTES],
               const unsigned char salt[HASH_DIGEST_LENGTH]) {
     /* input buffer to the CSPRNG, contains the seed to be expanded, a salt,
      * and the integer index of the node being expanded for domain separation */
-    const uint32_t csprng_input_len = SALT_LENGTH_BYTES +
-        SEED_LENGTH_BYTES;
-    unsigned char csprng_input[csprng_input_len];
+    const uint32_t csprng_input_len = SALT_LENGTH_BYTES + SEED_LENGTH_BYTES;
+    unsigned char csprng_input[SALT_LENGTH_BYTES + SEED_LENGTH_BYTES];
     SHAKE_STATE_STRUCT tree_csprng_state;
     memcpy(csprng_input+SEED_LENGTH_BYTES, salt, SALT_LENGTH_BYTES);
 
@@ -236,9 +235,8 @@ uint32_t RebuildGGM(unsigned char seed_tree[NUM_NODES_SEED_TREE*SEED_LENGTH_BYTE
     unsigned char flags_tree_to_publish[NUM_NODES_SEED_TREE] = {0};
     compute_seeds_to_publish(flags_tree_to_publish, indices_to_publish);
 
-    const uint32_t csprng_input_len = SALT_LENGTH_BYTES +
-        SEED_LENGTH_BYTES;
-    unsigned char csprng_input[csprng_input_len];
+    const uint32_t csprng_input_len = SALT_LENGTH_BYTES + SEED_LENGTH_BYTES;
+    unsigned char csprng_input[SALT_LENGTH_BYTES + SEED_LENGTH_BYTES];
     SHAKE_STATE_STRUCT tree_csprng_state;
 
     const uint16_t off[LOG2(T)+1] = TREE_OFFSETS;
diff --git a/Reference_Implementation/lib/transpose.c b/Reference_Implementation/lib/transpose.c
index bb05e1b..f7be8ca 100644
--- a/Reference_Implementation/lib/transpose.c
+++ b/Reference_Implementation/lib/transpose.c
@@ -256,4 +256,4 @@ void matrix_transpose_stride(uint8_t *dst,
         }
     }
 #endif
-}
\ No newline at end of file
+}