diff --git a/Source/scalable/scalable_test_primes.ml b/Source/scalable/scalable_test_primes.ml
index 9c2f4b7..1148d47 100644
--- a/Source/scalable/scalable_test_primes.ml
+++ b/Source/scalable/scalable_test_primes.ml
@@ -5,10 +5,37 @@ open Scalable_basic_arithmetics
 open Scalable_power
 
 (** Deterministic primality test *)
-let is_prime n = true
+let is_prime n =
+  if n = [0;0;1] || n = [0;1;1] then
+    true
+  else
+    if mod_b n [0;0;1] = [] || mod_b n [0;1;1] = [] then
+      false
+    else
+      let rec is_prime_rec k =
+        let test_inf = diff_b (mult_b [0;0;1;1] k) [0;1] in
+        let test_sup = add_n test_inf [0;0;1] in
+        if (>>) (mult_b test_inf test_inf) n then
+          true
+        else
+          match (test_inf, test_sup) with
+              (a, b) when mod_b n a = [] || mod_b n b = [] -> false
+            | _ -> is_prime_rec (add_n k [0;1])
+      in is_prime_rec [0;1];;
 
 (** Pseudo-primality test based on Fermat's Little Theorem
     @param p tested bitarray
     @param testSeq sequence of bitarrays againt which to test
  *)
-let is_pseudo_prime p test_seq = true
+let is_pseudo_prime p test_seq =
+    let rec is_pseudo_prime_rec l =
+      match l with
+          [] -> true
+        | e::l1 when mod_power e (diff_b p [0;1]) p <> [0;1] -> begin
+          if gcd_b e p = [0;1] then
+            false
+          else
+            is_pseudo_prime_rec l1
+        end
+        | _::l1 -> is_pseudo_prime_rec l1
+    in is_pseudo_prime_rec test_seq;;