diff --git a/include/nil/crypto3/multiprecision/cpp_modular.hpp b/include/nil/crypto3/multiprecision/cpp_modular.hpp
index bcd97a2b..99cab803 100644
--- a/include/nil/crypto3/multiprecision/cpp_modular.hpp
+++ b/include/nil/crypto3/multiprecision/cpp_modular.hpp
@@ -22,6 +22,8 @@ namespace nil {
             typedef modular_params<cpp_int_backend<>> cpp_mod_params;
 
             // Fixed precision unsigned types:
+            typedef modular_params<cpp_int_backend<64, 64, unsigned_magnitude, unchecked, void>>
+                umod_params_params64_t;
             typedef modular_params<cpp_int_backend<128, 128, unsigned_magnitude, unchecked, void>>
                 umod_params_params128_t;
             typedef modular_params<cpp_int_backend<256, 256, unsigned_magnitude, unchecked, void>> umod_params256_t;
diff --git a/include/nil/crypto3/multiprecision/modular/inverse.hpp b/include/nil/crypto3/multiprecision/modular/inverse.hpp
index a8a86aeb..2ea10b0a 100644
--- a/include/nil/crypto3/multiprecision/modular/inverse.hpp
+++ b/include/nil/crypto3/multiprecision/modular/inverse.hpp
@@ -19,6 +19,14 @@ namespace nil {
     namespace crypto3 {
         namespace multiprecision {
             namespace backends {
+
+                using default_ops::eval_is_zero;
+                using default_ops::eval_bit_test;
+                using default_ops::eval_modulus;
+                using default_ops::eval_subtract;
+                using default_ops::eval_add;
+                using default_ops::eval_bit_set;
+
                 template<typename Backend>
                 constexpr Backend eval_extended_euclidean_algorithm(Backend &num1, Backend& num2, Backend &bezout_x, Backend &bezout_y) {
                     Backend x, y, tmp_num1 = num1, tmp_num2 = num2;