diff --git a/dudect/constant.c b/dudect/constant.c
index ed252412d..ef3dceb7a 100644
--- a/dudect/constant.c
+++ b/dudect/constant.c
@@ -50,7 +50,7 @@ void prepare_inputs(uint8_t *input_data, uint8_t *classes)
 {
     randombytes(input_data, N_MEASURES * CHUNK_SIZE);
     for (size_t i = 0; i < N_MEASURES; i++) {
-        classes[i] = rand() & 1;
+        classes[i] = randombit();
         if (classes[i] == 0)
             memset(input_data + i * CHUNK_SIZE, 0, CHUNK_SIZE);
     }
diff --git a/dudect/fixture.c b/dudect/fixture.c
index fb60681a8..3c81e8347 100644
--- a/dudect/fixture.c
+++ b/dudect/fixture.c
@@ -155,7 +155,7 @@ int64_t before_ticks[N_MEASURES];
 int64_t after_ticks[N_MEASURES];
 int64_t exec_times[N_MEASURES];
 uint8_t classes[N_MEASURES];
-uint8_t input_data[N_MEASURES];
+uint8_t input_data[N_MEASURES * CHUNK_SIZE];
 FILE *dudect_out;
 static report_state_t dudect_main(int mode)
 {