diff --git a/tinycrypt/ecc.c b/tinycrypt/ecc.c
index 1328ea2..2e99bc9 100644
--- a/tinycrypt/ecc.c
+++ b/tinycrypt/ecc.c
@@ -1610,10 +1610,13 @@
 static uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
 			 uECC_word_t *k1)
 {
+	wordcount_t num_n_words = NUM_ECC_WORDS;	
 	bitcount_t num_n_bits = NUM_ECC_BITS;
 
+
 	uECC_word_t carry = uECC_vli_add(k0, k, curve_n) ||
-				 uECC_vli_testBit(k0, num_n_bits);
+			     (num_n_bits < ((bitcount_t)num_n_words * uECC_WORD_SIZE * 8) &&
+			     uECC_vli_testBit(k0, num_n_bits));
 
 	uECC_vli_add(k1, k0, curve_n);