diff --git a/tinycrypt/ecc_dsa.c b/tinycrypt/ecc_dsa.c
index b3a08cf..04b1bfa 100644
--- a/tinycrypt/ecc_dsa.c
+++ b/tinycrypt/ecc_dsa.c
@@ -220,6 +220,9 @@
 	wordcount_t num_words = curve->num_words;
 	wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
 
+	if (curve != uECC_secp256r1())
+		return 0;
+
 	rx[num_n_words - 1] = 0;
 	r[num_n_words - 1] = 0;
 	s[num_n_words - 1] = 0;