diff --git a/tinycrypt/ecc_dsa.c b/tinycrypt/ecc_dsa.c
index 230f689..70f9c8b 100644
--- a/tinycrypt/ecc_dsa.c
+++ b/tinycrypt/ecc_dsa.c
@@ -151,7 +151,7 @@
 		/* Generating _random uniformly at random: */
 		uECC_RNG_Function rng_function = uECC_get_rng();
 		if (!rng_function ||
-		    !rng_function((uint8_t *)_random, 2*NUM_ECC_WORDS*uECC_WORD_SIZE)) {
+		    rng_function((uint8_t *)_random, 2*NUM_ECC_WORDS*uECC_WORD_SIZE) != 2*NUM_ECC_WORDS*uECC_WORD_SIZE) {
 			return UECC_FAILURE;
 		}