diff --git a/ecdsa.c b/ecdsa.c
index e166ff8f0..1f0e836c9 100644
--- a/ecdsa.c
+++ b/ecdsa.c
@@ -879,7 +879,7 @@ void ecdsa_get_address_raw(const uint8_t *pub_key, uint32_t version, uint8_t *ad
 
 void ecdsa_get_address(const uint8_t *pub_key, uint32_t version, char *addr, int addrsize)
 {
-	uint8_t raw[20+4];
+	uint8_t raw[MAX_ADDR_RAW_SIZE];
 	ecdsa_get_address_raw(pub_key, version, raw);
 	if (version <= 0xFF) {
 		base58_encode_check(raw, 21, addr, addrsize);
@@ -896,7 +896,7 @@ void ecdsa_get_address(const uint8_t *pub_key, uint32_t version, char *addr, int
 
 void ecdsa_get_wif(const uint8_t *priv_key, uint32_t version, char *wif, int wifsize)
 {
-	uint8_t wif_raw[4 + 32 + 1];
+	uint8_t wif_raw[MAX_WIF_RAW_SIZE];
 
 	if (version <= 0xFF) {
 		wif_raw[0] = version;
diff --git a/ecdsa.h b/ecdsa.h
index a07e418ca..5b785617a 100644
--- a/ecdsa.h
+++ b/ecdsa.h
@@ -48,6 +48,9 @@ typedef struct {
 
 } ecdsa_curve;
 
+#define MAX_ADDR_RAW_SIZE (4 + 20)
+#define MAX_WIF_RAW_SIZE (4 + 32 + 1)
+
 // rfc6979 pseudo random number generator state
 typedef struct {
 	uint8_t v[32], k[32];
diff --git a/tests.c b/tests.c
index 0eda9710e..964e6e11a 100644
--- a/tests.c
+++ b/tests.c
@@ -2150,9 +2150,8 @@ END_TEST
 START_TEST(test_address_decode)
 {
 	int res;
-	uint8_t decode[21];
-	// byte      0 : address type
-	// bytes  1-20 : pubkey hash 160
+	uint8_t decode[MAX_ADDR_RAW_SIZE];
+
 	res = ecdsa_address_decode("1JwSSubhmg6iPtRjtyqhUYYH7bZg3Lfy1T", decode);
 	ck_assert_int_eq(res, 1);
 	ck_assert_mem_eq(decode, fromhex("00c4c5d791fcb4654a1ef5e03fe0ad3d9c598f9827"), 21);