diff --git a/src/crypto/md4-internal.c b/src/crypto/md4-internal.c
index d9c737a29..cf408e84f 100644
--- a/src/crypto/md4-internal.c
+++ b/src/crypto/md4-internal.c
@@ -85,7 +85,7 @@ MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);
 	(cp)[1] = (value) >> 8;						\
 	(cp)[0] = (value); } while (0)
 
-static u8 PADDING[MD4_BLOCK_LENGTH] = {
+static const u8 PADDING[MD4_BLOCK_LENGTH] = {
 	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0