diff --git a/crypto/blake2b/blake2b_ref.go b/crypto/blake2b/blake2b_ref.go
index 874c2d97a..9d0ade473 100644
--- a/crypto/blake2b/blake2b_ref.go
+++ b/crypto/blake2b/blake2b_ref.go
@@ -6,6 +6,6 @@
 
 package blake2b
 
-func f(h *[8]uint64, m [16]uint64, c0, c1 uint64, flag uint64, rounds int) {
+func f(h *[8]uint64, m *[16]uint64, c0, c1 uint64, flag uint64, rounds uint64) {
 	fGeneric(h, m, c0, c1, flag, rounds)
 }