diff --git a/sha3/hashes.go b/sha3/hashes.go
index 6a383c9..2b51cf4 100644
--- a/sha3/hashes.go
+++ b/sha3/hashes.go
@@ -9,17 +9,9 @@ package sha3
 // bytes.
 
 import (
-	"crypto"
 	"hash"
 )
 
-func init() {
-	crypto.RegisterHash(crypto.SHA3_224, New224)
-	crypto.RegisterHash(crypto.SHA3_256, New256)
-	crypto.RegisterHash(crypto.SHA3_384, New384)
-	crypto.RegisterHash(crypto.SHA3_512, New512)
-}
-
 // New224 creates a new SHA3-224 hash.
 // Its generic security strength is 224 bits against preimage attacks,
 // and 112 bits against collision attacks.
diff --git a/sha3/register.go b/sha3/register.go
new file mode 100644
index 0000000..3cf6a22
--- /dev/null
+++ b/sha3/register.go
@@ -0,0 +1,18 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.4
+
+package sha3
+
+import (
+	"crypto"
+)
+
+func init() {
+	crypto.RegisterHash(crypto.SHA3_224, New224)
+	crypto.RegisterHash(crypto.SHA3_256, New256)
+	crypto.RegisterHash(crypto.SHA3_384, New384)
+	crypto.RegisterHash(crypto.SHA3_512, New512)
+}