diff --git a/internal/v4a/shared_test.go b/internal/v4a/shared_test.go
index 4f36aca8684..6c944008a32 100644
--- a/internal/v4a/shared_test.go
+++ b/internal/v4a/shared_test.go
@@ -7,7 +7,7 @@ import (
 )
 
 var stubCredentials = stubCredentialsProviderFunc(func(ctx context.Context) (Credentials, error) {
-	stubKey, err := ecdsa.GenerateKey(p256, bytes.NewReader(make([]byte, 40)))
+	stubKey, err := ecdsa.GenerateKey(p256, bytes.NewReader(bytes.Repeat([]byte{1}, 40)))
 	if err != nil {
 		return Credentials{}, err
 	}