diff --git a/validate.h b/validate.h
index 6a4e6707..2da9b4fb 100644
--- a/validate.h
+++ b/validate.h
@@ -126,7 +126,7 @@ class StreamState
 {
 public:
 	StreamState(std::ostream& out)
-		: m_out(out), m_fmt(out.flags()), m_prec(out.precision())
+		: m_out(out), m_fmt(out.flags()), m_prec(out.precision()), m_fill(out.fill())
 	{
 	}
 
@@ -134,12 +134,14 @@ public:
 	{
 		m_out.precision(m_prec);
 		m_out.flags(m_fmt);
+		m_out.fill(m_fill);
 	}
 
 private:
 	std::ostream& m_out;
 	std::ios_base::fmtflags m_fmt;
 	std::streamsize m_prec;
+	char m_fill;
 };
 
 // Safer functions on Windows for C&A, https://github.com/weidai11/cryptopp/issues/55