diff --git a/src/libstrongswan/chunk.c b/src/libstrongswan/chunk.c
index c9c181f87..40a93e21a 100644
--- a/src/libstrongswan/chunk.c
+++ b/src/libstrongswan/chunk.c
@@ -19,6 +19,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <errno.h>
+#include <ctype.h>
 
 #include "chunk.h"
 
@@ -441,6 +442,32 @@ int chunk_compare(chunk_t a, chunk_t b)
 	return memcmp(a.ptr, b.ptr, len);
 };
 
+/**
+ * Remove non-printable characters from a chunk.
+ */
+bool chunk_printable(chunk_t chunk, chunk_t *sane, char replace)
+{
+	bool printable = TRUE;
+	int i;
+	
+	if (sane)
+	{
+		*sane = chunk_clone(chunk);
+	}
+	for (i = 0; i < chunk.len; i++)
+	{
+		if (!isprint(chunk.ptr[i]))
+		{
+			if (sane)
+			{
+				sane->ptr[i] = replace;
+			}
+			printable = FALSE;
+		}
+	}
+	return printable;
+}
+
 /**
  * Described in header.
  * 
diff --git a/src/libstrongswan/chunk.h b/src/libstrongswan/chunk.h
index 3d8c360c5..bc5c3574a 100644
--- a/src/libstrongswan/chunk.h
+++ b/src/libstrongswan/chunk.h
@@ -231,6 +231,19 @@ static inline bool chunk_equals(chunk_t a, chunk_t b)
 			a.len == b.len && memeq(a.ptr, b.ptr, a.len);
 }
 
+/**
+ * Check if a chunk has printable characters only.
+ *
+ * If sane is given, chunk is cloned into sane and all non printable characters
+ * get replaced by "replace".
+ *
+ * @param chunk			chunk to check for printability
+ * @param sane			pointer where sane version is allocated, or NULL
+ * @param replace		character to use for replaceing unprintable characters
+ * @return				TRUE if all characters in chunk are printable
+ */
+bool chunk_printable(chunk_t chunk, chunk_t *sane, char replace);
+
 /**
  * Computes a 32 bit hash of the given chunk.
  * Note: This hash is only intended for hash tables not for cryptographic purposes.