--- a/buffer.h	Wed Jun 03 22:59:59 2015 +0800
+++ b/buffer.h	Thu Jun 04 23:08:50 2015 +0800
@@ -56,11 +56,11 @@
 void buf_putbyte(buffer* buf, unsigned char val);
 unsigned char* buf_getptr(buffer* buf, unsigned int len);
 unsigned char* buf_getwriteptr(buffer* buf, unsigned int len);
-unsigned char* buf_getstring(buffer* buf, unsigned int *retlen);
+char* buf_getstring(buffer* buf, unsigned int *retlen);
 buffer * buf_getstringbuf(buffer *buf);
 void buf_eatstring(buffer *buf);
 void buf_putint(buffer* buf, unsigned int val);
-void buf_putstring(buffer* buf, const unsigned char* str, unsigned int len);
+void buf_putstring(buffer* buf, const char* str, unsigned int len);
 void buf_putbufstring(buffer *buf, const buffer* buf_str);
 void buf_putbytes(buffer *buf, const unsigned char *bytes, unsigned int len);
 void buf_putmpint(buffer* buf, mp_int * mp);