diff --git a/include/polarssl/sha1.h b/include/polarssl/sha1.h
index 76b369a..0d5e67e 100644
--- a/include/polarssl/sha1.h
+++ b/include/polarssl/sha1.h
@@ -29,6 +29,8 @@
 
 #include <string.h>
 
+#define POLARSSL_ERR_SHA1_FILE_IO_ERROR                -0x0076  /**< Read/write error in file. */
+
 /**
  * \brief          SHA-1 context structure
  */
@@ -86,8 +88,7 @@
  * \param path     input file name
  * \param output   SHA-1 checksum result
  *
- * \return         0 if successful, 1 if fopen failed,
- *                 or 2 if fread failed
+ * \return         0 if successful, or POLARSSL_ERR_SHA1_FILE_IO_ERROR
  */
 int sha1_file( const char *path, unsigned char output[20] );