diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c
index 962674e..87b6a09 100644
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -71,13 +71,15 @@
 
 void ngx_md5_text(char *text, u_char *md5)
 {
-    /* STUB */
+    int          i;
+    static char  hex[] = "0123456789abcdef";
 
-    ngx_snprintf(text, 33,
-            "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
-            md5[0], md5[1], md5[2], md5[3], md5[4], md5[5],
-            md5[6], md5[7], md5[8], md5[9], md5[10], md5[11],
-            md5[12], md5[13], md5[14], md5[15]);
+    for (i = 0; i < 16; i++) {
+        *text++ = hex[md5[i] >> 4];
+        *text++ = hex[md5[i] & 0xf];
+    }
+
+    *text = '\0';
 }