diff --git a/tcutils/pbocfunc.py b/tcutils/pbocfunc.py
index f21bf37..c6f6b86 100644
--- a/tcutils/pbocfunc.py
+++ b/tcutils/pbocfunc.py
@@ -126,6 +126,15 @@
     k = codecs.decode(key, 'hex')
     k1 = CalcMacDES(d, id, k)
     return codecs.encode(k1, 'hex')
-    
 
-        
+
+def encrypt_m1key(inputkey):
+    statickey = codecs.decode('3230303530313331', 'hex')
+    key = codecs.decode(inputkey[:16], 'hex')
+    outkey = []
+    for i in range(8):
+        t1 = ord(key[i])
+        t2 = ord(statickey[i])
+        t = ((~t1) ^ t2) & 0xFF
+        outkey.append(chr(t))
+    return codecs.encode(''.join(outkey), 'hex')