diff --git a/ineptpdf.pyw b/ineptpdf.pyw
index cac8a5e..8674733 100644
--- a/ineptpdf.pyw
+++ b/ineptpdf.pyw
@@ -1,6 +1,6 @@
 #! /usr/bin/python
 
-# ineptpdf5.pyw, version 5
+# ineptpdf.pyw, version 6
 
 # To run this program install Python 2.6 from http://www.python.org/download/
 # and PyCrypto from http://www.voidspace.org.uk/python/modules.shtml#pycrypto
@@ -13,7 +13,7 @@
 #   3 - Correctly handle PDF >=1.5 cross-reference streams
 #   4 - Removal of ciando's personal ID (anon)
 #   5 - removing small bug with V3 ebooks (anon)
-
+#   6 - changed to adeptkey4.der format for 1.7.2 support (anon)
 """
 Decrypt Adobe ADEPT-encrypted PDF files.
 """
@@ -34,6 +34,7 @@ import Tkinter
 import Tkconstants
 import tkFileDialog
 import tkMessageBox
+import pickle
 
 try:
     from Crypto.Cipher import ARC4
@@ -1170,38 +1171,52 @@ class PDFDocument(object):
 
     def initialize_ebx(self, password, docid, param):
         self.is_printable = self.is_modifiable = self.is_extractable = True
-        with open(password, 'rb') as f:
-            keyder = f.read()
-        key = ASN1Parser([ord(x) for x in keyder])
-        key = [bytesToNumber(key.getChild(x).value) for x in xrange(1, 4)]
-        rsa = RSA.construct(key)
-        length = int_value(param.get('Length', 0)) / 8
-        rights = str_value(param.get('ADEPT_LICENSE')).decode('base64')
-        rights = zlib.decompress(rights, -15)
-        rights = etree.fromstring(rights)
-        expr = './/{http://ns.adobe.com/adept}encryptedKey'
-        bookkey = ''.join(rights.findtext(expr)).decode('base64')
-        bookkey = rsa.decrypt(bookkey)
-        if bookkey[0] != '\x02':
-            raise ADEPTError('error decrypting book session key')
-        index = bookkey.index('\0') + 1
-        bookkey = bookkey[index:]
-        ebx_V = int_value(param.get('V', 4))
-        ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
-        # added because of the booktype / decryption book session key error
-        if ebx_V == 3:
-            V = 3        
-        elif ebx_V < 4 or ebx_type < 6:
-            V = ord(bookkey[0])
-            bookkey = bookkey[1:]
-        else:
-            V = 2
-        if length and len(bookkey) != length:
-            raise ADEPTError('error decrypting book session key')
-        self.decrypt_key = bookkey
-        self.genkey = self.genkey_v3 if V == 3 else self.genkey_v2
-        self.decipher = self.decrypt_rc4
-        self.ready = True
+        with open(password, 'r') as f:
+            keyderlist = pickle.load(f)
+        keynotfound = 1
+        for keyder in keyderlist:
+            key = ASN1Parser([ord(x) for x in keyder])
+            key = [bytesToNumber(key.getChild(x).value) for x in xrange(1, 4)]
+            try:            
+                rsa = RSA.construct(key)
+            except Exception:
+                continue            
+            length = int_value(param.get('Length', 0)) / 8
+            rights = str_value(param.get('ADEPT_LICENSE')).decode('base64')
+            rights = zlib.decompress(rights, -15)
+            rights = etree.fromstring(rights)
+            expr = './/{http://ns.adobe.com/adept}encryptedKey'
+            bookkey = ''.join(rights.findtext(expr)).decode('base64')
+            try:    
+                bookkey = rsa.decrypt(bookkey)
+            except Exception:
+                continue                
+            if bookkey[0] != '\x02':
+                keynotfound = 1
+                continue                
+            else:
+                keynotfound = 0
+            index = bookkey.index('\0') + 1
+            bookkey = bookkey[index:]
+            ebx_V = int_value(param.get('V', 4))
+            ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
+            # added because of the booktype / decryption book session key error
+            if ebx_V == 3:
+                V = 3        
+            elif ebx_V < 4 or ebx_type < 6:
+                V = ord(bookkey[0])
+                bookkey = bookkey[1:]
+            else:
+                V = 2
+            if length and len(bookkey) != length:
+                raise ADEPTError('error decrypting book session key')
+            self.decrypt_key = bookkey
+            self.genkey = self.genkey_v3 if V == 3 else self.genkey_v2
+            self.decipher = self.decrypt_rc4
+            self.ready = True
+            break
+        if keynotfound == 1:
+            raise ADEPTError('problem decrypting session key')
         return
     
     PASSWORD_PADDING = '(\xbfN^Nu\x8aAd\x00NV\xff\xfa\x01\x08..' \
@@ -1657,8 +1672,8 @@ class DecryptionDialog(Tkinter.Frame):
         Tkinter.Label(body, text='Key file').grid(row=0)
         self.keypath = Tkinter.Entry(body, width=30)
         self.keypath.grid(row=0, column=1, sticky=sticky)
-        if os.path.exists('adeptkey.der'):
-            self.keypath.insert(0, 'adeptkey.der')
+        if os.path.exists('adeptkey4.der'):
+            self.keypath.insert(0, 'adeptkey4.der')
         button = Tkinter.Button(body, text="...", command=self.get_keypath)
         button.grid(row=0, column=2)
         Tkinter.Label(body, text='Input file').grid(row=1)