Changeset 768

Timestamp:

12/12/06 22:26:54 (2 years ago)

Author:

mfenniak

Message:

support for rev3+ user passwords only

Files:

• pypdf/trunk/pyPdf/pdf.py (modified) (4 diffs)

pypdf/trunk/pyPdf/pdf.py

@@ -515 +515 @@
-            '\xa9\xfe\x64\x53\x69\x7a'
-
-
+, metadata_encrypt=True
-        import md5, struct
-        m = md5.new()
@@ -529 +529 @@
-        id1_entry = self.safeGetObject(id_entry[0])
-        m.update(id1_entry)
-#if rev >= 3
-#    if document metadata is not being encrypted, pass \xff\xff\xff\xff into hash
+if rev >= 3 and not metadata_encrypt
+    m.update("\xff\xff\xff\xff")
-        md5_hash = m.digest()
-
-
-
-
-
+
+
+
-        return md5_hash[:keylen]
-
-    def _alg34(self, password):
-
-
-
-
+
-        U = utils.RC4_encrypt(key, self._encryption_padding)
-        return U
@@ -556 +551 @@
-        key = md5_hash[:5]
-        return key
+
+    def _alg35(self, password, rev, keylen, metadata_encrypt):
+        import md5
+        m = md5.new()
+        m.update(self._encryption_padding)
+        id_entry = self.safeGetObject(self.trailer['/ID'])
+        id1_entry = self.safeGetObject(id_entry[0])
+        m.update(id1_entry)
+        md5_hash = m.digest()
+        key = self._alg32(password, rev, keylen)
+        val = utils.RC4_encrypt(key, md5_hash)
+        for i in range(1, 20):
+            new_key = ''
+            for l in range(len(key)):
+                new_key += chr(ord(key[l]) ^ i)
+            val = utils.RC4_encrypt(new_key, val)
+        return val + ('\x00' * 16)
-
-    ##
@@ -577 +589 @@
-    def _authenticateUserPassword(self, password):
-        encrypt = self.safeGetObject(self.trailer['/Encrypt'])
+        rev = self.safeGetObject(encrypt['/R'])
+        if rev == 2:
+            U = self._alg34(password)
+        elif rev >= 3:
+            U = self._alg35(password, rev, self.safeGetObject(encrypt["/Length"]) / 8,
+                    self.safeGetObject(encrypt.get("/EncryptMetadata", False)))
-        real_U = self.safeGetObject(encrypt['/U'])
-        U = self._alg34(password)
-        return U == real_U
-