Changeset 771

Timestamp:

12/13/06 17:09:13 (2 years ago)

Author:

mfenniak

Message:

adjust pdf decryption to work on internal objects including strings. it does not appear to decrypt strings as one would expect, but I'm not sure why.

Files:

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

pypdf/trunk/pyPdf/pdf.py

@@ -215 +215 @@
-        self.read(stream)
-        self.stream = stream
+        self._override_encryption = False
-
-    ##
@@ -346 +347 @@
-        retval = readObject(self.stream, self)
-
-if retval is a stream or string, it might be encrypted:
-isinstance(retval, StringObject) or isinstance(retval, StreamObject)
+override encryption is used for the /Encrypt dictionary
+not self._override_encryption
-            # if we don't have the encryption key:
-            if self.isEncrypted and not hasattr(self, '_decryption_key'):
@@ -359 +360 @@
-            md5_hash = md5.new(key).digest()
-            key = md5_hash[:min(16, len(self._decryption_key) + 5)]
-
-
-
-
+
+
-
-        self.cacheIndirectObject(generation, idnum, retval)
-        return retval
+
+    def _decryptObject(self, obj, key):
+        if isinstance(obj, StringObject):
+            #print len(obj), obj.encode("hex_codec")
+            obj = StringObject(utils.RC4_encrypt(key, obj))
+            #print len(obj), repr(obj)
+        elif isinstance(obj, StreamObject):
+            obj._data = utils.RC4_encrypt(key, obj._data)
+        elif isinstance(obj, DictionaryObject):
+            for key, value in obj.items():
+                #if key == '/Author' or key == '/Producer':
+                #    print repr(key), repr(value), repr(utils.RC4_encrypt(key, value))
+                obj[key] = self._decryptObject(value, key)
+        elif isinstance(obj, ArrayObject):
+            for i in range(len(obj)):
+                obj[i] = self._decryptObject(obj[i], key)
+        return obj
-
-    def readObjectHeader(self, stream):
@@ -618 +634 @@
-    # method.
-    def decrypt(self, password):
+        self._override_encryption = True
+        try:
+            return self._decrypt(password)
+        finally:
+            self._override_encryption = False
+
+    def _decrypt(self, password):
-        encrypt = self.safeGetObject(self.trailer['/Encrypt'])
-        if encrypt['/Filter'] != '/Standard':