Fix errors for unencrypted documents

msoffcrypto/format/ooxml.py

@@ -116,9 +116,7 @@ def __init__(self, file):
  elif self.type == "extensible":
  pass
  elif zipfile.is_zipfile(file):
- self.file = file
- self.type, self.info = None, None
- self.secret_key = None
+ raise exceptions.FileFormatError("Unencrypted document or unsupported file format")
  else:
  raise exceptions.FileFormatError("Unsupported file format")
 
@@ -170,6 +168,8 @@ def load_key(self, password=None, private_key=None, secret_key=None, verify_pass
  raise exceptions.DecryptionError("Unsupported key type for the encryption method")
  elif secret_key:
  self.secret_key = secret_key
+ else:
+ raise exceptions.DecryptionError("No key specified")
 
  def decrypt(self, ofile, verify_integrity=False):
  if self.type == "agile":
@@ -193,6 +193,8 @@ def decrypt(self, ofile, verify_integrity=False):
  with self.file.openstream("EncryptedPackage") as stream:
  obuf = ECMA376Standard.decrypt(self.secret_key, stream)
  ofile.write(obuf)
+ else:
+ raise exceptions.DecryptionError("Unsupported encryption method")
 
  # If the file is successfully decrypted, there must be a valid OOXML file, i.e. a valid zip file
  if not zipfile.is_zipfile(io.BytesIO(obuf)):