def decrypt(in_filename, out_filename, cipher_key_getter):
key = cipher_key_getter()
if key is None:
log.error("No key to decrypt file '%s', will ignore it", in_filename)
log.debug("Decrypting file '%s' with key '%s'. Resulting file will be called '%s'." %
(in_filename, key, out_filename))
Cipher.decrypt_file(key=key, in_filename=in_filename, out_filename=out_filename)
log.info("File '%s' decrypted to '%s'." % (in_filename, out_filename))
