Parallelizable Encryption Mode with Almost Free Message Integrity

In this document we propose a new mode of operation for symmetric key block cipher algorithms. The main feature distinguishing the proposed mode from existing modes is that along with providing con dentiality of the message, it also provides message integrity. In other words, the new mode is not just a mode of operation for encryption, but a mode of operation for authenticated encryption. As the title of the document suggests, the new mode achieves the additional property with little extra overhead, as will be explained below.