AN4240 Datasheet, PDF (1/30 Pages) STMicroelectronics – This application note provides an easy introduction to the usage

AN4240
Application note
Introduction to the Cryptographic Service Engine (CSE) module for
SPC56ECxx and SPC564Bxx devices
Introduction
This application note provides an easy introduction to the usage of the CSE module inside the
SPC56ECxx and SPC564Bxx family of devices.
The CSE module implements the security functions described in the Secure Hardware Extension (SHE)
functional specification version 1.1.
Three examples show main the features of the cryptographic service engine and in the same time the
differences between the Electronic Code Book (ECB), and the Cipher Block Chaining (CBC) mode of the
Advanced Encryption Standard (AES) algorithm, defined by SHE specification.
In particular, first example shows how to load cryptographic keys into secure flash in order to permit the
usage of the cryptographic module. Second application code shows that if a data or an image has a low
variance, the CBC cipher mode provides a best performance in terms of message encryption in
comparison with the ECB cipher mode. Last example code shows how to release a Secure Boot in order
to prevent application code from being altered by an unauthorized party cipher.
September 2013
Doc ID024189 Rev 2
1/30
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