Firstly, I want to describe the motivation of adding secure Flash support in TF-M.
Currently ARM TF-M provides
protected storage service(PS service for short) to implement security protection
on external normal storage, however this type external normal storage is
still vulnerable to unauthorized physical modifications/erasing and cloning.Macronix
and other Flash memory suppliers have developed secure Flash products to
enhance the security in external flash devices. Secure Flash enables mutual
authentication between itself and host MCU/SoC and only permits the authorised
host to perform access, besides, the communication channel between host
MCU/SoC and secure Flash is protected by encryption, authentication, data
scrambling, and frame sequencing with monotonic counters as shown below,
so the secure Flash provides dependable defense against unauthorised access,
man-in-the-middle, replay, sniffing and other security threats.
If we port TF-M to a platform
which uses secure Flash as external flash,then secure Flash driver should
be added to TF-M.However,compared with nomal external flash driver,secure
Flash driver needs extra crypto functions(such as calling AES crypto functions
to encrypt/decrypt data), if the secure Flash driver is placed in platform
folder in TF-M code structure as a backend of ITS service, I don't know
whether secure Flash driver is allowed to call Crypto service(such as psa_aead_encrypt(),
psa_aead_decrypt() )directly.If not, are there any other solutions to perform
crypto operations in secure Flash driver? CONFIDENTIALITY NOTE: This e-mail and any attachments may contain confidential information and/or personal data, which is protected by applicable laws. Please be reminded that duplication, disclosure, distribution, or use of this e-mail (and/or its attachments) or any part thereof is prohibited. If you receive this e-mail in error, please notify us immediately and delete this mail as well as its attachment(s) from your system. In addition, please be informed that collection, processing, and/or use of personal data is prohibited unless expressly permitted by personal data protection laws. Thank you for your attention and cooperation. Macronix International Co., Ltd. =====================================================================
Best Regards,
Poppy Wu
Macronix Microelectronics (Suzhou) Co.,Ltd
Tel: 86-512-62580888 EXT: 3147
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