NRF9160-SICA-R7 datasheet(145/400 Pages) NORDIC

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Peripherals

• If attempting to push a key slot with default permissions

• EVENTS_KEYSLOT_REVOKED if a key slot is marked as revoked in its key header configuration

6.8.4.2.5 Revoking the key slots

All key slots within the key storage area can be marked as revoked.

To revoke any key slots, write to the STATE field in the KEYSLOT.CONFIG[ID-1].PERM register. The following

rules apply to keys that have been revoked:

1. Key slots that have the PUSH field enabled in PERM register can no longer be pushed. If a revoked key

slot is selected and task TASKS_PUSH_KEYSLOT is started, the event EVENTS_KEYSLOT_REVOKED is

triggered.

2. Key slots that have the READ field enabled in PERM register can no longer be read. Any read operation

to a revoked key value will return word 0xDEADDEAD.

3. Previously pushed key values stored in a peripheral write-only key register are not affected by key

revocation. If secure code wants to enforce that a revoked key is no longer usable by a peripheral for

cryptographic operations, the secure code should disable or reset the peripheral in question.

6.8.4.3 STATUS register

The KMU uses a STATUS register to indicate its status of operation. The SELECTED bit will be asserted

whenever the currently selected key slot is successfully read from or written to.

All read or write operations to other key slots than what is currently selected in KMU->SELECTKEYSLOT

will assert the BLOCKED bit. The BLOCKED bit will also be asserted if the KMU fails to select a key slot, or

if a request has been blocked due to an access violation. Normal operation using the KMU should never

trigger the BLOCKED bit. If this bit is triggered during the development phase, it indicates that the code is

using the KMU incorrectly.

The STATUS register is reset every time register SELECTKEYSLOT is written.

6.8.5 Registers

Base address Peripheral

Instance

Secure mapping

DMA security

Description

Configuration

0x50039000

0x40039000

KMU

KMU : S

KMU : NS

SPLIT

Key management unit

Table 52: Instances

Offset

Security Description

TASKS_PUSH_KEYSLOT

0x0000

Push a key slot over secure APB

EVENTS_KEYSLOT_PUSHED

0x100

Key slot successfully pushed over secure APB

EVENTS_KEYSLOT_REVOKED

0x104

Key slot has been revoked and cannot be tasked for selection

EVENTS_KEYSLOT_ERROR

0x108

No key slot selected, no destination address defined, or error during push operation

INTEN

0x300

Enable or disable interrupt

INTENSET

0x304

Enable interrupt

INTENCLR

0x308

Disable interrupt

INTPEND

0x30C

Pending interrupts

STATUS

0x40C

Status bits for KMU operation

SELECTKEYSLOT

0x500

Select key slot to be read over AHB or pushed over secure APB when TASKS_PUSH_KEYSLOT

is started

Table 53: Register overview

4418_1315 v2.0

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