CRYP internal peripheral

1 Article purpose[edit]

The purpose of this article is to:

  • briefly introduce the CRYP peripheral and its main features
  • indicate the level of security supported by this hardware block
  • explain how each instance can be allocated to the three runtime contexts and linked to the corresponding software components
  • explain how to configure the CRYP peripheral.

2 Peripheral overview[edit]

The CRYP peripheral provides hardware acceleration to encrypt or decrypt data using the DES[1], TDES[2] or AES[3] algorithms. It also supports multiple key sizes and chaining modes.

2.1 Features[edit]

Refer to STM32MP15 reference manuals for the complete list of features, and to the software components, introduced below, to know which features are really implemented.

2.2 Security support[edit]

CRYP1 is a secure peripheral (under ETZPC control).
CRYP2 is a non secure peripheral.

3 Peripheral usage and associated software[edit]

3.1 Boot time[edit]

CRYP1 is not used during boot process.

3.2 Runtime[edit]

CRYP1 instance can be allocated to:

or


CRYP2 instance can be allocated to:

Chapter Peripheral assignment describes which peripheral instance can be assigned to which context.

3.2.1 Software frameworks[edit]

Domain Peripheral Software frameworks Comment
Cortex-A7
secure
(OP-TEE)
Cortex-A7
non-secure
(Linux)
Cortex-M4

(STM32Cube)
Security CRYP CRYP OP-TEE driver Linux Crypto framework STM32Cube CRYP driver

3.2.2 Peripheral configuration[edit]

The configuration is applied by the firmware running in the context to which the peripheral is assigned. The configuration can be done alone via the STM32CubeMX tool for all internal peripherals, and then manually completed (particularly for external peripherals), according to the information given in the corresponding software framework article.

3.2.3 Peripheral assignment[edit]

Internal peripherals

Check boxes illustrate the possible peripheral allocations supported by STM32 MPU Embedded Software:

  • means that the peripheral can be assigned () to the given runtime context.
  • is used for system peripherals that cannot be unchecked because they are statically connected in the device.

Refer to How to assign an internal peripheral to a runtime context for more information on how to assign peripherals manually or via STM32CubeMX.
The present chapter describes STMicroelectronics recommendations or choice of implementation. Additional possiblities might be described in STM32MP15 reference manuals.

Domain Peripheral Runtime allocation Comment
Instance Cortex-A7
secure
(OP-TEE)
Cortex-A7
non-secure
(Linux)
Cortex-M4

(STM32Cube)
Security CRYP CRYP1 Assignment (single choice)
CRYP2

4 How to go further[edit]

Not applicable.

5 References[edit]




Cryptographic processor

Data Encryption Standard

Triple Data Encryption Standard

Advanced Encryption Standard

Open Portable Trusted Execution Environment

Microprocessor Unit

Attachments

Discussions