This example project demonstrate the use of symmetric key encryption and decryption services. The following PolarFire (SoC) User Crypto service functions are used:
- CALSymEncrypt()
- CALSymEncryptDMA()
- CALSymDecrypt()
- CALSymDecryptDMA()
On connecting PolarFire SoC Video kit J12 to the host PC, you should see 4 COM port interfaces connected. To use this project configure the COM port interface1 as below:
- 115200 baud
- 8 data bits
- 1 stop bit
- no parity
- no flow control
The example project will display instructions over the serial port. A greeting message and menu instructions are displayed over the UART. Follow the instruction to use different menu options provided by the example project and input data when requested. This program also displays the return data from User Crypto processor for encryption and decryption services.
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Data Encryption Select option '1' for data encryption using AES-256 algorithm based on electronic code book encryption (ECB) mode and key. This example project reads the plain text and an encryption key from URAT terminal and calls CALSymEncrypt() or CALSymEncryptDMA() function. The CALSymEncrypt() and CALSymEncryptDMA() functions encrypt the message based on electronic code book encryption (ECB) mode and symmetric encryption key and generates the cipher text. This cipher text is also displayed on UART terminal.
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Data Decryption Select option '2' for data decryption using AES-256 algorithm, based on electronic code book (ECB) mode and key. This example project reads a cipher text and a decryption key from URAT terminal and calls CALSymDecrypt() or CALSymDecrypt() function. The CALSymDecrypt() and CALSymDecryptDMA() functions decrypt the cipher text based on ECB mode and symmetric encryption key, and generate the plain text. The generated plain text is also displayed on UART terminal. You have to provide same key to decrypt the cipher text, which is used for encryption.
NOTE: If you try to enter data values other than 0 - 9, a - f, A - F, an error message will be displayed on the serial port terminal.
This example project is targeted at PolarFire SoC Video kit (MPFS250TS-1FCG1152I). The reference design for the PolarFire SoC video kit is available in the following GitHub repository: PolarFire® SoC Video Kit Reference Design.
The steps mentioned here can be used to generate a FlashPro Express job file from above mentioned tcl script.
This project provides build configurations and debug launchers as explained here
- PolarFire User Crypto Driver Configuration
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config_user.h is a custom configuration file for PolarFire SoC CAL library. Following are the recommended configuration for config_user.h file.
- Define g_user_crypto_base_address global variable as shown below. This will used to configure the PKX0_BASE (defined in config_user.h) and to connect to the User Crypto Co-processor in the Libero design.
uint32_t g_user_crypto_base_addr 0x22000000UL;
- SAT_LITTLE_ENDIAN - Endianness of the processor executing CAL Library customization definitions. These definitions enable the respective cryptographic services in the CAL which are supported by the User Crypto Processor. It is recommended that these definitions are not removed or changed unless required.
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A symbol INC_STDINT_H is defined in project preprocessor setting. For more detail, please refer to caltypes.h file present in CAL folder.
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NOTE: You must enter all input data as whole bytes. If you enter the 128-bit key {1230...0} as 0x12 0x3 and press return, this will be treated as byte0 =0x12, byte1 = 0x30, byte2-127 = 0x00.
A macro script is provided with this example which automatically enters the NIST vectors and associated data to verify the functionality. You can use AES_Cryptography.ttl Tera Term Macro script present in project directory for testing AES Cryptography example project.
NOTE:
- Tera Term Macros don’t work with Windows 10 build 14393.0. You should update to Windows 10 build 14393.0.105 or later.
- Before running Tera Term Macro script, set language as English (Setup->General->Language). Also setup transmit delay in (Setup->Serial port) to 5msec/char and 5msec/line.
- By default, Tera Term log will be stored in Tera Term installation Directory.
This example is tested on PolarFire SoC Video kit (MPFS250TS-1FCG1152I).
The CAL source code is bound by license agreement. If you need access to the CAL source code, please contact FPGA_marketing@microchip.com for further details on NDA requirements.