This example uses the PSA Crypto API to perform ECDH key agreement on the supported device.
The Elliptic Curve Diffie-Hellman (ECDH) is an anonymous key agreement protocol that allows two parties, each having an elliptic-curve private-public key pair, to establish a shared secret over an insecure channel.
In this example, two peers (client and server) each generate their Elliptic Curve Cryptography (ECC) key pair. They exchange public keys and compute a shared secret using their private ECC keys. These secrets are compared with each other to make sure they are equal.
The example redirects standard I/O to the virtual serial port (VCOM) of the kit. By default, the serial port setting is 115200 bps and 8-N-1 configuration.
Except for the Series 1 Cortex-M0+ device, the example has been instrumented with code to count the number of clock cycles spent in different operations. The results are printed on the VCOM serial port console. This feature can be disabled by defining PSA_CRYPTO_PRINT=0 (default is 1) in the IDE setting (Preprocessor->Defined symbols).
The following key storages are supported in this example:
The following elliptic curve keys are supported in this example:
PSA_ECC_FAMILY_SECP_R1 :PSA_ECC_FAMILY_MONTGOMERY :The following key agreement algorithm is supported in this example:
PSA_ALG_ECDHThe PSA_ALG_KEY_AGREEMENT(PSA_ALG_ECDH, PSA_ALG_HKDF(hash_alg)) algorithm is used in the PSA Crypto KDF example.
The following PSA Crypto APIs are used in this example:
psa_crypto_initpsa_key_attributes_initpsa_set_key_typepsa_set_key_bitspsa_set_key_usage_flagspsa_set_key_algorithmpsa_set_key_idpsa_set_key_lifetimepsa_generate_keypsa_reset_key_attributespsa_export_public_keypsa_raw_key_agreementpsa_destroy_keymbedtls_psa_crypto_freeAdapter Firmware under General Device Information in Simplicity Studio 5 Users Guide).Secure Firmware under General Device Information in Simplicity Studio 5 Users Guide).Device Console in Simplicity Studio 5, Line terminator: must be set to None).Platform() checkbox to browse the platform examples).4096) in sl_memory_config.h can be reset to the default value (2048) if the software fallback feature in Mbed TLS is disabled.CLIENT_KEY_ID and SERVER_KEY_ID values in app_process.h if these key IDs had already existed in NVM3.Optimize for debugging (-Og) on Simplicity IDE and None on IAR Embedded Workbench.