Help¶

AES lookup tables will be placed in ROM instead of RAM Placing the AES lookup tables in ROM will perform slower but will reduce RAM usage. Using precompiled ROM tables reduces RAM size by ~8kB with an additional cost of ~8kB of ROM size. If MBEDTLS_AES_FEWER_TABLES is used the RAM reduction is ~2kB with an additional cost of ~2kB of ROM size. MBEDTLS_AES_ROM_TABLES setting in mbed TLS config file.

Direct dependencies¶

(VANILLA_MBEDTLS_AES_C && NRF_SECURITY_ADVANCED && NRF_SECURITY_ANY_BACKEND && NORDIC_SECURITY_BACKEND) || (MBEDTLS_CIPHER_AES_ENABLED && MBEDTLS_BUILTIN && MBEDTLS_CFG_FILE = “config-tls-generic.h” && MBEDTLS)

(Includes any dependencies from ifs and menus.)

Default¶

y

Kconfig definitions¶

At <nrfxlib>/nrf_security/Kconfig:1425

Included via <Zephyr>/Kconfig:8 → <Zephyr>/Kconfig.zephyr:9 → <BuildDir>/Kconfig/Kconfig.modules:5 → <nrfxlib>/Kconfig.nrfxlib:13

Menu path: (Top) → Modules → Nordic nrfxlib → Nordic Security → Use Nordic provided security backend → Advanced mbed TLS Configuration Settings

config MBEDTLS_AES_ROM_TABLES
    bool "Use AES ROM tables"
    depends on VANILLA_MBEDTLS_AES_C && NRF_SECURITY_ADVANCED && NRF_SECURITY_ANY_BACKEND && NORDIC_SECURITY_BACKEND
    help
      AES lookup tables will be placed in ROM instead of RAM
      Placing the AES lookup tables in ROM will perform slower but will reduce RAM usage.
      Using precompiled ROM tables reduces RAM size by ~8kB with an additional
      cost of ~8kB of ROM size.
      If MBEDTLS_AES_FEWER_TABLES is used the RAM reduction is ~2kB with an
      additional cost of ~2kB of ROM size.
      MBEDTLS_AES_ROM_TABLES setting in mbed TLS config file.

At <Zephyr>/modules/Kconfig.tls-generic:193

Included via <Zephyr>/Kconfig:8 → <Zephyr>/Kconfig.zephyr:10 → <Zephyr>/modules/Kconfig:17 → <Zephyr>/modules/Kconfig.mbedtls:44

Menu path: (Top) → Modules → mbedTLS Support → TLS configuration → Ciphersuite configuration → Enable the AES block cipher

config MBEDTLS_AES_ROM_TABLES
    bool "Use precomputed AES tables stored in ROM."
    default y
    depends on MBEDTLS_CIPHER_AES_ENABLED && MBEDTLS_BUILTIN && MBEDTLS_CFG_FILE = "config-tls-generic.h" && MBEDTLS

(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)