Crypto operations to generate key pair when TFM profile is set to minimal.

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Fri, 09 Jan 2026 09:39:47 GMT

Hi mackz

Yhank you for the update.

cc3xx driver is not as configurable as oberon driver but the CONFIG_TFM_PROFILE_TYPE_NOT_SET should allow tuning of some TF-M features.

Best regards,
Dejan

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Wed, 07 Jan 2026 14:36:02 GMT

CONFIG_TFM_PROFILE_TYPE_NOT_SET=y
CONFIG_TFM_CMAKE_BUILD_TYPE_MINSIZEREL=y
CONFIG_TFM_PARTITION_PLATFORM=y
CONFIG_TFM_PARTITION_CRYPTO=y
CONFIG_TFM_PARTITION_PROTECTED_STORAGE=n
CONFIG_TFM_PARTITION_INTERNAL_TRUSTED_STORAGE=y
CONFIG_TFM_PARTITION_INITIAL_ATTESTATION=n
CONFIG_TFM_SECURE_UART0=n

CONFIG_TFM_LOG_LEVEL_SILENCE=y
CONFIG_TFM_EXCEPTION_INFO_DUMP=n
CONFIG_TFM_ITS_STACK_SIZE=0x400
CONFIG_TFM_CRYPTO_PARTITION_STACK_SIZE=0x400
#CONFIG_TFM_ITS_STACK_SIZE=0x400
#CONFIG_TFM_CRYPTO_PARTITION_STACK_SIZE=0x400
CONFIG_TFM_CRYPTO_BUILTIN_KEYS=n
CONFIG_TFM_CRYPTO_CONC_OPER_NUM=4
CONFIG_TFM_CRYPTO_IOVEC_BUFFER_SIZE=2048
CONFIG_TFM_CRYPTO_ENGINE_BUF_SIZE=2048
CONFIG_ASSERT=n
CONFIG_ASSERT_VERBOSE=n



CONFIG_NRF_SECURITY=y

CONFIG_PSA_CRYPTO_DRIVER_CC3XX=y
CONFIG_PSA_CRYPTO_DRIVER_OBERON=n
# Entropy 
CONFIG_ENTROPY_GENERATOR=y
# Enable AES
CONFIG_PSA_WANT_KEY_TYPE_AES=y
CONFIG_PSA_WANT_AES_KEY_SIZE_128=y
# Enable ECB
CONFIG_PSA_WANT_ALG_ECB_NO_PADDING=y

# Disable everything else
CONFIG_PSA_WANT_ALG_CBC_MAC=n
CONFIG_PSA_WANT_KEY_TYPE_ECC_KEY_PAIR=n
CONFIG_PSA_WANT_KEY_TYPE_HMAC=n
CONFIG_PSA_WANT_KEY_TYPE_DERIVE=n
CONFIG_PSA_WANT_ALG_CBC_NO_PADDING=n
CONFIG_PSA_WANT_ALG_CTR=n
CONFIG_PSA_WANT_ALG_GCM=n
CONFIG_PSA_WANT_ALG_CCM=n
CONFIG_PSA_WANT_ALG_CFB=n
CONFIG_PSA_WANT_ALG_OFB=n
CONFIG_PSA_WANT_ALG_CMAC=n
CONFIG_PSA_WANT_ALG_HMAC=n
CONFIG_PSA_WANT_ALG_SHA_1=n
CONFIG_PSA_WANT_ALG_SHA_256=n
CONFIG_PSA_WANT_ALG_SHA_384=n
CONFIG_PSA_WANT_ALG_SHA_512=n
CONFIG_PSA_WANT_ALG_RSA_PKCS1V15_SIGN_RAW=n
CONFIG_PSA_WANT_ALG_RSA_PSS=n
CONFIG_PSA_WANT_ALG_RSA_OAEP=n
CONFIG_PSA_WANT_ALG_ECDSA=n
CONFIG_PSA_WANT_ALG_DETERMINISTIC_ECDSA=n
CONFIG_PSA_WANT_ALG_STREAM_CIPHER=n
CONFIG_PSA_WANT_KEY_TYPE_RAW_DATA=n
CONFIG_PSA_WANT_ALG_TLS12_PSK_TO_MS=n
CONFIG_PSA_WANT_KEY_TYPE_CHACHA20=n
CONFIG_PSA_WANT_ALG_CHACHA20_POLY1305=n

with these configs i am able to get it down to:

Memory region         Used Size  Region Size  %age Used
           FLASH:       64356 B      97792 B     65.81%
             RAM:       19436 B        48 KB     39.54%

It would be nice to be able to loose 356 bytes of flash memory so that I can shrink the static configuration but i have not find a way to get it lower.

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Wed, 07 Jan 2026 08:29:34 GMT

CONFIG_TFM_PROFILE_TYPE_NOT_SET=y
CONFIG_TFM_PARTITION_PLATFORM=n
CONFIG_TFM_PARTITION_CRYPTO=n
CONFIG_TFM_PARTITION_PROTECTED_STORAGE=n
CONFIG_TFM_PARTITION_INTERNAL_TRUSTED_STORAGE=n

with this configuration i get:

fatal error: tfm_ioctl_api.h: No such file or directory
   10 | #include "tfm_ioctl_api.h"

if i then set:

CONFIG_TFM_PARTITION_PLATFORM=y

i get:

/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(flash_otp_nv_counters_backend.o): in function `erase_flash_region':
/ncs/v2.6.1/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/template/flash_otp_nv_counters_backend.c:251: undefined reference to `Driver_FLASH0'
/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(flash_otp_nv_counters_backend.o): in function `copy_flash_region':
/ncs/v2.6.1/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/template/flash_otp_nv_counters_backend.c:277: undefined reference to `Driver_FLASH0'
/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(flash_otp_nv_counters_backend.o): in function `read_otp_nv_counters_flash':
/ncs/v2.6.1/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/template/flash_otp_nv_counters_backend.c:139: undefined reference to `Driver_FLASH0'
/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(flash_otp_nv_counters_backend.o): in function `copy_data_into_block':
/ncs/v2.6.1/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/template/flash_otp_nv_counters_backend.c:330: undefined reference to `Driver_FLASH0'
/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld: platform/libplatform_s.a(flash_otp_nv_counters_backend.o): in function `init_otp_nv_counters_flash':
/ncs/v2.6.1/modules/tee/tf-m/trusted-firmware-m/platform/ext/common/template/flash_otp_nv_counters_backend.c:213: undefined reference to `Driver_FLASH0'

if i also set:

CONFIG_TFM_PARTITION_INTERNAL_TRUSTED_STORAGE=y

i get:

/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: zephyr/drivers/entropy/libdrivers__entropy.a(entropy_psa_crypto.c.obj): in function `entropy_psa_crypto_rng_get_entropy':
ncs/v2.6.1/zephyr/drivers/entropy/entropy_psa_crypto.c:35: undefined reference to `psa_generate_random'
/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: zephyr/drivers/entropy/libdrivers__entropy.a(entropy_psa_crypto.c.obj): in function `entropy_psa_crypto_rng_init':
/ncs/v2.6.1/zephyr/drivers/entropy/entropy_psa_crypto.c:19: undefined reference to `psa_crypto_init'
collect2: error: ld returned 1 exit status

if i also set:

CONFIG_TFM_PARTITION_CRYPTO=y

it builds and now i get:

[194/198] Linking C executable bin/tfm_s.axf
Memory region         Used Size  Region Size  %age Used
           FLASH:       64916 B       256 KB     24.76%
             RAM:       45928 B        88 KB     50.97%
             
[336/338] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:      127852 B       704 KB     17.74%
             RAM:       39376 B     154264 B     25.53%
        IDT_LIST:          0 GB        32 KB      0.00%

Is this the smallest i can get that still lets me use psa crypto operations and trusted storage?

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

Achim Kraus — Wed, 07 Jan 2026 07:50:42 GMT

The missing information is a fine grained table, which shows, how much ram/flash is required for each functions/profiles. Without such a table it's then left to the user, to find that out. Unfortunately, as this thread shows, this comes with a larger working time and unsatisfying results. Maybe it requires even more time, to get better results, but as this thread also shows, plain software solutions aren't that bad.

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Wed, 07 Jan 2026 07:37:35 GMT

But if i use TFM_PROFILE_TYPE_MINIMAL and then set:

CONFIG_TFM_PARTITION_PROTECTED_STORAGE=y
CONFIG_TFM_PARTITION_CRYPTO=y

i get:

warning: TFM_PARTITION_PROTECTED_STORAGE (defined at /home/marcus/ncs/v2.6.1/nrf/modules/trusted-
firmware-m/Kconfig.tfm.defconfig:69, modules/trusted-firmware-m/Kconfig.tfm.partitions:8,
modules/trusted-firmware-m/Kconfig.tfm.partitions:8) was assigned the value 'y' but got the value
'n'. See http://docs.zephyrproject.org/latest/kconfig.html#CONFIG_TFM_PARTITION_PROTECTED_STORAGE
and/or look up TFM_PARTITION_PROTECTED_STORAGE in the menuconfig/guiconfig interface. The
Application Development Primer, Setting Configuration Values, and Kconfig - Tips and Best Practices
sections of the manual might be helpful too.

and this:

psa_status_t status = psa_crypto_init();
psa_set_key_usage_flags(&key_attributes, PSA_KEY_USAGE_ENCRYPT);
psa_set_key_algorithm(&key_attributes, PSA_ALG_ECB_NO_PADDING);  
psa_set_key_type(&key_attributes, PSA_KEY_TYPE_AES);
psa_set_key_bits(&key_attributes, 16 * 8); 
status = psa_import_key(&key_attributes, p_key, 16, &key_id);
    if (status != PSA_SUCCESS) {
        LOG_ERR("Failed to import key: %d", status);
        return;
    }

still returns -134

so what is it that is possible to configure?

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Wed, 07 Jan 2026 07:10:03 GMT

Hi sorry for the late response but i also went with the software AES (for now), i could not find any other way to get it to work without wasting ram memory.

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Tue, 06 Jan 2026 10:18:56 GMT

Hi,

Configurable build is full TF-M implementation, but it should be possible to enable/disable specific TF-M features and services.
"To configure the features of the TF-M secure image, you must choose which TF-M partitions and which secure services to include in the build."
There are Kconfig options which can be used for enabling/disabling specific services. You could try to disable those services which are not needed in your build.

Best regards,
Dejan

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

pauleffect — Mon, 05 Jan 2026 15:32:00 GMT

The documentation unfortunately doesn't clarify the core issue.

I haven't been able to use hardware-accelerated random number generation or hardware AES encryption because of RAM constraints. Neither of these operations should require dozens of kilobytes of RAM.

As it stands, the choices are:

TFM_PROFILE_TYPE_NOT_SET: Lose ~88 KB of RAM, get full TF-M functionality
TFM_PROFILE_TYPE_MINIMAL: Lose ~32 KB of RAM, get effectively nothing usable (no crypto operations work)

There's no middle ground - no way to get basic hardware crypto (AES, RNG) without sacrificing a third of the nRF9160's 256 KB RAM.

I ended up implementing software AES as a workaround. Not even Oberon - a custom AES implementation, because the nRF Security backend also appears to require the full TF-M RAM allocation to function.

The project works now, but I have serious doubts about getting it through compliance/certification without hardware-backed crypto.

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Mon, 05 Jan 2026 14:45:54 GMT

Hi pauleffect ,

Documentation specifies supported TF-M profiles. NCS documentation lists supported TF-M services and provides information how to configure TF-M build. More information can be found in configurable build.

Best regards,
Dejan

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

pauleffect — Sun, 21 Dec 2025 09:41:41 GMT

did you manage to find a solution?

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

pauleffect — Sun, 21 Dec 2025 09:41:29 GMT

The guy said "i feel like there is no way to get something inbetween not being able to use TFM for anything and it taking up all of the memory for the application."

Which implies you either go the full route, and that takes up 88 kilobytes of ram out of a measly 256. For minimal functionality - such as, you know, generating 16 bytes.

Is there ANY way of using hardware encryption WITHOUT sacrificing one third of the available ram?

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Tue, 08 Apr 2025 08:59:49 GMT

Hi,

Have you tried to use configurable build with Kconfig options shown below?

CONFIG_BUILD_WITH_TFM=y
CONFIG_TFM_PROFILE_TYPE_NOT_SET=y
CONFIG_TFM_PROFILE_TYPE_MINIMAL=n

Best regards,
Dejan

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Mon, 07 Apr 2025 05:46:33 GMT

#PSA PROTECTED STORAGE
CONFIG_BUILD_WITH_TFM=y
CONFIG_TFM_CMAKE_BUILD_TYPE_MINSIZEREL=y
CONFIG_TFM_PROFILE_TYPE_NOT_SET=n
CONFIG_TFM_PROFILE_TYPE_MINIMAL=y
CONFIG_TFM_SECURE_UART0=y
CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000

#CRYPTO 
CONFIG_NRF_SECURITY=y
CONFIG_MBEDTLS_PSA_CRYPTO_C=y
CONFIG_MBEDTLS_ENABLE_HEAP=y
CONFIG_MBEDTLS_HEAP_SIZE=16384
CONFIG_PSA_CRYPTO_DRIVER_CC3XX=y
CONFIG_PSA_CRYPTO_DRIVER_OBERON=n
CONFIG_PSA_WANT_AES_KEY_SIZE_128=y
CONFIG_PSA_WANT_KEY_TYPE_AES=y
CONFIG_PSA_WANT_ALG_ECB_NO_PADDING=y

This is what i have related to tfm and crypto

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Fri, 04 Apr 2025 13:40:30 GMT

Hi,

Can you show your project configuration?

Best regards,
Dejan

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

mackz — Fri, 04 Apr 2025 12:17:21 GMT

Yes i meant minimal and full. I am using minimal but i feel like there is no way to get something inbetween not being able to use TFM for anything and it taking up all of the memory for the application. So my questions stands:
Is there any other recommended way to do it or samples that i could look at?
Or is there any sample that describes a way to get a minimal working example with the profile set to NOT_SET?

RE: Crypto operations to generate key pair when TFM profile is set to minimal.

dejans — Fri, 04 Apr 2025 12:14:54 GMT

Hi,

Small and full TF-M profiles are not directly supported in NCS. Only minimal and configurable (full) profiles are mentioned in the documentation, first as supported in NCS and second as experimental. You can look at TF-M support in NCS and minimal TF-M configuration. There are also TF-M samples, cryptography samples and TF-M integration samples from Zephyr. Additionally, you can look at supported TF-M profiles and TF-M services.

Best regards,
Dejan