LPC55S69 : Casper and ECC521 support

[EugeneHiihtaja]

Hello !

I have taken latest SDK and IDE for LPC55S69 MCU and try to execute mbedtls benchmark test.

It seems to me ECC521 cryptography doesn't supported by CASPER accelerator at all.

I have expected if it will be partially accelerated on HW in way how it is done on K82 and LTC.

ecp_alt_ksdk.c have protections like this :

#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \
defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
#error "CASPER hw acceleration currently supported only for SECP256R1 and SECP384R1."
#endif

..

#if (ECC_SIZE_BITS == 256)
CASPER_ECC_SECP256R1_Mul(CASPER, &p.data.w[1], &p.data.w[1 + (ECC_SIZE_BYTES / sizeof(uint32_t))],
&p.data.w[1], &p.data.w[1 + (ECC_SIZE_BYTES / sizeof(uint32_t))], (void *)M);
#elif (ECC_SIZE_BITS == 384)
CASPER_ECC_SECP384R1_Mul(CASPER, &p.data.w[1], &p.data.w[1 + (ECC_SIZE_BYTES / sizeof(uint32_t))],
&p.data.w[1], &p.data.w[1 + (ECC_SIZE_BYTES / sizeof(uint32_t))], (void *)M);
#endif

Does it coming at some point or we can expect SW ECC521 only ?

By the way, do you have Reference manual for LPC55S69 MCU or only  Datasheet and UserGuide ?

Regards,

Eugene

[ZhangJennie]

Hi

As I know, only AWS supports 521b(EC_secp521r1). It should be enabled in aws_medtls_config.h of SDK.

if you downloaded the SDK including AWS, you can find aws_examples folder under the package.

Besides user guide and datasheet, other application notes for LPC55s69 are posted here

LPC55S6x|Arm® Cortex®-M33|32-bit Microcontrollers (MCUs) | NXP 

Have a great day,
Jun Zhang

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[EugeneHiihtaja]

Hi Jun Zhang !

I have checked aws_mbedtls_config.h file in all 4 examples and ECC521 is not used there at all.

//#define MBEDTLS_ECP_DP_SECP521R1_ENABLED

Not even in pure SW way e.h without acceleration.

Could it be possible for your to check current state of ECC521 in mdedtls for LPC55S69 ?

Usage of CASPER HW accelerator should increase ECC521 performance twice at list and we need it.

By the way, I haven't find any examples and/or application note for proper activation of L1 caches and flash prefetch caches for burst

SW performance of  LPC55S69.

Could you point me to any material about it.

Thank you !

Regards,

Eugene

[ZhangJennie]

Hi Eugene Hiihtaja,

I need check its status with SDK team, please let me know what's your project name (application scenarios). I need it to compose my request.

If you don't want to share it to public, please send me message of community.  (right click on my name, you can send). Thanks.

Have a nice day,

Jun Zhang

[EugeneHiihtaja]

Hi Jun Zhang !

My application require fast execution of the next cryptoperation what directly supported by mbedtls library.

In case of of K82 we able to use LTC for partially acceleration of all ECC521 relative cryptography and it is faster that pure SW routines.

K82 150Mhz; ECC521 pure SW

ECDSA-secp521r1 : 6.00 sign/s
ECDSA-secp521r1 : 2.00 verify/s
ECDHE-secp521r1 : 2.00 handshake/s
ECDH-secp521r1 : 3.00 handshake/s

K82 150 Mhz, ECC521 partially HW accelerated ( standart configuration from KSDK )

ECDSA-secp521r1 : 7.67 sign/s
ECDSA-secp521r1 : 2.33 verify/s
ECDHE-secp521r1 : 2.33 handshake/s
ECDH-secp521r1 : 3.33 handshake/s

and it little bit faster.

In case of LPC55S69- 150 Mhz, I can use only pure SW support for ECC521 operations

ECDSA-secp521r1 : 3.67 sign/s
ECDSA-secp521r1 : 1.33 verify/s
ECDHE-secp521r1 : 1.33 handshake/s
ECDH-secp521r1 : 1.67 handshake/s

And they is slowly than even K82 at the same MCU clock. How it is possible ?

Can CASPER HW accelerator to be used for partial acceleration of ECC521 cryptography ?

LPC should be faster than K82. Is this so ?

Regards,

Eugene

[ZhangJennie]

Hi Eugene, 

I got feedback from SDK developerment : 

CASPER HW / SDK CASPER driver doesn’t support ECC521 at this moment..

Thanks,

Jun Zhang

[EugeneHiihtaja]

Hi Zhang!

But what about feature?

Or it cant be done in principle and we will have pure SW Ecc521 forever?

Regards,

Eugene

[ZhangJennie]

Hi Eugene, 

There is no plan to have CASPER HW / SDK CASPER driver support on current road map in near future.

I will escalate it as a feature request. But for now, we don't have that.

Have a great day,
Jun Zhang

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