Does LCP55S6x support RSA-3072 calculation ?

StanleyH — Wed, 23 Oct 2019 06:48:38 GMT

Hi Support team,

Our customer asks if we have 3072 bits RSA calculation ? Do we provide the RSA-2048(or 3072) algorithm in library format or can provide the source code ?

Thanks.

Re: Does LCP55S6x support RSA-3072 calculation ?

xiangjun_rong — Wed, 23 Oct 2019 08:33:29 GMT

Hi, Stanley,

Regarding your RSA encryption/decryption algorithms, the LPC55S6x uses CASPER engine to deal with it rather than cortex-M33 core.

we use the api function to calculate the RSA.

/*!
* @brief Performs modular exponentiation - (A^E) mod N.
*
* This function performs modular exponentiation.
*
* @param base CASPER base address
* @param signature first addend (in little endian format)
* @param pubN modulus (in little endian format)
* @param wordLen Size of pubN in bytes
* @param pubE exponent
* @param[out] plaintext Output array to store result of operation (in little endian format)
*/
void CASPER_ModExp(CASPER_Type *base,
                   const uint8_t *signature,
                   const uint8_t *pubN,
                   size_t wordLen,
                   uint32_t pubE,
                   uint8_t *plaintext);

we use the following code to calculate the RSA as an example:

static const unsigned pubkey0[2048 / 32] = {
    0x232577d1, 0xa1c2d50d, 0x99706557, 0x46c818ab, 0xaa53916b, 0x63f5f64b, 0x93cd68f4, 0x1ed00fb7,
    0xea292749, 0x39de13c1, 0x065b5911, 0x884b13c9, 0xe6f6c061, 0xef47223e, 0x92e9e488, 0x3931a79d,
    0x14861755, 0xde93cc46, 0x1e74bf9a, 0xb4a3d058, 0x2b63c4b1, 0xd37d1bf7, 0x3fd70745, 0x5095a782,
    0xec4bcd7b, 0xbef831fb, 0x7f682470, 0x56a9a012, 0x6136775a, 0x2777c47d, 0x89b3f94a, 0x62fa6f9f,
    0xc97a18ab, 0x55d68409, 0x39007ccb, 0xe3514d48, 0xe817cc0e, 0xafd713ba, 0x14a82e21, 0xe5ff1433,
    0x385a8131, 0x31f2ece8, 0x8d395a2a, 0x85622d91, 0x67634847, 0xb219d21d, 0x1ef8efaa, 0xfaa05682,
    0x109b9a8a, 0x41042b7e, 0x0ebe7f64, 0xdae23bff, 0x5cfd544b, 0x74b9cbf2, 0x9563cafb, 0x462b3911,
    0x16e9cdf4, 0x68ed6d7f, 0xc6e45a20, 0x65838412, 0xa261fc8b, 0xbdd913f2, 0xc1782e4d, 0xbad47a84,
};
static const unsigned plaintext0[2048 / 32] = {
    0x4b4fb4bc, 0x9da3c722, 0x1fa87ba2, 0xf312d3f1, 0xb3823c63, 0x0917140a, 0xa07c69d7, 0xc2c92b88,
    0x7e732102, 0xd3420e56, 0x7c089aa2, 0x518dc5f5, 0xdeb09cc4, 0x9d429cf9, 0x2deca5b4, 0x430bb1a7,
    0xe8fd387c, 0x083ec701, 0x518db8a2, 0x407db831, 0x5b2bf516, 0x570eb451, 0xc4f202a9, 0x77f504da,
    0x5b73edac, 0x61e5667e, 0xf131bd94, 0xf2d3ce56, 0x09c828d6, 0x57ce7f8f, 0xcfba290b, 0xf53c3d7f,
    0x16bd7ae8, 0x6e8ad8fd, 0x7995a8ba, 0x5d2102ef, 0x982a4658, 0x2d362945, 0x2428b8d3, 0xb6c2f765,
    0x608adb30, 0xfe6be10e, 0xdfcd8056, 0x37bbc360, 0x5d00f1a4, 0xbde4493f, 0x9fb4eab5, 0x80a14649,
    0x7a56082c, 0x1caf81b2, 0x21bb7186, 0x53576457, 0xf58300d2, 0xfbfb82b0, 0xf303a568, 0xeb7f0d4d,
    0x2c4b0b4e, 0xaf50cac4, 0x6f9d7808, 0x3f120e32, 0x9fa1cd64, 0x2a94b3ab, 0x95a4908d, 0x70992c9d,
};
static const unsigned signature0[2048 / 32] = {
    0x892b6f74, 0x85c033f9, 0x33ab8b20, 0x74007e6a, 0xf1687e00, 0x96960052, 0x875dbc47, 0xe2d51612,
    0x804bf80e, 0x0bcc5205, 0x5b630d07, 0x741553a4, 0xe77737da, 0xffdd47b3, 0xcad941db, 0xda40f72e,
    0x2a42eb3b, 0xdfd88bb2, 0xadd387fe, 0xaf641538, 0x72ce8a31, 0x965b713d, 0x35e78b46, 0xfee41c44,
    0x7ef74f17, 0x496ddbc7, 0xd9f09955, 0x26eda243, 0x210b25e9, 0x6e032a66, 0x430800e1, 0xabbe7f89,
    0xd339cc87, 0x81cac45c, 0x06e9e6ec, 0x32d5be61, 0x0632d363, 0x5404adb0, 0xa2dad9fa, 0x62dbc7a9,
    0xc299bd0e, 0xcc9ff240, 0x71d5c214, 0x3131e9b3, 0x6a8a974a, 0xc49551d8, 0xe457c1da, 0x45d99126,
    0x451c6b46, 0x51b753f7, 0x1ec0663e, 0x69d2429f, 0x404788b8, 0x8a28dd70, 0xc86f9d1b, 0xcb6bad9a,
    0xd84d8836, 0x37cff304, 0xf4c3ae42, 0x3dce66d0, 0x3fbf9896, 0x028c75dc, 0xa05f626b, 0x7e65b998,
};
static const unsigned pub_e = 0x10001;

static uint8_t plaintext[2048 / 8];

/*******************************************************************************
* Prototypes
******************************************************************************/

/*******************************************************************************
* Code
******************************************************************************/

/*!
* @brief Main function.
*/
int main(void)
{
    /* Init hardware */
    /* attach main clock divide to FLEXCOMM0 (debug console) */
    CLOCK_AttachClk(BOARD_DEBUG_UART_CLK_ATTACH);

    BOARD_InitPins();
    BOARD_BootClockPLL150M();
    BOARD_InitDebugConsole();

/* Initialize CASPER */
CASPER_Init(CASPER);

    /* ModExp test */
    CASPER_ModExp(CASPER, (void *)signature0, (void *)pubkey0, sizeof(plaintext0) / sizeof(uint32_t), pub_e, plaintext);
    TEST_ASSERT(memcmp(plaintext0, plaintext, sizeof(plaintext)) == 0);
    PRINTF("ModExp Test pass.\r\n");

/* ECC tests */

...........................

}

For the above code, the plaintext0[] is 2048, so the above code provides 2048 bits RSA algorthms. But if the plaintext0[] is 3072 bits, I think it is okay.

We provide source code instead of library.

Hope it can help you.

Xiangjun Rong

LPC Microcontrollers中的主题 Does LCP55S6x support RSA-3072 calculation ?

Does LCP55S6x support RSA-3072 calculation ?

Re: Does LCP55S6x support RSA-3072 calculation ?