07_ECDH

Example code to Compute Shared secret between both the parties. More...

Collaboration diagram for 07_ECDH:

Example code to Compute Shared secret between both the parties.

/* Reader Library Headers. */
#include <phKeyStore.h>
#include <phCryptoASym.h>
 
/* Standard Header. */
#include <string.h>
 
#define CHECK_SUCCESS(x)                                                                             \
     if ( (x) != PH_ERR_SUCCESS )                                                                    \
     {                                                                                               \
             printf ( "\n\n" );                                                                      \
             printf ( "An error occurred: (0x%04X)\n", (x) );                                        \
             printf ( "Pressing any key will exit the demo.\n" );                                    \
             _getch ();                                                                              \
             return 0;                                                                               \
     }
 
#define KEY_ENTRIES              10
#define KEY_VERSION_PAIRS        3 * KEY_ENTRIES
#define KEY_USAGE_COUNTER        15
 
#define TRUE PH_ON
#define FALSE PH_OFF
 
#define KEY_ADDRESS              1
 
#define KEY_PAIR_PRIVATE_KEY     0
#define KEY_PAIR_PUBLIC_KEY      1
 
/* Variables */
phStatus_t wStatus = 0;
uint8_t aKey[256];
uint16_t wKeyLen = 0;
uint16_t wOption = 0;
uint8_t aSharedSecret[64];
uint16_t wSharedSecretLen = 0;
uint8_t aPublicKey[] =
{
     0x04, 0xC4, 0x18, 0x7C, 0x26, 0xA5, 0x95, 0xB1, 0x8B, 0x37, 0x03, 0x31, 0x2D, 0x80, 0x12, 0x99,
     0x9B, 0x88, 0xEB, 0x28, 0xBD, 0xB4, 0x1F, 0x30, 0x11, 0x28, 0x3D, 0xD8, 0x06, 0xEC, 0xDB, 0x09,
     0x24, 0x1B, 0xA9, 0x9D, 0x61, 0x2D, 0xA5, 0x4A, 0x6E, 0xAF, 0x14, 0x0F, 0x80, 0xAB, 0x5B, 0x19,
     0xE4, 0xBA, 0x66, 0x53, 0x5D, 0x12, 0xBE, 0x85, 0x3C, 0x98, 0x76, 0x7A, 0xDF, 0x7C, 0x13, 0x0C,
     0x1A
};
 
phCryptoASym_Sw_DataParams_t stCryptoASym;
phKeyStore_Sw_DataParams_t stKeyStore;
phKeyStore_Sw_KeyEntry_t aKeyEntry[KEY_ENTRIES];
phKeyStore_Sw_KeyVersionPair_t aKeyVersion[KEY_VERSION_PAIRS];
phKeyStore_Sw_KUCEntry_t aKeyUsageCounter[KEY_USAGE_COUNTER];
 
/* Initialize software keystore component. */
CHECK_SUCCESS(phKeyStore_Sw_Init(&stKeyStore, sizeof(stKeyStore), aKeyEntry, KEY_ENTRIES, aKeyVersion, 2,
     aKeyUsageCounter, KEY_USAGE_COUNTER), TRUE);
 
/* Initialize ASymmetric component. */
CHECK_SUCCESS(phCryptoASym_Sw_Init(&stCryptoASym, sizeof(stCryptoASym), &stKeyStore, aInternalBuffer, wInternalBuffSize), TRUE);
 
/* Generate Keypair
 *   Here ECC key type with SECP256R1 as Curve are used for Key Pair generation.
 */
CHECK_SUCCESS(phCryptoASym_GenerateKeyPair(&stCryptoASym, PH_CRYPTOASYM_KEYMODE_EPHEMERAL, PH_CRYPTOASYM_KEY_TYPE_ECC,
     PH_CRYPTOASYM_CURVE_BY_NAME, (uint8_t *) PH_CRYPTOASYM_CURVE_NAME_SECP256R1,
     (uint16_t) strlen(PH_CRYPTOASYM_CURVE_NAME_SECP256R1)), TRUE);
 
/* Export and print Private key. */
printf("\tExporting Keys in Uncompressed Binary format (BigEndian).\n");
wOption = (uint16_t) (PH_CRYPTOASYM_PRIVATE_KEY | PH_CRYPTOASYM_KEY_FORMAT_BIN);
CHECK_SUCCESS(phCryptoASym_ExportKey(&stCryptoASym, wOption, ( uint16_t )sizeof(aKey), aKey, &wKeyLen), TRUE);
printf("\tPrivate Key: ");
PrintData(aKey, wKeyLen, "%02X ", "\n\n");
 
/* Print Public Key */
printf("\tPublic Key: ");
PrintData(aPublicKey, ( uint16_t )sizeof(aPublicKey), "%02X ", "\n\n\n");
 
/* Compute Shared Secret (ECDH) */
CHECK_SUCCESS(phCryptoASym_SharedSecret(&stCryptoASym, PH_CRYPTOASYM_KEY_FORMAT_BIN, aPublicKey, ( uint16_t )sizeof(aPublicKey),
     aSharedSecret,, &wSharedSecretLen), TRUE);
 
printf("\tShared Secret: ");
PrintData(aSharedSecret, wSharedSecretLen, "%02X ", "\n\n\n");
 
 
 
 
 
 
/* Function to print the bytes. */
void PrintData(uint8_t* pBuffer, uint32_t dwLength, char* pFormat, char* pSpecialChar)
{
 uint32_t dwSplit_Count = 128;
 uint32_t dwIndex1 = 0;
 uint32_t dwIndex2 = 0;
 
 for(dwIndex1 = 0; dwIndex1 < dwLength;dwIndex1++)
 {
     printf(pFormat, pBuffer[dwIndex1]);
 
     dwIndex2++;
     if(dwIndex2 > (dwSplit_Count - 1))
     {
         printf("\n\t                      ");
         dwIndex2 = 0;
     }
 }
 
 printf(pSpecialChar);
}