(C) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

Chilkat C/C++ Library Downloads
MS Visual C/C++ C++ Builder Linux C/C++ Alpine Linux C/C++	MacOS C/C++ iOS C/C++ Android C/C++ MinGW C/C++

#include <C_CkPrivateKey.h>
#include <C_CkStringBuilder.h>

void ChilkatSample(void)
    {
    HCkPrivateKey privKey;
    BOOL success;
    HCkStringBuilder sbPubKeyHex;
    const char *privKeyHex;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // Load an EC key from some format..
    privKey = CkPrivateKey_Create();

    // This loads an ECDSA key from an unencrypted PEM file (no password required).
    success = CkPrivateKey_LoadAnyFormatFile(privKey,"qa_data/ecc/openssl_ecc_privKey.pem","");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkPrivateKey_Dispose(privKey);
        return;
    }

    // The key type should be "ecc" to indicate an EC key.
    printf("key type = %s\n",CkPrivateKey_keyType(privKey));

    // What is the size of the private key in bits?
    printf("size in bits = %d\n",CkPrivateKey_getBitLength(privKey));

    // Get the private and public EC key parts in raw hex format:
    sbPubKeyHex = CkStringBuilder_Create();
    privKeyHex = CkPrivateKey_getRawHex(privKey,sbPubKeyHex);

    // If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).
    printf("private key = %s\n",privKeyHex);

    // The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)
    printf("public key = %s\n",CkStringBuilder_getAsString(sbPubKeyHex));

    // Sample output:
    // key type = ecc
    // size in bits = 256
    // private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
    // public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a


    CkPrivateKey_Dispose(privKey);
    CkStringBuilder_Dispose(sbPubKeyHex);

    }