(C) Get EC Public Key from EC Private Key

Demonstrates how to get an EC public key from an EC private key.

Note: This example requires Chilkat v11.0.0 or greater.

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#include <C_CkPrivateKey.h>
#include <C_CkPublicKey.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKey privKey;
    HCkPublicKey pubKey;

    success = FALSE;

    // We have an ECC private key...
    // The contents of the private key PEM file look like this:

    // 	-----BEGIN PRIVATE KEY-----
    // 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
    // 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
    // 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
    // 	-----END PRIVATE KEY-----

    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadPemFile(privKey,"qa_data/ecc/secp256r1-key-pkcs8.pem");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkPrivateKey_Dispose(privKey);
        return;
    }

    // Get the public key.
    pubKey = CkPublicKey_Create();
    CkPrivateKey_ToPublicKey(privKey,pubKey);

    // Save the public key to a PEM file.
    success = CkPublicKey_SavePemFile(pubKey,FALSE,"qa_data/ecc/secp256r1-pubkey.pem");
    if (success == FALSE) {
        printf("%s\n",CkPublicKey_lastErrorText(pubKey));
        CkPrivateKey_Dispose(privKey);
        CkPublicKey_Dispose(pubKey);
        return;
    }

    // The contents of the ECC public key PEM file look like this:

    // 	-----BEGIN PUBLIC KEY-----
    // 	MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
    // 	AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
    // 	///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
    // 	NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
    // 	RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
    // 	//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABOVKaiLPKEDChhkA64UEBOXT
    // 	v/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=
    // 	-----END PUBLIC KEY-----

    printf("Success.\n");


    CkPrivateKey_Dispose(privKey);
    CkPublicKey_Dispose(pubKey);

    }