C#

Get EC Public Key from EC Private Key

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

bool 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-----

Chilkat.PrivateKey privKey = new Chilkat.PrivateKey();
success = privKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem");
if (success == false) {
    Debug.WriteLine(privKey.LastErrorText);
    return;
}

// Get the public key.
Chilkat.PublicKey pubKey = new Chilkat.PublicKey();
privKey.ToPublicKey(pubKey);

// Save the public key to a PEM file.
success = pubKey.SavePemFile(false,"qa_data/ecc/secp256r1-pubkey.pem");
if (success == false) {
    Debug.WriteLine(pubKey.LastErrorText);
    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-----

Debug.WriteLine("Success.");