A loader for EC Key Pair

KeyLoader.java

public class KeyLoader {
    private static ECPrivateKey loadPrivateKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
        // generate key: openssl ecparam -genkey -name secp521r1 -noout -out private_key.pem
        // parse key: openssl pkcs8 -topk8 -in .\private_key.pem -out pkcs8_rsa_private_key.pem -nocrypt
        var privateKey = "key string";
        var keyBytes = Base64.getDecoder().decode(privateKey);
        var spec = new PKCS8EncodedKeySpec(keyBytes);
        var kf = KeyFactory.getInstance("EC");
        var key = kf.generatePrivate(spec);
        if (key instanceof ECPrivateKey pk) {
            return pk;
        } else {
            throw new RuntimeException("Type error!");
        }
    }

    private static ECPublicKey loadPublicKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
        // get public key: openssl ec -in private_key.pem -pubout -out public_key.pem
        var publicKey = "key string";
        var keyBytes = Base64.getDecoder().decode(publicKey);
        var spec = new X509EncodedKeySpec(keyBytes);
        var keyFactory = KeyFactory.getInstance("EC");
        var key = keyFactory.generatePublic(spec);
        if (key instanceof ECPublicKey ecPk) {
            return ecPk;
        } else {
            throw new RuntimeException("Type Error!");
        }
    }
}