Java

RSA Sign an Encoded Hash

See more RSA Examples

Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex). Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Rsa;

public class ChilkatExample {

    public static void main(String[] args) {
        boolean success = false;

        // Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
        // this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

        // Chilkat automatically detects and determines the way in which the HSM is used,
        // which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

        Cert cert = new Cert();

        // Set the token/smartcard PIN prior to loading.
        cert.setSmartCardPin("123456");

        // Specify the certificate by its common name.
        try {
            cert.loadFromSmartcard("cn=chilkat-rsa-2048");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Signing with the private key for this cert: " + cert.getSubjectCN());

        // Create data to be hashed and signed.
        BinData bd = new BinData();
        for (int i = 0; i <= 100; i++) {
            bd.appendEncoded("000102030405060708090A0B0C0D0E0F", "hex");
        }

        Rsa rsa = new Rsa();

        // Use the certificate's private key for signing.
        try {
            rsa.setX509Cert(cert, true);
            success = true;
        } catch (ChilkatException e) {
            success = false;
        }
        if (!success) {
            System.out.println(rsa.getLastErrorText());
            return;
        }

        // We'll first compute the hash and then pass the encoded hash to be signed.
        String sha256_base64 = bd.getHash("sha256", "base64");
        System.out.println("sha256 hash in base64 format: " + sha256_base64);

        // Pass in the base64 hash and return a base64 signature.
        rsa.setEncodingMode("base64");
        String rsaSig_base64 = rsa.signHashENC(sha256_base64, "sha256");
        if (!success) {
            System.out.println(rsa.getLastErrorText());
            return;
        }

        System.out.println("RSA signature as base64: " + rsaSig_base64);
    }
}