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). Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    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.

    CkCert cert = new CkCert();

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

    //  Specify the certificate by its common name.
    success = cert.LoadFromSmartcard("cn=chilkat-rsa-2048");
    if (success == false) {
        System.out.println(cert.lastErrorText());
        return;
        }

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

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

    CkRsa rsa = new CkRsa();

    //  Use the certificate's private key for signing.
    success = rsa.SetX509Cert(cert,true);
    if (success == false) {
        System.out.println(rsa.lastErrorText());
        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.put_EncodingMode("base64");
    String rsaSig_base64 = rsa.signHashENC(sha256_base64,"sha256");
    if (success == false) {
        System.out.println(rsa.lastErrorText());
        return;
        }

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