(Java) Sign JSON (or any Text) to Create a Detached PKCS7 Signature

Demonstrates how to sign JSON or any string using a certificate + private key from a .p12/.pfx to create a detached PKCS7 signature. (A detached signature is one that does not embed the original signed data.)

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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[])
  {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkCrypt2 crypt = new CkCrypt2();

    CkCert cert = new CkCert();
    boolean success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123");
    if (success != true) {
        System.out.println(cert.lastErrorText());
        return;
        }

    // Tell the crypt component to use this cert.
    success = crypt.SetSigningCert(cert);
    if (success != true) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    crypt.put_HashAlgorithm("sha256");

    // By default, all the certs in the chain of authentication are included in the signature.
    // If desired, we can choose to only include the signing certificate:
    crypt.put_IncludeCertChain(false);

    // Create the detached signature, which does NOT contain the original data.
    // To create a PKCS7 signature that contains the original data, see CAdES Sign JSON
    crypt.put_Charset("utf-8");
    CkByteData detachedSig = new CkByteData();
    String stringToSign = "{ \"abc\": 123}";
    success = crypt.SignString(stringToSign,detachedSig);
    if (crypt.get_LastMethodSuccess() == false) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    // Verify the signature against the original data.
    boolean verified = crypt.VerifyString(stringToSign,detachedSig);
    if (verified == false) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    System.out.println("Success!");
  }
}