(Java) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original 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 requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

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

    CkFileAccess fac = new CkFileAccess();

    CkByteData fileBytes = new CkByteData();
    success = fac.ReadEntireFile("qa_data/pdf/sample.pdf",fileBytes);
    if (fac.get_LastMethodSuccess() != true) {
        System.out.println(fac.lastErrorText());
        return;
        }

    CkCrypt2 crypt = new CkCrypt2();

    success = crypt.SetSigningCert(cert);

    // We can sign any type of file.

    CkByteData sigBytes = new CkByteData();
    success = crypt.OpaqueSignBytes(fileBytes,sigBytes);
    if (crypt.get_LastMethodSuccess() != true) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    success = fac.WriteEntireFile("qa_output/sample.pdf.p7m",sigBytes);
    if (fac.get_LastMethodSuccess() != true) {
        System.out.println(fac.lastErrorText());
        return;
        }

    // We can verify the opaque signature and extract the original data like this
    CkByteData originalData = new CkByteData();
    success = crypt.OpaqueVerifyBytes(sigBytes,originalData);
    if (crypt.get_LastMethodSuccess() != true) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    success = fac.WriteEntireFile("qa_output/sample.pdf",originalData);
    if (fac.get_LastMethodSuccess() != true) {
        System.out.println(fac.lastErrorText());
        return;
        }

    System.out.println("Signature is verified and the original data was extracted.");
  }
}