(Java) Apple Keychain - Create RSA Signature

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Using an RSA private key stored in the Apple Keychain, create a signature by signing the SHA-256 hash of the provided string, then return the signature encoded in Base64 format.

Note: This example requires Chilkat v10.0.0 or greater.

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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();

    // On MacOS and iOS, the LoadByCommonName function will search the Apple Keychain for the matching certificate.

    // A digital certificate's Common Name (CN) is a field in the certificate that specifies the name of the entity the 
    // certificate is issued to. It is often used to identify the domain name, hostname, or organization the certificate represents. 

    // For example:
    // - In an SSL/TLS certificate for a website, the CN typically contains the domain name (e.g., "www.example.com").
    // - For certificates representing individuals or organizations, the CN might include the person's name or the organization's name.

    // The CN is part of the certificate's Subject field and is crucial for verifying that the certificate corresponds 
    // to the intended entity, especially in SSL/TLS communications.

    boolean success = cert.LoadByCommonName("Example, Inc.");
    if (success == false) {
        System.out.println(cert.lastErrorText());
        return;
        }

    CkRsa rsa = new CkRsa();
    success = rsa.SetX509Cert(cert,true);
    if (success == false) {
        System.out.println(rsa.lastErrorText());
        return;
        }

    // Generate an RSA signature by signing the SHA-256 hash of the provided string, 
    // then return the signature encoded in Base64 format.
    rsa.put_EncodingMode("base64");
    String sigBase64 = rsa.signStringENC("to be signed","sha256");
    if (rsa.get_LastMethodSuccess() == false) {
        System.out.println(rsa.lastErrorText());
        return;
        }

    System.out.println("RSA Signature:");
    System.out.println(sigBase64);
  }
}