Java

Check if a MIME Entity is Signed (S/MIME)

Demonstrates the Chilkat Mime.IsSigned method, which returns whether the entity is a complete CMS/PKCS #7 signed S/MIME wrapper, including detached multipart/signed and opaque forms. It takes no arguments.

Note: The file path is relative to the application's current working directory. Absolute paths may also be used. Supply the path to your own file.

Background: Before verifying a signature you need to know one is present, and this is the check. A signed S/MIME message comes in two shapes — detached (multipart/signed, signature alongside the content) and opaque (application/pkcs7-mime, content wrapped inside the signature) — and this recognizes both. Follow a true result with Verify.

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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;

    //  Demonstrates the Mime.IsSigned method, which returns whether the entity is a complete CMS/PKCS #7 signed S/MIME wrapper.  It takes no arguments.

    CkMime mime = new CkMime();
    success = mime.LoadMimeFile("qa_data/signed.eml");
    if (success == false) {
        System.out.println(mime.lastErrorText());
        return;
        }

    if (mime.IsSigned()) {
        System.out.println("This is a signed S/MIME message.");
        }
    else {
        System.out.println("This is not a signed S/MIME message.");
        }
  }
}