Java Requires Chilkat v11.0.0+

Decrypt S/MIME and Verify S/MIME Signatures

See more MIME Examples

_LANGUAGE_ example to decrypt S/MIME and verify S/MIME signatures. The S/MIME is unwrapped to get the original MIME prior to signing/encrypting. Chilkat2 Java

import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Mime;

public class ChilkatExample {

    public static void main(String[] args) {
        boolean success = false;

        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Mime mime = new Mime();

        // Load an S/MIME message from a file:
        try {
            mime.loadMimeFile("signedMime.txt");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // The ContainsEncryptedParts/ContainsSignedParts methods
        // can be called to determine if the MIME is encrypted and/or signed:
        boolean isEncrypted = mime.containsEncryptedParts();
        boolean isSigned = mime.containsSignedParts();

        // We don't want the "unwrap extras".  You'll see what those
        // are in a few moments...
        mime.setUnwrapExtras(false);

        // To verify the signature, call UnwrapSecurity.  This will
        // verify the signature(s) and decrypt the S/MIME and restore
        // the MIME to the unsigned/unencrypted state.
        // The results of what was found are present in the MIME object's
        // properties, as well as extra header fields that are added
        // to the unwrapped MIME.
        try {
            mime.unwrapSecurity();
        } catch (ChilkatException e) {
            // UnwrapSecurity returns true if all signatures were
            // verified and all parts decrypted.
            System.out.println(e.getLastErrorText());
            return;
        }

        // The mime.UnwrapExtras property controls whether or not
        // these additional fields are added to the unwrapped MIME:
        //
        // X-NumPartsSigned: 1
        // X-SignaturesValid: yes
        // X-NumPartsEncrypted: 1
        // X-Decrypted: no
        //
        // The X-NumPartsSigned/X-SignaturesValid headers are added
        // if the MIME was signed.
        //
        // The X-NumPartsEncrypted/X-Decrypted headers are added
        // if the MIME was encrypted.
        //

        // If the MIME was signed, get the certificate used for signing.
        if (isSigned) {
            Cert signerCert = new Cert();

            // The NumSignerCerts property indicates how many certificates
            // were used for signing.  This example will assume the value is 1.
            // To get the 1st signer cert, call LastSignerCert with an index of 0:
            try {
                mime.lastSignerCert(0, signerCert);
                success = true;
            } catch (ChilkatException e) {
                success = false;
            }
            if (success) {
                System.out.println("**** Signer Cert: " + signerCert.getSubjectCN());
            }
        }

        // If the MIME was encrypted, get the certificate used for decryption
        if (isEncrypted) {
            // The NumDecryptCerts property indicates how many certificates
            // were used for decrypting.  This example will assume the value is 1.
            // To get the 1st decrypt cert, call LastDecryptCert with an index of 0:
            Cert decryptCert = new Cert();
            try {
                mime.lastDecryptCert(0, decryptCert);
                success = true;
            } catch (ChilkatException e) {
                success = false;
            }
            if (success) {
                System.out.println("**** Decrypt Cert: " + decryptCert.getSubjectCN());
            }
        }

        // Display the unwrapped MIME:
        System.out.println(mime.getMime());

        // Save the unwrapped MIME to a file:
        mime.saveMime("unwrappedMime.txt");
    }
}