Java

Encrypt a file to a PKCS7 encrypted message using multiple certificates from different users

See more Encryption Examples

Demonstrates how to encrypt a file to a PKCS7 encrypted message using multiple certificates from different users. Any one of the users can decrypt using his/her own certificate + private key.

Note: When doing public key encryption, it is the public key that is used to encrypt. The private key is required for decryption.

Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Crypt2 crypt = new Crypt2();

        // Tell the crypt object to use 3 certificates.
        // Do this by calling AddEncryptCert for each certificate.

        // Load a digital certificate.
        // We don't need the private key for encryption.
        // Only the public key is needed (which is included in a certificate).
        Cert cert1 = new Cert();
        cert1.loadFromFile("qa_data/user1/cert_user1.pem");
        // Assume success for the example, but make sure your application checks for success/failure...
        crypt.addEncryptCert(cert1);

        Cert cert2 = new Cert();
        cert2.loadFromFile("qa_data/user2/cert_user2.pem");
        crypt.addEncryptCert(cert2);

        Cert cert3 = new Cert();
        cert3.loadFromFile("qa_data/user3/cert_user3.pem");
        crypt.addEncryptCert(cert3);

        // Indicate that we want PKI encryption (i.e. public-key infrastructure)
        // to produce a CMS message (Cryptographic Message Syntax/PKCS7),
        // that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
        // bulk encryption.
        crypt.setCryptAlgorithm("pki");
        crypt.setPkcs7CryptAlg("aes");
        crypt.setKeyLength(128);
        crypt.setOaepHash("sha256");
        crypt.setOaepPadding(true);

        // Load the file to be encrypted...
        BinData fileData = new BinData();
        fileData.loadFile("qa_data/jpg/penguins.jpg");
        // Your app should check for success/failure..

        // Encrypt the data.  The contents of the fileData object are replaced with the PKCS7 encrypted message.
        try {
            crypt.encryptBd(fileData);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Save the PKCS7 encrypted message to a file..
        fileData.writeFile("qa_output/pkcs7_encrypted.p7");

        // Now indicate that the PKCS7 output is to be returned in the base64 encoding.
        crypt.setEncodingMode("base64");

        System.out.println("OK.");
    }
}