Java

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Jwe;

public class ChilkatExample {

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

        // Note: This example requires Chilkat v9.5.0.66 or greater.

        String plaintext = "Live long and prosper.";

        Jwe jwe = new Jwe();

        // First build the JWE Protected Header..
        JsonObject jweProtHdr = new JsonObject();
        jweProtHdr.appendString("alg", "dir");
        jweProtHdr.appendString("enc", "A128GCM");

        // Don't forget to actually provide the protected header to the JWE object:
        jwe.setProtectedHeader(jweProtHdr);

        // The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
        // Given that the "alg" = "dir", we are to directly specify the AES GCM key.
        // (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

        // Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

        // The SetWrappingKey method is also used for "dir" direct keys.
        // However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
        // which is specified by calling SetWrappingKey with an index of 0.

        int recipientIndex = 0;
        jwe.setWrappingKey(recipientIndex, "000102030405060708090A0B0C0D0E0F", "hex");

        // Encrypt and return the JWE:
        String strJwe;
        try {
            strJwe = jwe.encrypt(plaintext, "utf-8");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Show the JWE we just created:
        System.out.println(strJwe);

        // Decrypt the JWE.
        Jwe jwe2 = new Jwe();
        String originalPlaintext;
        try {
            jwe2.loadJwe(strJwe);

            jwe2.setWrappingKey(0, "000102030405060708090A0B0C0D0E0F", "hex");

            // Decrypt.
            originalPlaintext = jwe2.decrypt(0, "utf-8");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("original text: ");
        System.out.println(originalPlaintext);

        // Sample output:
        // eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
        // original text:
        // Live long and prosper.
    }
}