C++

JWE with Binary Data

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE that contains a binary payload (such as a JPG image).

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

C++

#include <CkBinData.h>
#include <CkJwe.h>
#include <CkJsonObject.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    bool success = false;

    // 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.

    // Load a JPG file that will be the JWE payload.
    CkBinData jpgBytes;
    success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg");
    // Make sure your app checks the success/failure of the call to LoadFile..
    std::cout << "Original JPG size = " << jpgBytes.get_NumBytes() << "\r\n";

    CkJwe jwe;

    CkJsonObject jweProtHdr;
    jweProtHdr.AppendString("alg","A128KW");
    jweProtHdr.AppendString("enc","A128CBC-HS256");
    jwe.SetProtectedHeader(jweProtHdr);

    const char *aesWrappingKey = "GawgguFyGrWKav7AX4VKUg";
    jwe.SetWrappingKey(0,aesWrappingKey,"base64url");

    // Encrypt and return the JWE in sbJwe:
    CkStringBuilder sbJwe;
    success = jwe.EncryptBd(jpgBytes,sbJwe);
    if (success != true) {
        std::cout << jwe.lastErrorText() << "\r\n";
        return;
    }

    // Show the JWE:
    std::cout << sbJwe.getAsString() << "\r\n";
    std::cout << "size of JWE: " << sbJwe.get_Length() << "\r\n";

    // ---------------------------------------------------------
    // Decrypt to get the original JPG file..

    CkJwe jwe2;
    success = jwe2.LoadJweSb(sbJwe);
    if (success != true) {
        std::cout << jwe2.lastErrorText() << "\r\n";
        return;
    }

    // Set the AES wrap key.
    jwe2.SetWrappingKey(0,aesWrappingKey,"base64url");

    // Decrypt.
    CkBinData jpgOriginal;
    success = jwe2.DecryptBd(0,jpgOriginal);
    if (success != true) {
        std::cout << jwe2.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Decrypted JPG size = " << jpgOriginal.get_NumBytes() << "\r\n";

    // Save the decrypted JPG to a file.
    success = jpgOriginal.WriteFile("qa_output/jwe_decrypted_starfish.jpg");

    std::cout << "success = " << success << "\r\n";

    // The output of this program, when tested, was:
    // Original JPG size = 6229
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.9YFz_wteV ... 7Et3hKhpxnKEXw
    // size of JWE: 8473
    // Decrypted JPG size = 6229
    // success = True
    }