(C# UWP/WinRT) JWE with Binary Data

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.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

// 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.

bool success;

// Load a JPG file that will be the JWE payload.
Chilkat.BinData jpgBytes = new Chilkat.BinData();
success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg");
// Make sure your app checks the success/failure of the call to LoadFile..
Debug.WriteLine("Original JPG size = " + Convert.ToString(jpgBytes.NumBytes));

Chilkat.Jwe jwe = new Chilkat.Jwe();

Chilkat.JsonObject jweProtHdr = new Chilkat.JsonObject();
jweProtHdr.AppendString("alg","A128KW");
jweProtHdr.AppendString("enc","A128CBC-HS256");
jwe.SetProtectedHeader(jweProtHdr);

string aesWrappingKey = "GawgguFyGrWKav7AX4VKUg";
jwe.SetWrappingKey(0,aesWrappingKey,"base64url");

// Encrypt and return the JWE in sbJwe:
Chilkat.StringBuilder sbJwe = new Chilkat.StringBuilder();
success = jwe.EncryptBd(jpgBytes,sbJwe);
if (success != true) {
    Debug.WriteLine(jwe.LastErrorText);
    return;
}

// Show the JWE:
Debug.WriteLine(sbJwe.GetAsString());
Debug.WriteLine("size of JWE: " + Convert.ToString(sbJwe.Length));

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

Chilkat.Jwe jwe2 = new Chilkat.Jwe();
success = jwe2.LoadJweSb(sbJwe);
if (success != true) {
    Debug.WriteLine(jwe2.LastErrorText);
    return;
}

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

// Decrypt.
Chilkat.BinData jpgOriginal = new Chilkat.BinData();
success = jwe2.DecryptBd(0,jpgOriginal);
if (success != true) {
    Debug.WriteLine(jwe2.LastErrorText);
    return;
}

Debug.WriteLine("Decrypted JPG size = " + Convert.ToString(jpgOriginal.NumBytes));

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

Debug.WriteLine("success = " + Convert.ToString(success));

// 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