(Go) 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.

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    // 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.

    var success bool

    // Load a JPG file that will be the JWE payload.
    jpgBytes := chilkat.NewBinData()
    success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")
    // Make sure your app checks the success/failure of the call to LoadFile..
    fmt.Println("Original JPG size = ", jpgBytes.NumBytes())

    jwe := chilkat.NewJwe()

    jweProtHdr := chilkat.NewJsonObject()
    jweProtHdr.AppendString("alg","A128KW")
    jweProtHdr.AppendString("enc","A128CBC-HS256")
    jwe.SetProtectedHeader(jweProtHdr)

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

    // Encrypt and return the JWE in sbJwe:
    sbJwe := chilkat.NewStringBuilder()
    success = jwe.EncryptBd(jpgBytes,sbJwe)
    if success != true {
        fmt.Println(jwe.LastErrorText())
        jpgBytes.DisposeBinData()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJwe.DisposeStringBuilder()
        return
    }

    // Show the JWE:
    fmt.Println(*sbJwe.GetAsString())
    fmt.Println("size of JWE: ", sbJwe.Length())

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

    jwe2 := chilkat.NewJwe()
    success = jwe2.LoadJweSb(sbJwe)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        jpgBytes.DisposeBinData()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJwe.DisposeStringBuilder()
        jwe2.DisposeJwe()
        return
    }

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

    // Decrypt.
    jpgOriginal := chilkat.NewBinData()
    success = jwe2.DecryptBd(0,jpgOriginal)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        jpgBytes.DisposeBinData()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJwe.DisposeStringBuilder()
        jwe2.DisposeJwe()
        jpgOriginal.DisposeBinData()
        return
    }

    fmt.Println("Decrypted JPG size = ", jpgOriginal.NumBytes())

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

    fmt.Println("success = ", 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

    jpgBytes.DisposeBinData()
    jwe.DisposeJwe()
    jweProtHdr.DisposeJsonObject()
    sbJwe.DisposeStringBuilder()
    jwe2.DisposeJwe()
    jpgOriginal.DisposeBinData()