(VBScript) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

' 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.
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.BinData")
set jpgBytes = CreateObject("Chilkat.BinData")
success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")
' Make sure your app checks the success/failure of the call to LoadFile..
outFile.WriteLine("Original JPG size = " & jpgBytes.NumBytes)

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Jwe")
set jwe = CreateObject("Chilkat.Jwe")

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.JsonObject")
set jweProtHdr = CreateObject("Chilkat.JsonObject")
success = jweProtHdr.AppendString("alg","A128KW")
success = jweProtHdr.AppendString("enc","A128CBC-HS256")
success = jwe.SetProtectedHeader(jweProtHdr)

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

' Encrypt and return the JWE in sbJwe:
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.StringBuilder")
set sbJwe = CreateObject("Chilkat.StringBuilder")
success = jwe.EncryptBd(jpgBytes,sbJwe)
If (success <> 1) Then
    outFile.WriteLine(jwe.LastErrorText)
    WScript.Quit
End If

' Show the JWE:
outFile.WriteLine(sbJwe.GetAsString())
outFile.WriteLine("size of JWE: " & sbJwe.Length)

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

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Jwe")
set jwe2 = CreateObject("Chilkat.Jwe")
success = jwe2.LoadJweSb(sbJwe)
If (success <> 1) Then
    outFile.WriteLine(jwe2.LastErrorText)
    WScript.Quit
End If

' Set the AES wrap key.
success = jwe2.SetWrappingKey(0,aesWrappingKey,"base64url")

' Decrypt.
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.BinData")
set jpgOriginal = CreateObject("Chilkat.BinData")
success = jwe2.DecryptBd(0,jpgOriginal)
If (success <> 1) Then
    outFile.WriteLine(jwe2.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Decrypted JPG size = " & jpgOriginal.NumBytes)

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

outFile.WriteLine("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

outFile.Close