(VBScript) JWE using ECDH-ES+A256KW

See more JSON Web Encryption (JWE) Examples

{
    "kty": "EC",
    "d": "jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c",
    "use": "enc",
    "crv": "P-256",
    "kid": "evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs",
    "x": "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM",
    "y": "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4",
    "alg": "ECDH-ES+A256KW"
}

Also shows how to decrypt.

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.

' Create the following JSON:
' {
'     "kty": "EC",
'     "d": "jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c",
'     "use": "enc",
'     "crv": "P-256",
'     "kid": "evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs",
'     "x": "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM",
'     "y": "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4",
'     "alg": "ECDH-ES+A256KW"
' }

set json = CreateObject("Chilkat.JsonObject")
success = json.UpdateString("kty","EC")
success = json.UpdateString("d","jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c")
success = json.UpdateString("use","enc")
success = json.UpdateString("crv","P-256")
success = json.UpdateString("kid","evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs")
success = json.UpdateString("x","LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM")
success = json.UpdateString("y","voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4")
success = json.UpdateString("alg","ECDH-ES+A256KW")

set pubkey = CreateObject("Chilkat.PublicKey")

success = pubkey.LoadFromString(json.Emit())
If (success = 0) Then
    outFile.WriteLine(pubkey.LastErrorText)
    WScript.Quit
End If

' Build our protected header:

' 	{
' 	  "alg": "ECDH-ES+A256KW",
' 	  "enc": "A256GCM",
' 	  "exp": 1621957030,
' 	  "cty": "NJWT",
' 	  "epk": {
' 	    "kty": "EC",
' 	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
' 	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
' 	    "crv": "BP-256"
' 	  }
' 	}

' Use jwt only for getting the current date/time + 3600 seconds.
set jwt = CreateObject("Chilkat.Jwt")

set jweProtHdr = CreateObject("Chilkat.JsonObject")
success = jweProtHdr.UpdateString("alg","ECDH-ES+A256KW")
success = jweProtHdr.UpdateString("enc","A256GCM")
success = jweProtHdr.UpdateInt("exp",jwt.GenNumericDate(3600))
success = jweProtHdr.UpdateString("cty","NJWT")
success = jweProtHdr.UpdateString("epk.kty","EC")
success = jweProtHdr.UpdateString("epk.x","LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM")
success = jweProtHdr.UpdateString("epk.y","voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4")
success = jweProtHdr.UpdateString("epk.crv","P-256")

set jwe = CreateObject("Chilkat.Jwe")
success = jwe.SetProtectedHeader(jweProtHdr)
success = jwe.SetPublicKey(0,pubkey)

plainText = "This is the text to be encrypted."
strJwe = jwe.Encrypt(plainText,"utf-8")
If (jwe.LastMethodSuccess <> 1) Then
    outFile.WriteLine(jwe.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine(strJwe)

' Let's decrypt...
set privkey = CreateObject("Chilkat.PrivateKey")

success = privkey.LoadJwk(json.Emit())
If (success = 0) Then
    outFile.WriteLine(privkey.LastErrorText)
    WScript.Quit
End If

set jwe2 = CreateObject("Chilkat.Jwe")
success = jwe2.LoadJwe(strJwe)
If (success = 0) Then
    outFile.WriteLine(jwe2.LastErrorText)
    WScript.Quit
End If

success = jwe2.SetPrivateKey(0,privkey)

'  Decrypt.
decryptedText = jwe2.Decrypt(0,"utf-8")
If (jwe2.LastMethodSuccess <> 1) Then
    outFile.WriteLine(jwe2.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine(decryptedText)

outFile.Close