(VB.NET) 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 .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim success As Boolean

' 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"
' }

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

Dim pubkey As New Chilkat.PublicKey

success = pubkey.LoadFromString(json.Emit())
If (success = False) Then
    Debug.WriteLine(pubkey.LastErrorText)
    Exit Sub
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.
Dim jwt As New Chilkat.Jwt

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

Dim jwe As New Chilkat.Jwe
jwe.SetProtectedHeader(jweProtHdr)
jwe.SetPublicKey(0,pubkey)

Dim plainText As String = "This is the text to be encrypted."
Dim strJwe As String = jwe.Encrypt(plainText,"utf-8")
If (jwe.LastMethodSuccess <> True) Then
    Debug.WriteLine(jwe.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(strJwe)


' Let's decrypt...
Dim privkey As New Chilkat.PrivateKey

success = privkey.LoadJwk(json.Emit())
If (success = False) Then
    Debug.WriteLine(privkey.LastErrorText)
    Exit Sub
End If


Dim jwe2 As New Chilkat.Jwe
success = jwe2.LoadJwe(strJwe)
If (success = False) Then
    Debug.WriteLine(jwe2.LastErrorText)
    Exit Sub
End If


jwe2.SetPrivateKey(0,privkey)

'  Decrypt.
Dim decryptedText As String = jwe2.Decrypt(0,"utf-8")
If (jwe2.LastMethodSuccess <> True) Then
    Debug.WriteLine(jwe2.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(decryptedText)