(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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
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")

Dim pubkey As New Chilkat.PublicKey

success = pubkey.LoadFromString(json.Emit())
If (success = False) Then
    System.DebugLog(pubkey.LastErrorText)
    Return
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
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")

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

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

System.DebugLog(strJwe)

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

success = privkey.LoadJwk(json.Emit())
If (success = False) Then
    System.DebugLog(privkey.LastErrorText)
    Return
End If

Dim jwe2 As New Chilkat.Jwe
success = jwe2.LoadJwe(strJwe)
If (success = False) Then
    System.DebugLog(jwe2.LastErrorText)
    Return
End If

success = jwe2.SetPrivateKey(0,privkey)

//  Decrypt.
Dim decryptedText As String
decryptedText = jwe2.Decrypt(0,"utf-8")
If (jwe2.LastMethodSuccess <> True) Then
    System.DebugLog(jwe2.LastErrorText)
    Return
End If

System.DebugLog(decryptedText)