Xojo Plugin

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

Note: This example requires Chilkat v9.5.0.66 or greater.

Xojo Plugin

Dim success As Boolean
success = False

// 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.

Dim plaintext As String
plaintext = "Live long and prosper."

Dim jwe As New Chilkat.Jwe

// First build the JWE Protected Header..
Dim jweProtHdr As New Chilkat.JsonObject
success = jweProtHdr.AppendString("alg","dir")
success = jweProtHdr.AppendString("enc","A128GCM")

// Don't forget to actually provide the protected header to the JWE object:
success = jwe.SetProtectedHeader(jweProtHdr)

// The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
// Given that the "alg" = "dir", we are to directly specify the AES GCM key.
// (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

// Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

// The SetWrappingKey method is also used for "dir" direct keys.
// However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
// which is specified by calling SetWrappingKey with an index of 0.

Dim recipientIndex As Int32
recipientIndex = 0
success = jwe.SetWrappingKey(recipientIndex,"000102030405060708090A0B0C0D0E0F","hex")

// Encrypt and return the JWE:
Dim strJwe As String
strJwe = jwe.Encrypt(plaintext,"utf-8")
If (jwe.LastMethodSuccess <> True) Then
    System.DebugLog(jwe.LastErrorText)
    Return
End If

// Show the JWE we just created:
System.DebugLog(strJwe)

// Decrypt the JWE.
Dim jwe2 As New Chilkat.Jwe
success = jwe2.LoadJwe(strJwe)
If (success <> True) Then
    System.DebugLog(jwe2.LastErrorText)
    Return
End If

success = jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex")

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

System.DebugLog("original text: ")
System.DebugLog(originalPlaintext)

// Sample output:
// eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
// original text: 
// Live long and prosper.