Xojo Plugin

JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

This example demonstrates creating a JCE with AES GCM key wrap. 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.

Dim plaintext As String
plaintext = "My text to enrypt"

Dim jwe As New Chilkat.Jwe

// First build the JWE Protected Header: 

//         {
//             "alg": "A256GCMKW",
//             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
//             "tag": "kfPduVQ3T3H6vnewt--ksw",
//             "iv": "KkYT0GX_2jHlfqN_",
//             "enc": "A128CBC-HS256"
//         }

Dim jweProtHdr As New Chilkat.JsonObject
success = jweProtHdr.AppendString("alg","A256GCMKW")
// kid is optional
success = jweProtHdr.AppendString("kid","18ec08e1-bfa9-4d95-b205-2b4dd1d4321d")
// tag is optional
success = jweProtHdr.AppendString("tag","kfPduVQ3T3H6vnewt--ksw")
success = jweProtHdr.AppendString("enc","A256GCM")
// the iv should be 16 random chars.
Dim prng As New Chilkat.Prng
success = jweProtHdr.AppendString("iv",prng.RandomString(16,True,True,True))
success = jwe.SetProtectedHeader(jweProtHdr)

System.DebugLog("JWE Protected Header: " + jweProtHdr.Emit())
System.DebugLog("--")

// Given that we have 256-bit AES, our key should be 32 bytes.
// The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
// ascii chars directly as the key.
Dim aesWrappingKey As String
aesWrappingKey = "2baf4f730f5e4542b428593ef9cceb0e"
success = jwe.SetWrappingKey(0,aesWrappingKey,"ascii")

// 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 that was just produced.
// 1) Load the JWE.
// 2) Set the AES wrapping key.
// 3) Decrypt.
Dim jwe2 As New Chilkat.Jwe
success = jwe2.LoadJwe(strJwe)
If (success <> True) Then
    System.DebugLog(jwe2.LastErrorText)
    Return
End If

// Set the AES wrap key.  Important to use "ascii"
success = jwe2.SetWrappingKey(0,aesWrappingKey,"ascii")

// 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)