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JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

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

Local $bSuccess = False

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

Local $sPlaintext = "My text to enrypt"

$oJwe = ObjCreate("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"
;         }

$oJweProtHdr = ObjCreate("Chilkat.JsonObject")
$oJweProtHdr.AppendString("alg","A256GCMKW")
; kid is optional
$oJweProtHdr.AppendString("kid","18ec08e1-bfa9-4d95-b205-2b4dd1d4321d")
; tag is optional
$oJweProtHdr.AppendString("tag","kfPduVQ3T3H6vnewt--ksw")
$oJweProtHdr.AppendString("enc","A256GCM")
; the iv should be 16 random chars.
$oPrng = ObjCreate("Chilkat.Prng")
$oJweProtHdr.AppendString("iv",$oPrng.RandomString(16,True,True,True))
$oJwe.SetProtectedHeader($oJweProtHdr)

ConsoleWrite("JWE Protected Header: " & $oJweProtHdr.Emit() & @CRLF)
ConsoleWrite("--" & @CRLF)

; 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.
Local $sAesWrappingKey = "2baf4f730f5e4542b428593ef9cceb0e"
$oJwe.SetWrappingKey(0,$sAesWrappingKey,"ascii")

; Encrypt and return the JWE:
Local $strJwe = $oJwe.Encrypt($sPlaintext,"utf-8")
If ($oJwe.LastMethodSuccess <> True) Then
    ConsoleWrite($oJwe.LastErrorText & @CRLF)
    Exit
EndIf

; Show the JWE we just created:
ConsoleWrite($strJwe & @CRLF)

; Decrypt the JWE that was just produced.
; 1) Load the JWE.
; 2) Set the AES wrapping key.
; 3) Decrypt.
$oJwe2 = ObjCreate("Chilkat.Jwe")
$bSuccess = $oJwe2.LoadJwe($strJwe)
If ($bSuccess <> True) Then
    ConsoleWrite($oJwe2.LastErrorText & @CRLF)
    Exit
EndIf

; Set the AES wrap key.  Important to use "ascii"
$oJwe2.SetWrappingKey(0,$sAesWrappingKey,"ascii")

; Decrypt.
Local $sOriginalPlaintext = $oJwe2.Decrypt(0,"utf-8")
If ($oJwe2.LastMethodSuccess <> True) Then
    ConsoleWrite($oJwe2.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("original text: " & @CRLF)
ConsoleWrite($sOriginalPlaintext & @CRLF)