AutoIt

Validate a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses ECDSA P-256 SHA-256 AutoIt

Local $bSuccess = False

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

; This example takes a JSON signature in compact serialization format,
; and uses an ECDSA public key to validate and recover the protected header and payload.

; We only need a public key for signature validation.  This is the ECDSA public key
; that is used:

;      {"kty":"EC", 
;       "crv":"P-256", 
;       "x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU", 
;       "y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" 
;      } 

$oSbPubKey = ObjCreate("Chilkat.StringBuilder")
$oSbPubKey.Append("{""kty"":""EC"",")
$oSbPubKey.Append("""crv"":""P-256"",")
$oSbPubKey.Append("""x"":""f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU"",")
$oSbPubKey.Append("""y"":""x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0""")
$oSbPubKey.Append("}")

$oPubKey = ObjCreate("Chilkat.PublicKey")
$bSuccess = $oPubKey.LoadFromString($oSbPubKey.GetAsString())
If ($bSuccess = False) Then
    ConsoleWrite($oPubKey.LastErrorText & @CRLF)
    Exit
EndIf

$oJws = ObjCreate("Chilkat.Jws")

; Set the ECC public key:
Local $iSignatureIndex = 0
$oJws.SetPublicKey($iSignatureIndex,$oPubKey)

; Load the JWS.
$oSbJws = ObjCreate("Chilkat.StringBuilder")
$oSbJws.Append("eyJhbGciOiJFUzI1NiJ9")
$oSbJws.Append(".")
$oSbJws.Append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt")
$oSbJws.Append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ")
$oSbJws.Append(".")
$oSbJws.Append("DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSA")
$oSbJws.Append("pmWQxfKTUJqPP3-Kg6NU1Q")

$bSuccess = $oJws.LoadJwsSb($oSbJws)
If ($bSuccess = False) Then
    ConsoleWrite($oJws.LastErrorText & @CRLF)
    Exit
EndIf

; Validate the 1st (and only) signature at index 0..
Local $iV = $oJws.Validate($iSignatureIndex)
If ($iV < 0) Then
    ; Perhaps Chilkat was not unlocked or the trial expired..
    ConsoleWrite("Method call failed for some other reason." & @CRLF)
    ConsoleWrite($oJws.LastErrorText & @CRLF)
    Exit
EndIf

If ($iV = 0) Then
    ConsoleWrite("Invalid signature.  The ECC key was incorrect, the JWS was invalid, or both." & @CRLF)
    Exit
EndIf

; If we get here, the signature was validated..
ConsoleWrite("Signature validated." & @CRLF)
ConsoleWrite("--" & @CRLF)

; Recover the original content:
ConsoleWrite("Recovered content:" & @CRLF)
ConsoleWrite($oJws.GetPayload("utf-8") & @CRLF)
ConsoleWrite("--" & @CRLF)

; Examine the protected header:

$oJoseHeader = ObjCreate("Chilkat.JsonObject")
$bSuccess = $oJws.GetProtectedH($iSignatureIndex,$oJoseHeader)
If ($bSuccess = False) Then
    ConsoleWrite($oJws.LastErrorText & @CRLF)
    Exit
EndIf

$oJoseHeader.EmitCompact = False

ConsoleWrite("Protected (JOSE) header:" & @CRLF)
ConsoleWrite($oJoseHeader.Emit() & @CRLF)

; Output:

; 	Signature validated.
; 	--
; 	Recovered content:
; 	{"iss":"joe",
; 	 "exp":1300819380,
; 	 "http://example.com/is_root":true}
; 	--
; 	Protected (JOSE) header:
; 	{ 
; 	  "alg": "ES256"
; 	}