B4X

Get a JWS Protected Header

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.GetProtectedH, which copies the decoded protected header of a signature into a JsonObject.

Background. The protected header is integrity-protected by the signature. Inspecting it (for example the alg value) is useful before deciding how to validate.

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Dim success As Boolean = False

Dim jws As ChilkatJws
jws.Initialize

'  Load the JWS compact serialization.
Dim jwsCompact As String = "eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>"
success = jws.LoadJws(jwsCompact)
If success = False Then
    Log(jws.LastErrorText)
    Return
End If


'  Copy the decoded protected header of signature 0 into a JsonObject.
Dim json As ChilkatJsonObject
json.Initialize
success = jws.GetProtectedH(0, json)
If success = False Then
    Log(jws.LastErrorText)
    Return
End If


json.EmitCompact = False
Log(json.Emit)