(Classic ASP) JWS Using HMAC SHA-256

Creates a JSON Web Signatures (JWS) using HMAC SHA-256.

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

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

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<%
' 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.

' First create the JWS Protected Header
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.JsonObject")
set jwsProtHdr = Server.CreateObject("Chilkat.JsonObject")
success = jwsProtHdr.AppendString("typ","JWT")
success = jwsProtHdr.AppendString("alg","HS256")
Response.Write "<pre>" & Server.HTMLEncode( "JWS Protected Header: " & jwsProtHdr.Emit()) & "</pre>"

' Output:
' JWS Protected Header: {"typ":"JWT","alg":"HS256"}

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Jws")
set jws = Server.CreateObject("Chilkat.Jws")

' Set the HMAC key:
hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
signatureIndex = 0
success = jws.SetMacKey(signatureIndex,hmacKey,"base64url")

' Set the protected header:
success = jws.SetProtectedHeader(signatureIndex,jwsProtHdr)

' Set the payload.
bIncludeBom = 0
payloadStr = "In our village, folks say God crumbles up the old moon into stars."
success = jws.SetPayload(payloadStr,"utf-8",bIncludeBom)

' Create the JWS
' By default, the compact serialization is used.
jwsCompact = jws.CreateJws()
If (jws.LastMethodSuccess <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( jws.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "JWS: " & jwsCompact) & "</pre>"

' sample output:
' JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

' Now load the JWS, validate, and recover the original text.
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Jws")
set jws2 = Server.CreateObject("Chilkat.Jws")

' Load the JWS.
success = jws2.LoadJws(jwsCompact)

' Set the MAC key used for validation.
signatureIndex = 0
success = jws2.SetMacKey(signatureIndex,hmacKey,"base64url")

' Validate the 1st (and only) signature at index 0..
v = jws2.Validate(signatureIndex)
If (v < 0) Then
    ' Perhaps Chilkat was not unlocked or the trial expired..
    Response.Write "<pre>" & Server.HTMLEncode( "Method call failed for some other reason.") & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( jws2.LastErrorText) & "</pre>"
    Response.End
End If

If (v = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.") & "</pre>"
    Response.End
End If

' If we get here, the signature was validated..
Response.Write "<pre>" & Server.HTMLEncode( "Signature validated.") & "</pre>"

' Recover the original content:
Response.Write "<pre>" & Server.HTMLEncode( jws2.GetPayload("utf-8")) & "</pre>"

' Examine the protected header:
' joseHeader is a Chilkat.JsonObject
Set joseHeader = jws2.GetProtectedHeader(signatureIndex)
If (jws2.LastMethodSuccess <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( "No protected header found at the given index.") & "</pre>"
    Response.End
End If

joseHeader.EmitCompact = 0

Response.Write "<pre>" & Server.HTMLEncode( "Protected (JOSE) header:") & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( joseHeader.Emit()) & "</pre>"

' Output:

' 	Signature validated.
' 	In our village, folks say God crumbles up the old moon into stars.
' 	Protected (JOSE) header:
' 	{ 
' 	  "typ": "JWT",
' 	  "alg": "HS256"
' 	} 

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