(PowerBuilder) Validate JWS Using HMAC SHA-256

Validates a JSON Web Signature (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
integer li_Success
oleobject loo_Jws
string ls_HmacKey
integer li_SignatureIndex
string ls_JwsCompact
integer v
oleobject loo_JoseHeader

li_Success = 0

// 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 a MAC key to validate and recover the protected header and payload.

loo_Jws = create oleobject
li_rc = loo_Jws.ConnectToNewObject("Chilkat.Jws")
if li_rc < 0 then
    destroy loo_Jws
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Set the HMAC key:
ls_HmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
li_SignatureIndex = 0
loo_Jws.SetMacKey(li_SignatureIndex,ls_HmacKey,"base64url")

// Load the JWS.
ls_JwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
li_Success = loo_Jws.LoadJws(ls_JwsCompact)

// Validate the 1st (and only) signature at index 0..
v = loo_Jws.Validate(li_SignatureIndex)
if v < 0 then
    // Perhaps Chilkat was not unlocked or the trial expired..
    Write-Debug "Method call failed for some other reason."
    Write-Debug loo_Jws.LastErrorText
    destroy loo_Jws
    return
end if

if v = 0 then
    Write-Debug "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both."
    destroy loo_Jws
    return
end if

// If we get here, the signature was validated..
Write-Debug "Signature validated."

// Recover the original content:
Write-Debug "Recovered content:"
Write-Debug loo_Jws.GetPayload("utf-8")

// Examine the protected header:

loo_JoseHeader = create oleobject
li_rc = loo_JoseHeader.ConnectToNewObject("Chilkat.JsonObject")

li_Success = loo_Jws.GetProtectedH(li_SignatureIndex,loo_JoseHeader)
if li_Success = 0 then
    Write-Debug loo_Jws.LastErrorText
    destroy loo_Jws
    destroy loo_JoseHeader
    return
end if

loo_JoseHeader.EmitCompact = 0

Write-Debug "Protected (JOSE) header:"
Write-Debug loo_JoseHeader.Emit()

// Output:

// 	Signature validated.
// 	Recovered content:
// 	{"iss":"joe",
// 	 "exp":1300819380,
// 	 "http://example.com/is_root":true}
// 	Protected (JOSE) header:
// 	{ 
// 	  "typ": "JWT",
// 	  "alg": "HS256"
// 	}


destroy loo_Jws
destroy loo_JoseHeader