(PowerBuilder) 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

integer li_rc
integer li_Success
oleobject loo_JwsProtHdr
oleobject loo_Jws
string ls_HmacKey
integer li_SignatureIndex
integer li_BIncludeBom
string ls_PayloadStr
string ls_JwsCompact
oleobject loo_Jws2
integer v
oleobject loo_JoseHeader

// 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
loo_JwsProtHdr = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JwsProtHdr.ConnectToNewObject("Chilkat.JsonObject")
if li_rc < 0 then
    destroy loo_JwsProtHdr
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_JwsProtHdr.AppendString("typ","JWT")
loo_JwsProtHdr.AppendString("alg","HS256")
Write-Debug "JWS Protected Header: " + loo_JwsProtHdr.Emit()

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

loo_Jws = create oleobject
// Use "Chilkat_9_5_0.Jws" for versions of Chilkat < 10.0.0
li_rc = loo_Jws.ConnectToNewObject("Chilkat.Jws")

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

// Set the protected header:
loo_Jws.SetProtectedHeader(li_SignatureIndex,loo_JwsProtHdr)

// Set the payload.
li_BIncludeBom = 0
ls_PayloadStr = "In our village, folks say God crumbles up the old moon into stars."
loo_Jws.SetPayload(ls_PayloadStr,"utf-8",li_BIncludeBom)

// Create the JWS
// By default, the compact serialization is used.
ls_JwsCompact = loo_Jws.CreateJws()
if loo_Jws.LastMethodSuccess <> 1 then
    Write-Debug loo_Jws.LastErrorText
    destroy loo_JwsProtHdr
    destroy loo_Jws
    return
end if

Write-Debug "JWS: " + ls_JwsCompact

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

// Now load the JWS, validate, and recover the original text.
loo_Jws2 = create oleobject
// Use "Chilkat_9_5_0.Jws" for versions of Chilkat < 10.0.0
li_rc = loo_Jws2.ConnectToNewObject("Chilkat.Jws")

// Load the JWS.
li_Success = loo_Jws2.LoadJws(ls_JwsCompact)

// Set the MAC key used for validation.
li_SignatureIndex = 0
loo_Jws2.SetMacKey(li_SignatureIndex,ls_HmacKey,"base64url")

// Validate the 1st (and only) signature at index 0..
v = loo_Jws2.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_Jws2.LastErrorText
    destroy loo_JwsProtHdr
    destroy loo_Jws
    destroy loo_Jws2
    return
end if

if v = 0 then
    Write-Debug "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both."
    destroy loo_JwsProtHdr
    destroy loo_Jws
    destroy loo_Jws2
    return
end if

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

// Recover the original content:
Write-Debug loo_Jws2.GetPayload("utf-8")

// Examine the protected header:
loo_JoseHeader = loo_Jws2.GetProtectedHeader(li_SignatureIndex)
if loo_Jws2.LastMethodSuccess <> 1 then
    Write-Debug "No protected header found at the given index."
    destroy loo_JwsProtHdr
    destroy loo_Jws
    destroy loo_Jws2
    return
end if

loo_JoseHeader.EmitCompact = 0

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

// Output:

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


destroy loo_JwsProtHdr
destroy loo_Jws
destroy loo_Jws2