Xojo Plugin Requires Chilkat v11.0.0+

Validate JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

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

Dim success As Boolean
success = 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 a MAC key to validate and recover the protected header and payload.

Dim jws As New Chilkat.Jws

//  Set the HMAC key:
Dim hmacKey As String
hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
Dim signatureIndex As Int32
signatureIndex = 0
success = jws.SetMacKey(signatureIndex,hmacKey,"base64url")

//  Load the JWS.
Dim jwsCompact As String
jwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
success = jws.LoadJws(jwsCompact)

//  Validate the 1st (and only) signature at index 0..
Dim v As Int32
v = jws.Validate(signatureIndex)
If (v < 0) Then
    //  Perhaps Chilkat was not unlocked or the trial expired..
    System.DebugLog("Method call failed for some other reason.")
    System.DebugLog(jws.LastErrorText)
    Return
End If

If (v = 0) Then
    System.DebugLog("Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.")
    Return
End If

//  If we get here, the signature was validated..
System.DebugLog("Signature validated.")

//  Recover the original content:
System.DebugLog("Recovered content:")
System.DebugLog(jws.GetPayload("utf-8"))

//  Examine the protected header:

Dim joseHeader As New Chilkat.JsonObject
success = jws.GetProtectedH(signatureIndex,joseHeader)
If (success = False) Then
    System.DebugLog(jws.LastErrorText)
    Return
End If

joseHeader.EmitCompact = False

System.DebugLog("Protected (JOSE) header:")
System.DebugLog(joseHeader.Emit())

//  Output:

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