Lianja 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. Lianja

llSuccess = .F.

//  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.

loJws = createobject("CkJws")

//  Set the HMAC key:
lcHmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
lnSignatureIndex = 0
loJws.SetMacKey(lnSignatureIndex,lcHmacKey,"base64url")

//  Load the JWS.
lcJwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
llSuccess = loJws.LoadJws(lcJwsCompact)

//  Validate the 1st (and only) signature at index 0..
v = loJws.Validate(lnSignatureIndex)
if (v < 0) then
    //  Perhaps Chilkat was not unlocked or the trial expired..
    ? "Method call failed for some other reason."
    ? loJws.LastErrorText
    release loJws
    return
endif

if (v = 0) then
    ? "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both."
    release loJws
    return
endif

//  If we get here, the signature was validated..
? "Signature validated."

//  Recover the original content:
? "Recovered content:"
? loJws.GetPayload("utf-8")

//  Examine the protected header:

loJoseHeader = createobject("CkJsonObject")
llSuccess = loJws.GetProtectedH(lnSignatureIndex,loJoseHeader)
if (llSuccess = .F.) then
    ? loJws.LastErrorText
    release loJws
    release loJoseHeader
    return
endif

loJoseHeader.EmitCompact = .F.

? "Protected (JOSE) header:"
? loJoseHeader.Emit()

//  Output:

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


release loJws
release loJoseHeader