(Lianja) 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 Lianja Extension Download Chilkat Lianja Extension

// 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
loJwsProtHdr = createobject("CkJsonObject")
loJwsProtHdr.AppendString("typ","JWT")
loJwsProtHdr.AppendString("alg","HS256")
? "JWS Protected Header: " + loJwsProtHdr.Emit()

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

loJws = createobject("CkJws")

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

// Set the protected header:
loJws.SetProtectedHeader(lnSignatureIndex,loJwsProtHdr)

// Set the payload.
llBIncludeBom = .F.
lcPayloadStr = "In our village, folks say God crumbles up the old moon into stars."
loJws.SetPayload(lcPayloadStr,"utf-8",llBIncludeBom)

// Create the JWS
// By default, the compact serialization is used.
lcJwsCompact = loJws.CreateJws()
if (loJws.LastMethodSuccess <> .T.) then
    ? loJws.LastErrorText
    release loJwsProtHdr
    release loJws
    return
endif

? "JWS: " + lcJwsCompact

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

// Now load the JWS, validate, and recover the original text.
loJws2 = createobject("CkJws")

// Load the JWS.
llSuccess = loJws2.LoadJws(lcJwsCompact)

// Set the MAC key used for validation.
lnSignatureIndex = 0
loJws2.SetMacKey(lnSignatureIndex,lcHmacKey,"base64url")

// Validate the 1st (and only) signature at index 0..
v = loJws2.Validate(lnSignatureIndex)
if (v < 0) then
    // Perhaps Chilkat was not unlocked or the trial expired..
    ? "Method call failed for some other reason."
    ? loJws2.LastErrorText
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

if (v = 0) then
    ? "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both."
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

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

// Recover the original content:
? loJws2.GetPayload("utf-8")

// Examine the protected header:
loJoseHeader = loJws2.GetProtectedHeader(lnSignatureIndex)
if (loJws2.LastMethodSuccess <> .T.) then
    ? "No protected header found at the given index."
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

loJoseHeader.EmitCompact = .F.

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

// Output:

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


release loJwsProtHdr
release loJws
release loJws2