Sign a JWS with an HMAC Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetMacKey, which sets the symmetric MAC key for a signature. The key bytes are supplied in a named encoding such as hex or base64.

IncludeFile "CkJws.pb"
IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    success.i = 0

    jws.i = CkJws::ckCreate()
    If jws.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Protected header specifying HMAC-SHA256.
    header.i = CkJsonObject::ckCreate()
    If header.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckUpdateString(header,"alg","HS256")
    success = CkJws::ckSetProtectedHeader(jws,0,header)
    If success = 0
        Debug CkJws::ckLastErrorText(jws)
        CkJws::ckDispose(jws)
        CkJsonObject::ckDispose(header)
        ProcedureReturn
    EndIf

    bIncludeBom.i = 0
    success = CkJws::ckSetPayload(jws,"This is the content to sign.","utf-8",bIncludeBom)
    If success = 0
        Debug CkJws::ckLastErrorText(jws)
        CkJws::ckDispose(jws)
        CkJsonObject::ckDispose(header)
        ProcedureReturn
    EndIf

    ;  Set the symmetric MAC key for signature 0.  The key bytes are provided in the named encoding (here
    ;  base64).  In production, obtain the key from a secure source rather than hard-coding it.
    base64Key.s = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
    success = CkJws::ckSetMacKey(jws,0,base64Key,"base64")
    If success = 0
        Debug CkJws::ckLastErrorText(jws)
        CkJws::ckDispose(jws)
        CkJsonObject::ckDispose(header)
        ProcedureReturn
    EndIf

    jwsCompact.s = CkJws::ckCreateJws(jws)
    If CkJws::ckLastMethodSuccess(jws) = 0
        Debug CkJws::ckLastErrorText(jws)
        CkJws::ckDispose(jws)
        CkJsonObject::ckDispose(header)
        ProcedureReturn
    EndIf

    Debug jwsCompact


    CkJws::ckDispose(jws)
    CkJsonObject::ckDispose(header)


    ProcedureReturn
EndProcedure