Mac m;
        byte[] signingKey;
        switch ( dialect ) {
        case Smb2Constants.SMB2_DIALECT_0202:
        case Smb2Constants.SMB2_DIALECT_0210:
            m = Mac.getInstance("HmacSHA256");
            signingKey = sessionKey;
            break;
        case Smb2Constants.SMB2_DIALECT_0300:

                if ( r.getDialectRevision() == Smb2Constants.SMB2_DIALECT_ANY ) {
                    return negotiate2(r);
                }
                else if ( r.getDialectRevision() != Smb2Constants.SMB2_DIALECT_0202 ) {
                    throw new CIFSException("Server returned invalid dialect verison in multi protocol negotiation");
                }

                int permits = r.getInitialCredits();