Abstract: In a networked computer environment, a client is unencumbered from signature generating components, yet conversant to transmit signature-based documents in a signature-based metalanguage such as XML. The nonsigning client/user invokes a signature from a signature server to send a payload of data in a signed message format to a recipient also conversant in the metalanguage, according to the metalanguage format. The nonsigning client receives a signature block including a signature value from the server. The client identifies a payload for transmission according to the metalanguage. Employing the metalanguage interpreter in client, the client stores the payload data in the signature block without disrupting the signature and the data it covers in the signature block. The nonsigning client the sends the resulting signature message including the payload data and the signature value, in the metalanguage format, to the recipient destination conversant in the metalanguage.