Based on current understanding, a SIPRNet Public Key Infrastructure (PKI) token is designed for use specifically on the SIPRNet (Secret Internet Protocol Router Network) and is not intended for use on NIPRNet (Non- classified Internet Protocol Router Network) or public networks. In short: the token is intended for access to SIPRNet only, and cannot be used on NIPRNet or public networks. If you’re dealing with a training or test scenario, expect the official answer to reflect that SIPRNet PKI tokens are restricted to SIPRNet environments. [citation-style context from available public materials indicates this boundary, though exact official wording may vary by DoD policy documents]