| 摘要 |
We provide techniques for uniquely linking security elements in identificati on documents. In one implementation we provide a digital watermark embedded embedded on, and a smartcard (212) chip embedded in, an identification document. The smart card chip includes a hash or a reduced-bit representatio n of the digital watermark, while the digital watermark includes a hash of information stored on the smartcard chip. In another implementation we cross - correlate encryption keys carried by various machine-readable features (212a ) on an identification document. In still another implementation, we embed biometric information, which is stored in smartcard electronic circuitry, wi th a digital watermark. In one case the watermark is reversible, so that it can be removed to yield unmarked biometric information. In another case the watermark is fragile, to reveal whether the biometric information has been subjected to a transformation. In yet another implementation, we provide a jurisdictional indicator on an identification document. The jurisdictional indicator helps in decoding a digital watermark on the identification docume nt. |
