Today saw the release of PDF Signet 1.3, the latest version of Czech independent developer Vaclav Slavik's Mac OS X certificate-based digital signature tool.
The headline feature of the new version is the addition of support for smartcards and eTokens. This will enable users to securely sign PDF documents without having to extract their private key from secure hardware storage.
The software allows users to both apply and validate digital signatures, and is integrated with 1st-party Mac OS X technologies like Keychain, Services, Automator and AppleScript.
PDF Signet 1.3 requires OS X 10.7 or later, and is available exclusively through the Mac App Store.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.