Adobe Acrobat leverages PKCS#11 modules to interact with hardware tokens, such as Utimaco’s u.trust GP HSM Se-Series, to securely sign PDFs by providing a standard interface for Acrobat to access the token's private keys and perform cryptographic operations.
Adobe Acrobat uses a PKCS#11 module to encrypt a PDF by loading the module, which provides a secure interface to the certificate and its private key stored on a hardware token like SecurityServer. Acrobat then selects the appropriate digital ID (certificate) via the PKCS#11 interface to sign the document. This process establishes an encrypted digital signature, ensuring document authenticity and integrity, and allowing only intended recipients with the corresponding private key or certificate to decrypt the document.