PLOP DS (Digital Signature) is based on PDFlib PLOP, a versatile tool for linearizing, optimizing, repairing, analyzing, encrypting and decrypting PDF documents. The extended version PLOP DS additionally offers the ability to apply digital signatures to PDF documents. The PDF signatures can be validated with Adobe Acrobat and Adobe Reader, without the need for any additional validation software

PDFlib PLOP DS applies standard PDF signatures which can be validated with Adobe Reader or Acrobat. Signature support in PLOP DS works as follows:

PLOP DS reads the signer’s digital ID (i.e. the certificate plus corresponding private key) from memory, a disk file, or a secure hardware token. The digital ID is used to generate a cryptographic signature for the PDF document.

PLOP DS can create signatures in existing signature fields or generate new fields which hold the signature. The generated signatures can be invisible, or visible at a particular location on the page. Several signature properties which will be displayed in Acrobat can be specified, such as the reason of the signature, location, contact info, etc.

PLOP DS supports all PDF versions up to Acrobat 9. Applying a signature can be combined with encryption (user password, master password, or permissions).

PLOP uses the SHA-1 hash algorithm for generating the signatures and supports the RSA and DSA signature algorithms with a key length of up to 4096 bit.

More...