PDFlib PLOP (PDFlib)

Repair, linearise, optimise, encrypt and decrypt PDF documents, plus apply digital signatures.


PDFlib PLOP (PDF Linearization, Optimization, Protection) is a versatile tool which can repair, linearize, optimize, encrypt, and decrypt PDF documents.

  • Linearization. With PDFlib PLOP you can linearize a PDF document for fast delivery over the Web (byteserving). Byteserving increases the perceived download speed since the first page is already visible while the remainder of the document is downloaded in the background.
  • Optimization. PLOP can significantly reduce the file size of a PDF document without affecting quality. It achieves this by removing unnecessary or redundant identical objects, such as repeatedly embedded fonts, images, identical ICC colour profiles, etc.
  • Repair Mode. Several kinds of damaged PDF documents are detected and automatically repaired, if possible.
  • Protection. PLOP can apply user and master passwords, and set access permissions to prevent the document from being printed with Acrobat, disallow text extraction or modification, etc. PLOP uses RC4 or AES encryption. AES encryption has been introduced in Acrobat 7, and is considered secure.

PDFlib PLOP DS (Digital Signature) offers all features of PLOP, plus the ability to apply digital signatures to PDF documents.

  • PLOP DS can apply standard PDF signatures which can be verified with Adobe Reader or Acrobat 6 and above. Signature support is available in the PLOP DS library and in the command-line tool, and works as follows:
  • PLOP DS reads certificates (digital IDs) from standard PKCS#12 or PFX files. On Windows, the certificate store can also be accessed to use certificates which are installed in the system.
  • PLOP DS can create signatures in existing signature fields or generate new fields to 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 and including PDF 1.7, the file format of Acrobat 8. Applying a signature can be combined with encryption (user password, master password, or permissions).

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Please contact us on +44 (0)20 8733 7103 or email sales@qbsd.co.uk