PDFlib PLOP (PDF Linearization, Optimization, Protection) is a versatile tool for linearizing, optimizing, repairing, analyzing, encrypting and decrypting PDF documents.
The extended version PLOP DS (Digital Signature) supports all features of PLOP plus the ability to apply digital signatures to PDF documents.
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.
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 color profiles, etc.
PLOP can apply user and master passwords, and set permission restrictions to prevent the document from being printed with Acrobat, disallow text extraction or modification, etc.
PLOP supports strong AES-256 encryption and Unicode passwords. With PLOP you can:
PLOP also supports certificate security which works similar to e‑mail encryption. PDF documents can be encrypted for a number of recipients, where each recipient is identified with a certificate (public key). Only legitimate recipients can open the document with the corresponding digital ID (private key). Since certificate security is an integral part of the PDF format specification it works in Acrobat and Adobe Reader without the need for any plugin or other custom software.
Certificate security offers several advantages over password security:
With PLOP you can encrypt PDF documents with certificates, apply permission restrictions, and decrypt documents which are protected with certificate security (provided you have a suitable digital ID). The advantages of certificate security can be leveraged e.g. for securely distributing transaction documents or commercial content.
PLOP detects various structural PDF problems and automatically repairs the document. PLOP can also fix certain XMP problems and optionally remove damaged XMP metadata.
The PLOP library includes the pCOS programming interface for querying details about a PDF document, e.g.
PLOP also includes the pCOS command-line tool.
Metadata (»data about data«) is an important topic in many areas of application software. XMP (Extensible Metadata Platform) is an XML-based framework with many predefined metadata properties. XMP is integrated in Acrobat/PDF, and much more powerful than simple document info entries. XMP is required for PDF/A and other ISO standards. Many industry groups have published XMP-based recommendations for vertical applications.
With PLOP you can insert XMP metadata in PDF documents and extract XMP from PDF. Inserted XMP is validated to ensure correct and standard-conforming output. If the input document conforms to PDF/A or PDF/X, PLOP ensures the XMP rules set forth in the respective standard.
XMP insertion with PLOP can be used in the following and many other situations (sample XMP files are contained in the PLOP distribution):
With PLOP you can add new document information entries or replace the values of existing info entries. Both predefined and custom entries can be set. If the input document contains XMP document metadata, all predefined info entries are synchronized to the XMP metadata in order to keep the metadata consistent (this is a requirement of PDF/A).
PLOP supports all relevant PDF versions and standards:
PLOP is available as a programming library (component) for various development environments, and as a command-line tool for batch operations. Library and command-line tool offer similar features, but are suitable for different deployment tasks.
The PLOP programming library is used for integration into your desktop or server application. Examples for using the library with all supported language bindings are included in the PLOP package. Since the PLOP library accepts PDF input documents from a disk file or directly in memory, it can easily be combined with other products.
The PLOP command-line tool is suited for batch processing PDF documents. It doesn’t require any programming, but offers powerful command-line options which can be used to integrate it into complex workflows. The PLOP command-line tool can also be called from environments which do not support the use of the PLOP library.
PDFlib PLOP is everywhere – it runs on practically all computing platforms. We offer 32-bit and 64-bit packages for all common flavors of Windows, macOS, Linux and Unix, as well as for IBM zSeries mainframe systems. Versions for iOS and Android are also available.
The PLOP core is written in highly optimized C and C++ code for maximum performance and small overhead. Via a simple API (Application Programming Interface) the PLOP functionality is accessible from a variety of development environments:
The extended version PLOP DS supports all features of PLOP plus the ability to apply digital signatures to PDF documents. Please see the separate PLOP DS pages for more information.