"Validation of an electronic signature requires data to validate the signature such as CA certificates, Certificate Revocation List (CRLs) or Certificate status information (OCSP) commonly provided by an online service (referred to in the present document as validation data). If the document is stored and the signatures are to be verifiable long after first created, in particular after the signing certificate has expired, the original validation data may no longer available or there may uncertainty as to what validation data was used when the document was first verified."
When writing a RadFixedPage containing widgets using the PdfPageStreamWriter.WriteContent() method an exception is thrown.
The exception: System.ArgumentNullException: 'Value cannot be null. Parameter name: context'
When importing a document with an invalid creation or modification date, an exception is thrown:
- FormatException: 'The input string '' was not in a correct format.'
- ArgumentOutOfRangeException: 'Year, Month, and Day parameters describe an unrepresentable DateTime.'
The hierarchical document structure is a means to describe the PDF document structure, which is currently not supported. See 10.6.1 Structure Hierarchy on 856 page of the PDF specification for details. This document structure is an alternative to the standard PDF structure and most non-Adobe software does not support it. The document might have been created with Adobe software like Adobe LiveCycle Designer. Very often the document contains some fallback text in the standard PDF structure like: "Please wait... If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document." "The document you are trying to load requires Adobe Reader 8 or higher. You may not have the Adobe Reader installed or your viewing environment may not be properly configured to use Adobe Reader. For information on how to install Adobe Reader and configure your viewing environment please see http://www.adobe.com/go/pdf_forms_configure." "For the best experience, open this PDF portfolio in Acrobat X, Reader X, or later."
PDF/A-1a is with conformance level A (for "accessibility"), and must adhere to all of the requirements of the PDF Reference as modified by the ISO 19005 specification. It requires structural and semantic properties to be preserved. Level 1a uses “Tagged PDF” and Unicode character maps to preserve the document's logical structure and content text stream in natural reading order. The following features are used: - Language specification - Hierarchical document structure - Tagged text spans and descriptive text for images and symbols - Character mappings to Unicode The purpose is to improve accessibility and make the content accessible for screen readers.
For complienace level PDF/A-2a please follow: PdfProcessing: Add support for PDF/A-2a compliance level.
The currently supported compliance levels can be found in the How to Comply with PDF/A Standard article.
Currently the DocumentInfo property is for export purposes only and meta information about documents is stripped when importing.
According to the PDF specification (ISO 32000), the document info dictionary (often called "metadata" or "Info" dictionary) can include the following standard fields:
• Title: The document’s title.
• Author: The name of the person who created the document.
• Subject: The subject of the document.
• Keywords: Keywords associated with the document.
• Creator: The application that created the original document.
• Producer: The application that converted the document to PDF.
• CreationDate: The date and time the document was created.
• ModDate: The date and time the document was last modified.
• Trapped: Indicates whether the document has been trapped (a printing term).
These fields are stored in the PDF’s Info dictionary and are used by PDF viewers for display, search, and indexing.
Purpose: Long-term archiving of electronic documents with full semantic structure.
- "A" for Archiving
Level "1a" ensures:
Tagged PDF (with proper logical structure and reading order)
Unicode text for proper text extraction and searchability
Embedded fonts (for consistent rendering)
Restrictions:
No audio/video
No encryption
No JavaScript
No external content (everything must be self-contained)
Based on: PDF 1.4 (Acrobat 5)