How to Use Security for .NET

The Security class in Aspose.Pdf.LowCode namespace provides a simplified API for encrypting and decrypting PDF documents in .NET applications.

Key Features

  1. Encrypt a PDF with a password and a permission set, using one of four directly-verified algorithms: RC4x40, RC4x128, AESx128, or AESx256.
  2. Control exactly what a password-protected reader can do, through DocumentPrivilege’s individual switches such as AllowPrint, AllowCopy, and AllowModifyContents.
  3. Decrypt a PDF using only the owner password, via DecryptionOptions.
  4. Process input and output as in-memory streams, using StreamDataSource, instead of writing temporary files to disk.

Use Cases

  • Restrict who can open a confidential PDF, by requiring a password to view it at all.
  • Allow a document to be opened and read while still blocking printing or copying, by combining a password with DocumentPrivilege’s individual switches such as AllowPrint and AllowCopy.
  • Remove password protection from a PDF you control, once it no longer needs to be restricted.

Setup and Licensing

Apply metered licensing before any conversion:

using Aspose.Pdf;

Metered metered = new Metered();
metered.SetMeteredKey("publicKey", "privateKey");

Articles

Security Encryption and Decryption Guide

Prerequisites

  • Aspose.PDF for .NET (version 26.10.0 or later)
  • Valid Aspose Metered API key

Basic Usage 

using Aspose.Pdf.LowCode;
using Aspose.Pdf.Facades;

var security = new Security();
var encryptOptions = new EncryptionOptions(
    "userPassword123", "ownerPassword456",
    DocumentPrivilege.ForbidAll, CryptoAlgorithm.AESx256);
encryptOptions.AddInput(new FileDataSource("input.pdf"));
encryptOptions.AddOutput(new FileDataSource("encrypted.pdf"));
security.Process(encryptOptions);

Advanced Usage with Options 

using Aspose.Pdf.LowCode;
using Aspose.Pdf.Facades;

var permissions = DocumentPrivilege.AllowAll;
permissions.AllowPrint = false;

var encryptOptions = new EncryptionOptions(
    "userPassword123", "ownerPassword456",
    permissions, CryptoAlgorithm.AESx256);
encryptOptions.AddInput(new FileDataSource("input.pdf"));
encryptOptions.AddOutput(new FileDataSource("encrypted.pdf"));

var security = new Security();
security.Process(encryptOptions);

See Also