Encryption

CobaltPdf can password-protect the generated PDF using AES encryption (via PDFsharp). You can restrict individual operations such as printing, copying, and modification independently.

Basic Encryption

using static CobaltPdf.Configuration.PdfOptions;

var pdf = await renderer
    .WithEncryption(new PdfEncryptionOptions
    {
        UserPassword  = "open-me",     // password to open the document
        OwnerPassword = "admin-secret" // password to override permissions (optional)
    })
    .RenderUrlAsPdfAsync("https://example.com");

pdf.SaveAs("protected.pdf");

If OwnerPassword is omitted, CobaltPdf generates a cryptographically secure random owner password internally.

PdfEncryptionOptions Reference

Property	Type	Default	Description
UserPassword	string	required	Password required to open the document
OwnerPassword	string?	auto-generated	Password to override permission restrictions
AllowPrinting	bool	true	Permit the document to be printed
AllowCopying	bool	false	Permit text and content extraction
AllowModification	bool	false	Permit the document to be modified

Restricting All Permissions

var pdf = await renderer
    .WithEncryption(new PdfEncryptionOptions
    {
        UserPassword      = "view-only",
        AllowPrinting     = false,
        AllowCopying      = false,
        AllowModification = false
    })
    .RenderUrlAsPdfAsync("https://example.com/confidential");

Read-Only with Printing Allowed

var pdf = await renderer
    .WithEncryption(new PdfEncryptionOptions
    {
        UserPassword      = "print-ok",
        AllowPrinting     = true,   // printing allowed
        AllowCopying      = false,  // copy/paste blocked
        AllowModification = false
    })
    .RenderUrlAsPdfAsync("https://example.com/report");

Combining Encryption and Metadata

Encryption and metadata can be applied together. CobaltPdf runs both through PDFsharp in a single document pass:

var pdf = await renderer
    .WithMetadata(m =>
    {
        m.Title  = "Confidential Contract";
        m.Author = "Legal Department";
    })
    .WithEncryption(new PdfEncryptionOptions
    {
        UserPassword = "contract2025",
        AllowCopying = false
    })
    .RenderUrlAsPdfAsync("https://example.com/contract");

Tip

For embedding document properties such as title, author, and keywords, see the Metadata article.