pdf_crypto

Pdf encryption library for dart / flutter

Generate an encrypted document

final pdf = Document();

// Declare the encryption options
pdf.document.encryption = PdfEncryptionAES(
  pdf.document,
  user: '1234', // The user password (can copy and print)
  owner: '5678', // The owner password (has all rights)
  accessFlags: <PdfAccessFlags>{
    PdfAccessFlags.Copy,
    PdfAccessFlags.Print,
  },
  level: PdfAESLevel.high,
);

pdf.addPage(
  Page(
    build: (Context context) {
      return Text('This text is encrypted using AES 256');
    },
  ),
);

final File file = File('encrypted.pdf');
await file.writeAsBytes(await pdf.save());

Generate a signed document

final pdf = Document();

// Convert the PEM private key to BER
final privateKey = PdfSign.pemPrivateKey(
  File('key0.pem').readAsStringSync(),
);

// Convert the PEM x509 certificate to BER
final certificate = PdfSign.pemCertificate(
  File('cert0.pem').readAsStringSync(),
);

// If the chain is made of multiple certificates and a CA,
// put the sign certificate first.
final chain = [certificate];

pdf.addPage(
  Page(
    build: (Context context) => Column(
      children: <Widget>[
        Text('Click on this signature for more info:'),
        Signature(
          name: 'Signature',
          value: PdfSign.rsaSha1(
            privateKey: privateKey,
            certificates: chain,
          ),
          child: PdfLogo(),
        ),
      ],
    ),
  ),
);

final File file = File('signed.pdf');
await file.writeAsBytes(await pdf.save());

Generate a self-signed certificate

Generate a 2048 bits RSA key pair using OpenSSL

openssl genpkey -outform PEM -algorithm rsa -pkeyopt rsa_keygen_bits:2048 -out key.pem

Generate a self-signed certificate using OpenSSL for tests

openssl req -new -x509 -days 365 -key key.pem -out cert.pem -subj "/CN=John Doe"

Load an existing document for updating

It’s also possible to include a signature to the existing document.

// Load the existing document from disk (can be from network or anything else)
final template = File('template.pdf').readAsBytesSync();

// Import the original document and draw something on the first page
final pdf = Document.load(
  PdfDocumentParser(template),
);

// Update the first page
pdf.editPage(
  0, // index 0 for the first page
  Page(
    build: (context) => Center(
      child: Text('Hello World!'),
    ),
  ),
);

// Save the document to a new file
final file = File('updated.pdf');
await file.writeAsBytes(await pdf.save());

Merge multiple documents

final tools = PdfTools();

final parsed1 = PdfDocumentParser(await File('doc1.pdf').readAsBytes());
tools.addPages(parsed1);

final parsed2 = PdfDocumentParser(await File('doc2.pdf').readAsBytes());
tools.addPages(parsed2, [0, 2]); // only pages 0 and 2

final result = tools.save();

final file = File('merged.pdf');
await file.writeAsBytes(result);

Buy now

The premium version of the PDF package for Flutter is updated with the main package, to keep compatibility, and includes:

Document encryption¹ with AES 256 and other algorithms.
Existing PDF modification, for adding pages, and updating existing pages.
Digital signature, including signing existing documents.
Existing PDF digital signature validation.

For this, you get a perpetual license for any number of applications and developers, but not the right to share or sell the source code.

The process is not automated, so if you buy while I’m not available, you’ll not get the information from me in the minute. Usually you’ll get it within 6 hours.

Use this package as a library

Depend on it

Add this to your package’s pubspec.yaml file, replace PASSWORD with your credentials for this library:

dependencies:
  pdf_crypto:
    hosted:
      name: pdf_crypto
      url: https://pub.nfet.net/PASSWORD
    version: ^3.3.5

Install it

You can install packages from the command line:

with Flutter:
```
$ flutter pub get
```
Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:pdf_crypto/pdf_crypto.dart';

Changelog

3.3.4

Add Document Appender
Add form field parser
Add pre and post content streams for protected contents

3.3.3

Fix merging PDF with missing objects

3.3.2

Implement tools to merge multiple PDF

3.3.1

Fix loading a document with obj not on end of line

3.3.0

Improve Signature range offset
Add Compatibility with dart_pdf 3.10.0
Force some objects to be direct
Reuse the same objects for Pages and Catalog

3.2.9

Fix crossref parsing issue

3.2.8

Fix utf8 decoding issue

3.2.7

Fix loading ZLib compressed data on web

3.2.6

Implement ASCIIHex and LZW filters decoding
Fix issue reading some PDF documents

3.2.5

Add document parsing API

3.2.4

Implement PdfPageLabels loading
Fix some lint issues
Correctly parse nested MediaBox

3.2.3

Fix parsing files with mixed new-lines
Fix parsing pages with no /Resources
Fix object parsing with mixed new-lines
Implement Compressed objects parser
Add support for DecodeParms

3.2.2

Fix parsing of some document

3.2.1

Remove debug log

3.2.0

Update dependencies

3.1.0

Allow inplace page edit
Remove useless override
Add PdfDictStream parser
Add ASCII85 Decoder
Add Compressed XREF parser
Add Timestamp support
Add Pdf Document signature verification
Use public pkcs7 package

3.0.2

Add an option to save the graphic context
Fix x509 serial number again
Fix Issuer copy

3.0.1

Add missing export for the cert library
Remove duplicate certificate
Fix x509 serial number

3.0.0

Implement null-safety
Add Full support for PKCS#7 signatures

2.0.1

Update dependencies

2.0.0

Add a PDF parser
Add signature permissions
Add support for sha384 and sha512 signature digests
Add support for PKCS#7 signatures

1.0.5

Migrate to Pdf 1.13.0
Don’t use library style anymore
Remove asn1lib dependency

1.0.4

Update dependencies
Update analysis options

1.0.3

Add more public api documentation

1.0.2

Add examples and update the README

1.0.1

Fixes for pdf 1.6.0

1.0.0

Initial version

Documentation

API reference

Only for new documents created from code.↩︎