Section:

Encrypt & Decrypt PDFs - Java Sample Code

Sample code for using Apryse SDK to read encrypted (password protected) documents, secure a document with encryption, or remove encryption. Samples provided in Python, C++, C#, Java, Node.js (JavaScript), PHP, Ruby, Go and VB. Learn more about our Server SDK.

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2024 by Apryse Software Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.
4//---------------------------------------------------------------------------------------
5
6import java.io.BufferedReader;
7import java.io.IOException;
8import java.io.InputStreamReader;
9
10import com.pdftron.common.PDFNetException;
11import com.pdftron.filters.FilterReader;
12import com.pdftron.filters.FlateEncode;
13import com.pdftron.filters.MappedFile;
14import com.pdftron.pdf.*;
15import com.pdftron.sdf.*;
16
17
18//---------------------------------------------------------------------------------------
19// This sample shows encryption support in PDFNet. The sample reads an encrypted document and 
20// sets a new SecurityHandler. The sample also illustrates how password protection can 
21// be removed from an existing PDF document.
22//---------------------------------------------------------------------------------------
23public class EncTest {
24    public static void main(String[] args) {
25        PDFNet.initialize(PDFTronLicense.Key());
26
27        // Relative path to the folder containing test files.
28        String input_path = "../../TestFiles/";
29        String output_path = "../../TestFiles/Output/";
30
31        // Example 1:
32        // secure a document with password protection and
33        // adjust permissions
34
35        // Open the test file
36        System.out.println("Securing an existing document ...");
37        try (PDFDoc doc = new PDFDoc((input_path + "fish.pdf"))) {
38            doc.initSecurityHandler();
39
40            // Perform some operation on the document. In this case we use low level SDF API
41            // to replace the content stream of the first page with contents of file 'my_stream.txt'
42            if (true)  // Optional
43            {
44                System.out.println("Replacing the content stream, use flate compression...");
45
46                // Get the page dictionary using the following path: trailer/Root/Pages/Kids/0
47                Obj page_dict = doc.getTrailer().get("Root").value()
48                        .get("Pages").value()
49                        .get("Kids").value()
50                        .getAt(0);
51
52                // Embed a custom stream (file mystream.txt) using Flate compression.
53                MappedFile embed_file = new MappedFile((input_path + "my_stream.txt"));
54                FilterReader mystm = new FilterReader(embed_file);
55                page_dict.put("Contents",
56                        doc.createIndirectStream(mystm,
57                                new FlateEncode(null)));
58            }
59
60            //encrypt the document
61
62            // Apply a new security handler with given security settings.
63            // In order to open saved PDF you will need a user password 'test'.
64            SecurityHandler new_handler = new SecurityHandler();
65
66            // Set a new password required to open a document
67            String user_password = "test";
68            new_handler.changeUserPassword(user_password);
69
70            // Set Permissions
71            new_handler.setPermission(SecurityHandler.e_print, true);
72            new_handler.setPermission(SecurityHandler.e_extract_content, false);
73
74            // Note: document takes the ownership of new_handler.
75            doc.setSecurityHandler(new_handler);
76
77            // Save the changes.
78            System.out.println("Saving modified file...");
79            doc.save((output_path + "secured.pdf"), SDFDoc.SaveMode.NO_FLAGS, null);
80        } catch (PDFNetException e) {
81            e.printStackTrace();
82        }
83
84        // Example 2:
85        // Opens the encrypted document and removes all of
86        // its security.
87        try (PDFDoc doc = new PDFDoc((output_path + "secured.pdf"))) {
88            //If the document is encrypted prompt for the password
89            if (!doc.initSecurityHandler()) {
90                boolean success = false;
91                System.out.println("The password is: test");
92                for (int count = 0; count < 3; count++) {
93                    BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
94                    System.out.println("A password required to open the document.");
95                    System.out.print("Please enter the password: ");
96                    String password = r.readLine();
97                    if (doc.initStdSecurityHandler(password)) {
98                        success = true;
99                        System.out.println("The password is correct.");
100                        break;
101                    } else if (count < 3) {
102                        System.out.println("The password is incorrect, please try again");
103                    }
104                }
105                if (!success) {
106                    System.out.println("Document authentication error....");
107                    PDFNet.terminate();
108                }
109            }
110
111            //remove all security on the document
112            doc.removeSecurity();
113            doc.save(output_path + "not_secured.pdf", SDFDoc.SaveMode.NO_FLAGS, null);
114        } catch (Exception e) {
115            e.printStackTrace();
116        }
117
118        // Example 3:
119        // Encrypt/Decrypt a PDF using PDFTron custom security handler
120        System.out.println("-------------------------------------------------");
121        System.out.println("Encrypt a document using PDFTron Custom Security handler with a custom id and password...");
122        try (PDFDoc doc = new PDFDoc(input_path + "BusinessCardTemplate.pdf"))
123        {   
124            // Create PDFTron custom security handler with a custom id. Replace this with your own integer
125            int custom_id = 123456789;
126            PDFTronCustomSecurityHandler custom_handler = new PDFTronCustomSecurityHandler(custom_id);
127
128            // Add a password to the custom security handler
129            String pass = "test";
130            custom_handler.changeUserPassword(pass);
131
132            // Save the encrypted document
133            doc.setSecurityHandler(custom_handler);
134            doc.save(output_path + "BusinessCardTemplate_enc.pdf", SDFDoc.SaveMode.NO_FLAGS, null);
135                    
136            System.out.println("Decrypt the PDFTron custom security encrypted document above...");
137            // Register the PDFTron Custom Security handler with the same custom id used in encryption
138            PDFNet.addPDFTronCustomHandler(custom_id);
139
140            PDFDoc doc_enc = new PDFDoc(output_path + "BusinessCardTemplate_enc.pdf");
141            doc_enc.initStdSecurityHandler(pass);
142            doc_enc.removeSecurity();
143            // Save the decrypted document
144            doc_enc.save(output_path + "BusinessCardTemplate_enc_dec.pdf", SDFDoc.SaveMode.NO_FLAGS, null);
145            System.out.println("Done. Result saved in BusinessCardTemplate_enc_dec.pdf");
146        } catch (Exception e) {
147            e.printStackTrace();
148        }
149        System.out.println("-------------------------------------------------");
150        System.out.println("Tests completed.");
151        PDFNet.terminate();
152    }
153}

Did you find this helpful?

Trial setup questions?

Ask experts on Discord

Need other help?

Contact Support

Pricing or product questions?

Contact Sales