Section:

Encryption

Sample Java code for using Apryse SDK to read encrypted (password protected) documents, secure a document with encryption, or remove encryption. Learn more about our Android SDK.

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.
4//---------------------------------------------------------------------------------------
5
6package com.pdftron.android.pdfnetsdksamples.samples;
7
8import com.pdftron.android.pdfnetsdksamples.OutputListener;
9import com.pdftron.android.pdfnetsdksamples.PDFNetSample;
10import com.pdftron.android.pdfnetsdksamples.R;
11import com.pdftron.android.pdfnetsdksamples.util.Utils;
12import com.pdftron.common.PDFNetException;
13import com.pdftron.filters.FilterReader;
14import com.pdftron.filters.FlateEncode;
15import com.pdftron.filters.MappedFile;
16import com.pdftron.pdf.PDFDoc;
17import com.pdftron.pdf.PDFNet;
18import com.pdftron.sdf.Obj;
19import com.pdftron.sdf.PDFTronCustomSecurityHandler;
20import com.pdftron.sdf.SDFDoc;
21import com.pdftron.sdf.SecurityHandler;
22
23import java.io.BufferedReader;
24import java.io.InputStreamReader;
25import java.util.ArrayList;
26
27public class EncTest extends PDFNetSample {
28
29	private static OutputListener mOutputListener;
30
31	private static ArrayList<String> mFileList = new ArrayList<>();
32
33    public EncTest() {
34        setTitle(R.string.sample_encryption_title);
35        setDescription(R.string.sample_encryption_description);
36    }
37
38	@Override
39	public void run(OutputListener outputListener) {
40		super.run(outputListener);
41		mOutputListener = outputListener;
42		mFileList.clear();
43		printHeader(outputListener);
44
45        // Example 1:
46        // secure a document with password protection and
47        // adjust permissions
48
49        // Open the test file
50        mOutputListener.println("Securing an existing document ...");
51        try (PDFDoc doc = new PDFDoc((Utils.getAssetTempFile(INPUT_PATH + "fish.pdf").getAbsolutePath()))) {
52            doc.initSecurityHandler();
53
54            // Perform some operation on the document. In this case we use low level SDF API
55            // to replace the content stream of the first page with contents of file 'my_stream.txt'
56            if (true)  // Optional
57            {
58                mOutputListener.println("Replacing the content stream, use flate compression...");
59
60                // Get the page dictionary using the following path: trailer/Root/Pages/Kids/0
61                Obj page_dict = doc.getTrailer().get("Root").value()
62                        .get("Pages").value()
63                        .get("Kids").value()
64                        .getAt(0);
65
66                // Embed a custom stream (file mystream.txt) using Flate compression.
67                MappedFile embed_file = new MappedFile((Utils.getAssetTempFile(INPUT_PATH + "my_stream.txt").getAbsolutePath()));
68                FilterReader mystm = new FilterReader(embed_file);
69                page_dict.put("Contents",
70                        doc.createIndirectStream(mystm,
71                                new FlateEncode(null)));
72            }
73
74            //encrypt the document
75
76            // Apply a new security handler with given security settings.
77            // In order to open saved PDF you will need a user password 'test'.
78            SecurityHandler new_handler = new SecurityHandler();
79
80            // Set a new password required to open a document
81            String user_password = "test";
82            new_handler.changeUserPassword(user_password);
83
84            // Set Permissions
85            new_handler.setPermission(SecurityHandler.e_print, true);
86            new_handler.setPermission(SecurityHandler.e_extract_content, false);
87
88            // Note: document takes the ownership of new_handler.
89            doc.setSecurityHandler(new_handler);
90
91            // Save the changes.
92            mOutputListener.println("Saving modified file...");
93            doc.save((Utils.createExternalFile("secured.pdf", mFileList).getAbsolutePath()), SDFDoc.SaveMode.NO_FLAGS, null);
94        } catch (PDFNetException e) {
95            mOutputListener.printError(e.getStackTrace());
96        }
97
98        // Example 2:
99        // Opens the encrypted document and removes all of
100        // its security.
101        try (PDFDoc doc = new PDFDoc((Utils.createExternalFile("secured.pdf", mFileList).getAbsolutePath()))) {
102            //If the document is encrypted prompt for the password
103            if (!doc.initSecurityHandler()) {
104                boolean success = false;
105                mOutputListener.println("The password is: test");
106                for (int count = 0; count < 3; count++) {
107                    BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
108                    mOutputListener.println("A password required to open the document.");
109                    mOutputListener.print("Please enter the password: ");
110                    // String password = r.readLine();
111                    if (doc.initStdSecurityHandler("test")) {
112                        success = true;
113                        mOutputListener.println("The password is correct.");
114                        break;
115                    } else if (count < 3) {
116                        mOutputListener.println("The password is incorrect, please try again");
117                    }
118                }
119                if (!success) {
120                    mOutputListener.println("Document authentication error....");
121                }
122            }
123
124            //remove all security on the document
125            doc.removeSecurity();
126            doc.save(Utils.createExternalFile("not_secured.pdf", mFileList).getAbsolutePath(), SDFDoc.SaveMode.NO_FLAGS, null);
127        } catch (Exception e) {
128            mOutputListener.printError(e.getStackTrace());
129        }
130
131        // Example 3:
132        // Encrypt/Decrypt a PDF using PDFTron custom security handler
133        mOutputListener.println("-------------------------------------------------");
134        mOutputListener.println("Encrypt a document using PDFTron Custom Security handler with a custom id and password...");
135        try (PDFDoc doc = new PDFDoc(Utils.getAssetTempFile(INPUT_PATH + "BusinessCardTemplate.pdf").getAbsolutePath()))
136        {   
137            // Create PDFTron custom security handler with a custom id. Replace this with your own integer
138            int custom_id = 123456789;
139            PDFTronCustomSecurityHandler custom_handler = new PDFTronCustomSecurityHandler(custom_id);
140
141            // Add a password to the custom security handler
142            String pass = "test";
143            custom_handler.changeUserPassword(pass);
144
145            // Save the encrypted document
146            doc.setSecurityHandler(custom_handler);
147            doc.save(Utils.createExternalFile("BusinessCardTemplate_enc.pdf", mFileList).getAbsolutePath(), SDFDoc.SaveMode.NO_FLAGS, null);
148                    
149            mOutputListener.println("Decrypt the PDFTron custom security encrypted document above...");
150            // Register the PDFTron Custom Security handler with the same custom id used in encryption
151            PDFNet.addPDFTronCustomHandler(custom_id);
152
153            PDFDoc doc_enc = new PDFDoc(Utils.createExternalFile("BusinessCardTemplate_enc.pdf", mFileList).getAbsolutePath());
154            doc_enc.initStdSecurityHandler(pass);
155            doc_enc.removeSecurity();
156            // Save the decrypted document
157            doc_enc.save(Utils.createExternalFile("BusinessCardTemplate_enc_dec.pdf", mFileList).getAbsolutePath(), SDFDoc.SaveMode.NO_FLAGS, null);
158            mOutputListener.println("Done. Result saved in BusinessCardTemplate_enc_dec.pdf");
159        } catch (Exception e) {
160            mOutputListener.printError(e.getStackTrace());
161        }
162        mOutputListener.println("-------------------------------------------------");
163        mOutputListener.println("Tests completed.");
164
165		for (String file : mFileList) {
166			addToFileList(file);
167		}
168		printFooter(outputListener);
169	}
170
171}

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