Encryption

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2024 by Apryse Software Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.
4//---------------------------------------------------------------------------------------
5
6#import <OBJC/PDFNetOBJC.h>
7#import <Foundation/Foundation.h>
8
9//---------------------------------------------------------------------------------------
10// This sample shows encryption support in PDFNet. The sample reads an encrypted document and 
11// sets a new SecurityHandler. The sample also illustrates how password protection can 
12// be removed from an existing PDF document.
13//---------------------------------------------------------------------------------------
14int main(int argc, char *argv[])
15{
16    @autoreleasepool {
17        int ret = 0;
18        [PTPDFNet Initialize: 0];
19
20        // Example 1: 
21        // secure a PDF document with password protection and adjust permissions 
22        
23        @try
24        {
25            // Open the test file
26            NSLog(@"Securing an existing document ...");
27            PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/fish.pdf"];
28            [doc InitSecurityHandler];
29            
30            // Perform some operation on the document. In this case we use low level SDF API
31            // to replace the content stream of the first page with contents of file 'my_stream.txt'
32            if (NO)  // Optional
33            {
34                NSLog(@"Replacing the content stream, use Flate compression...");
35
36                // Get the page dictionary using the following path: trailer/Root/Pages/Kids/0
37                PTObj *page_dict = [[[[[[[[doc GetTrailer] Get: @"Root"] Value] Get: @"Pages"] Value ] Get: @"Kids"] Value] GetAt: 0];
38
39                // Embed a custom stream (file mystream.txt) using Flate compression.
40                PTMappedFile *embed_file = [[PTMappedFile alloc] initWithFilename: @"../../TestFiles/mystream.txt"];
41                PTFilterReader *mystm = [[PTFilterReader alloc] initWithFilter: embed_file];
42                PTFlateEncode *encode = [[PTFlateEncode alloc] initWithInput_filter: [[PTFilter alloc] init] compression_level: -1 buf_sz: 256];
43                [page_dict Put: @"Contents" obj: [doc CreateIndirectStream: mystm filter_chain: encode]];
44            }
45
46            //encrypt the document
47
48
49            // Apply a new security handler with given security settings. 
50            // In order to open saved PDF you will need a user password 'test'.
51            PTSecurityHandler *new_handler = [[PTSecurityHandler alloc] init];
52
53            // Set a new password required to open a document
54            NSString* user_password=@"test";
55            [new_handler ChangeUserPassword: user_password];
56
57            // Set Permissions
58            [new_handler SetPermission: e_ptprint value: YES];
59            [new_handler SetPermission: e_ptextract_content value: NO];
60
61            // Note: document takes the ownership of new_handler.
62            [doc SetSecurityHandler: new_handler];
63
64            // Save the changes.
65            NSLog(@"Saving modified file...");
66            [doc SaveToFile: @"../../TestFiles/Output/secured.pdf" flags: 0];
67
68        }
69        @catch(NSException *e)
70        {
71            NSLog(@"%@", e.reason);
72            ret = 1;
73        }
74
75        // Example 2:
76        // Opens an encrypted PDF document and removes its security.
77
78        @try
79        {
80            PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/Output/secured.pdf"];
81
82            //If the document is encrypted prompt for the password
83            if (![doc InitSecurityHandler]) 
84            {
85                bool success=NO;
86                NSLog(@"The password is: test");
87                int count;
88                for(count=0; count<3;count++)
89                {
90                    char input[255];
91                    NSLog(@"A password required to open the document.");
92                    NSLog(@"Please enter the password:");
93                    //scanf("%c", &input);
94                    NSString *password = @"test";
95    //                int i = 0;
96    //                for (; i < 254; i++) {
97    //                    if (input[i] == '\0') {
98    //                        break;
99    //                    }
100    //                    [password stringByAppendingFormat: @"%c", input[i]];
101    //                }
102                
103                    if([doc InitStdSecurityHandler: password])
104                    {
105                        success=true;
106                        NSLog(@"The password is correct.");
107                        break;
108                    }
109                    else if(count<3)
110                    {
111                        NSLog(@"The password is incorrect, please try again.");
112                    }
113                }
114                if(!success)
115                {
116                    NSLog(@"Document authentication error....");
117                    ret = 1;
118                    return ret;
119                }
120
121                PTSecurityHandler *hdlr = [doc GetSecurityHandler]; 
122                NSLog(@"Document Open Password: %d", [hdlr IsUserPasswordRequired]);
123                NSLog(@"Permissions Password: %d", [hdlr IsMasterPasswordRequired]);
124                NSLog(@"Permissions: ");
125                NSLog(@"    Has 'owner' permissions: %d", [hdlr GetPermission: e_ptowner]);
126                NSLog(@"    Open and decrypt the document: %d", [hdlr GetPermission: e_ptdoc_open]);
127                NSLog(@"    Allow content extraction: %d", [hdlr GetPermission: e_ptextract_content]); 
128                NSLog(@"    Allow full document editing: %d", [hdlr GetPermission: e_ptdoc_modify]);
129                NSLog(@"    Allow printing: %d", [hdlr GetPermission: e_ptprint]); 
130                NSLog(@"    Allow high resolution printing: %d", [hdlr GetPermission: e_ptprint_high]); 
131                NSLog(@"    Allow annotation editing: %d", [hdlr GetPermission: e_ptmod_annot]);
132                NSLog(@"    Allow form fill: %d", [hdlr GetPermission: e_ptfill_forms]);
133                NSLog(@"    Allow content extraction for accessibility: %d", [hdlr GetPermission: e_ptaccess_support]);
134                NSLog(@"    Allow document assembly: %d", [hdlr GetPermission: e_ptassemble_doc]);   
135            }
136
137            //remove all security on the document
138            [doc RemoveSecurity];
139            [doc SaveToFile: @"../../TestFiles/Output/not_secured.pdf" flags: 0];
140
141        }
142        @catch(NSException *e)
143        {
144            NSLog(@"%@", e.reason);
145            ret = 1;
146        }
147
148    // Example 3:
149    // Encrypt/Decrypt a PDF using PDFTron custom security handler
150
151        @try
152        {
153            NSLog(@"-------------------------------------------------");
154            NSLog(@"Encrypt a document using PDFTron Custom Security handler with a custom id and password...");
155            PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/BusinessCardTemplate.pdf"];
156
157            // Create PDFTron custom security handler with a custom id. Replace this with your own integer
158            unsigned int custom_id = 123456789;
159            PTSecurityHandler* custom_handler = [[PTPDFTronCustomSecurityHandler alloc] initWithCustom_id : custom_id];
160
161            // Add a password to the custom security handler
162            NSString *pass = @"test";
163            [custom_handler ChangeUserPassword: pass];
164
165            [doc SetSecurityHandler: custom_handler];
166
167            // Save the changes.
168            [doc SaveToFile: @"../../TestFiles/Output/BusinessCardTemplate_enc.pdf" flags: 0];
169
170
171            NSLog(@"Decrypt the PDFTron custom security encrypted document above...");
172            // Register the PDFTron Custom Security handler with the same custom id used in encryption
173            [PTPDFNet AddPDFTronCustomHandler : custom_id];
174            PTPDFDoc *doc_enc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/Output/BusinessCardTemplate_enc.pdf"];
175            [doc_enc InitStdSecurityHandler : pass];
176            [doc RemoveSecurity];
177            // Save the decrypted document
178            [doc SaveToFile: @"../../TestFiles/Output/BusinessCardTemplate_enc_dec.pdf" flags: 0];
179            NSLog(@"Done. Result saved in BusinessCardTemplate_enc_dec.pdf");
180
181        }
182        @catch(NSException *e)
183        {
184            NSLog(@"%@", e.reason);
185            ret = 1;
186        }
187        [PTPDFNet Terminate: 0];
188        return ret;
189    }
190}