(Objective-C) PDF Get Encryption and Permissions Information

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Determine if a PDF is encrypted, and the associated user permissions.

Note: Some PDFs are encrypted but not password-protected. In such cases, encryption is used primarily for preventing unauthorized modifications to the document, but it doesn't restrict access. Therefore, you can open and read the document without a password.

Note: This example requires Chilkat v9.5.0.96 or later.

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#import <CkoPdf.h>
#import <CkoJsonObject.h>
#import <NSString.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoPdf *pdf = [[CkoPdf alloc] init];

// Open a PDF.
// Starting in Chilkat v9.5.0.96, the LastJsonData will contain information about encryption and permissions.
BOOL success = [pdf LoadFile: @"c:/someDir/sample.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

// Examine the LastJsonData
CkoJsonObject *ljd = [pdf LastJsonData];
ljd.EmitCompact = NO;

NSLog(@"%@",[ljd Emit]);

// Sample output:

// {
//   "pdfVersion": "1.6",
//   "encrypt": {
//     "filter": "/Standard",
//     "keyLength": 128,
//     "V": 4,
//     "R": 4,
//     "P": -1340,
//     "perm": {
//       "printLowResolution": "allowed",
//       "printHighResolution": "allowed",
//       "modifyOther": "not allowed",
//       "modifyAnnotations": "allowed",
//       "modifyForms": "not allowed",
//       "fillInForms": "allowed",
//       "assembleDoc": "allowed",
//       "extractAnyPurpose": "not allowed",
//       "extractAccessibility": "not allowed"
//     },
//     "method": "AESV2"
//   }
// }

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

NSString *pdfVersion = [ljd StringOf: @"pdfVersion"];
NSString *Filter = [ljd StringOf: @"encrypt.filter"];
int KeyLength = [[ljd IntOf: @"encrypt.keyLength"] intValue];
int V = [[ljd IntOf: @"encrypt.V"] intValue];
int R = [[ljd IntOf: @"encrypt.R"] intValue];
int P = [[ljd IntOf: @"encrypt.P"] intValue];
NSString *PrintLowResolution = [ljd StringOf: @"encrypt.perm.printLowResolution"];
NSString *PrintHighResolution = [ljd StringOf: @"encrypt.perm.printHighResolution"];
NSString *ModifyOther = [ljd StringOf: @"encrypt.perm.modifyOther"];
NSString *ModifyAnnotations = [ljd StringOf: @"encrypt.perm.modifyAnnotations"];
NSString *ModifyForms = [ljd StringOf: @"encrypt.perm.modifyForms"];
NSString *FillInForms = [ljd StringOf: @"encrypt.perm.fillInForms"];
NSString *AssembleDoc = [ljd StringOf: @"encrypt.perm.assembleDoc"];
NSString *ExtractAnyPurpose = [ljd StringOf: @"encrypt.perm.extractAnyPurpose"];
NSString *ExtractAccessibility = [ljd StringOf: @"encrypt.perm.extractAccessibility"];
NSString *Method = [ljd StringOf: @"encrypt.method"];