Objective-C Requires Chilkat v11.7.0+

Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4

See more PDF Protection Examples

Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it. Objective-C

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

BOOL success = NO;

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

//  The PDF used in this example is available at two_page_memo.pdf

CkoJsonObject *json = [[CkoJsonObject alloc] init];
CkoJsonObject *jsonOut = [[CkoJsonObject alloc] init];
CkoJsonObject *info = [[CkoJsonObject alloc] init];

//  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
CkoPdf *pdf1 = [[CkoPdf alloc] init];
success = [pdf1 LoadFile: @"qa_data/pdf/two_page_memo.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf1.LastErrorText);
    return;
}

pdf1.UserPassword = @"user-secret";
pdf1.OwnerPassword = @"owner-secret";
[json UpdateString: @"algorithmChoice" value: @"aes-256"];
success = [pdf1 Protection: @"encrypt" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@",pdf1.LastErrorText);
    return;
}

NSLog(@"%@%@%@%d",@"aes-256 will be saved as PDF ",[jsonOut StringOf: @"pending.pdfVersion"],@", Adobe extension level ",[[jsonOut IntOf: @"pending.adobeExtensionLevel"] intValue]);
success = [pdf1 WriteFile: @"qa_output/memo_aes256.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf1.LastErrorText);
    return;
}

success = [pdf1 PreLoadCheck: @"qa_output/memo_aes256.pdf" jsonOut: info];
if (success == NO) {
    NSLog(@"%@",pdf1.LastErrorText);
    return;
}

NSLog(@"%@%@%@%@",@"  saved file: ",[info StringOf: @"algorithm"],@", PDF ",[info StringOf: @"pdfVersion"]);

//  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
CkoPdf *pdf2 = [[CkoPdf alloc] init];
success = [pdf2 LoadFile: @"qa_data/pdf/two_page_memo.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf2.LastErrorText);
    return;
}

pdf2.UserPassword = @"user-secret";
pdf2.OwnerPassword = @"owner-secret";
[json UpdateString: @"algorithmChoice" value: @"aes-128"];
success = [pdf2 Protection: @"encrypt" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@",pdf2.LastErrorText);
    return;
}

NSLog(@"%@%@",@"aes-128 will be saved as PDF ",[jsonOut StringOf: @"pending.pdfVersion"]);
success = [pdf2 WriteFile: @"qa_output/memo_aes128.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf2.LastErrorText);
    return;
}

success = [pdf2 PreLoadCheck: @"qa_output/memo_aes128.pdf" jsonOut: info];
if (success == NO) {
    NSLog(@"%@",pdf2.LastErrorText);
    return;
}

NSLog(@"%@%@%@%@",@"  saved file: ",[info StringOf: @"algorithm"],@", PDF ",[info StringOf: @"pdfVersion"]);

//  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
CkoPdf *pdf3 = [[CkoPdf alloc] init];
success = [pdf3 LoadFile: @"qa_data/pdf/two_page_memo.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf3.LastErrorText);
    return;
}

pdf3.UserPassword = @"user-secret";
pdf3.OwnerPassword = @"owner-secret";
[json UpdateString: @"algorithmChoice" value: @"rc4-128"];
success = [pdf3 Protection: @"encrypt" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@",pdf3.LastErrorText);
    return;
}

NSLog(@"%@%@",@"rc4-128 will be saved as PDF ",[jsonOut StringOf: @"pending.pdfVersion"]);
success = [pdf3 WriteFile: @"qa_output/memo_rc4_128.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf3.LastErrorText);
    return;
}

success = [pdf3 PreLoadCheck: @"qa_output/memo_rc4_128.pdf" jsonOut: info];
if (success == NO) {
    NSLog(@"%@",pdf3.LastErrorText);
    return;
}

NSLog(@"%@%@%@%@",@"  saved file: ",[info StringOf: @"algorithm"],@", PDF ",[info StringOf: @"pdfVersion"]);

//  Sample output:

//  aes-256 will be saved as PDF 1.7, Adobe extension level 8
//    saved file: aes-256, PDF 1.7
//  aes-128 will be saved as PDF 1.6
//    saved file: aes-128, PDF 1.6
//  rc4-128 will be saved as PDF 1.4
//    saved file: rc4-128, PDF 1.4