(Objective-C) Encrypt Already Existing Zip

To encrypt an already existing non-encrypted .zip, the application must open the .zip, set the encryption related properties, and then re-write.

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#import <CkoZip.h>

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

CkoZip *zip = [[CkoZip alloc] init];

// Open an unencrypted .zip
BOOL success = [zip OpenZip: @"qa_data/zips/test.zip"];
if (success != YES) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

// Unzip to a temp directory.
int numFilesUnzipped = [[zip Unzip: @"qa_output/tmp"] intValue];
if (numFilesUnzipped < 0) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

// Clear the zip object.
[zip NewZip: @"qa_output/aesTest.zip"];

// Indicate that 128-bit AES encryption is to be used when writing the .zip
zip.Encryption = [NSNumber numberWithInt:4];
zip.EncryptKeyLength = [NSNumber numberWithInt:128];

// Set the password.
zip.EncryptPassword = @"secret";

// Append the files.
zip.AppendFromDir = @"qa_output/tmp";
success = [zip AppendFiles: @"*.*" recurse: YES];
if (success != YES) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

// Write the .zip and close it.
success = [zip WriteZipAndClose];
if (success != YES) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

NSLog(@"%@",@"Success.");