(PHP ActiveX) Compress and Encrypt a Large File (Low and Constant Memory Footprint)

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Demonstrates how to compress and encrypt a large file such that the memory footprint remains low and constant.

Note: This example requires Chilkat v9.5.0.99 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

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

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Compression')
$compress = new COM("Chilkat.Compression");
$compress->Algorithm = 'deflate';

// Set encryption params.
// The possible values are the same as for the corresponding properties in the Chilkat Crypt2 class/object.
// The encoded IV and Key must be specified as hex.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.JsonObject')
$json = new COM("Chilkat.JsonObject");
$json->UpdateString('cryptAlgorithm','aes');
$json->UpdateString('cipherMode','cbc');
$json->UpdateInt('keyLength',128);
$json->UpdateInt('paddingScheme',0);
$json->UpdateString('encodedIV','000102030405060708090A0B0C0D0E0F');
$json->UpdateString('encodedKey','000102030405060708090A0B0C0D0E0F');

// Do file-to-file compression+encryption in a single call.
$inPath = 'qa_data/largeFile.dat';
$outPath = 'c:/temp/qa_output/compressed_encrypted.dat';
$success = $compress->CompressEncryptFile($json,$inPath,$outPath);
if ($success == 0) {
    print $compress->LastErrorText . "\n";
    exit;
}

// We can do file-to-file decrypt/decompress like this:
$inPath2 = $outPath;
$outPath2 = 'c:/temp/qa_output/restored.dat';
$success = $compress->DecryptDecompressFile($json,$inPath2,$outPath2);
if ($success == 0) {
    print $compress->LastErrorText . "\n";
    exit;
}

// Note: The above decrypt + decompress is the equivalent of doing the same in these two steps:
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Crypt2')
$crypt = new COM("Chilkat.Crypt2");
$crypt->CryptAlgorithm = 'aes';
$crypt->CipherMode = 'cbc';
$crypt->KeyLength = 128;
$crypt->PaddingScheme = 0;
$crypt->SetEncodedIV('000102030405060708090A0B0C0D0E0F','hex');
$crypt->SetEncodedKey('000102030405060708090A0B0C0D0E0F','hex');

$decryptedPath = 'c:/temp/qa_output/decrypted.dat';
$success = $crypt->CkDecryptFile($inPath2,$decryptedPath);
if ($success == 0) {
    print $crypt->LastErrorText . "\n";
    exit;
}

$outPath3 = 'c:/temp/qa_output/restored_in_two_steps.dat';
$success = $compress->DecompressFile($decryptedPath,$outPath3);
if ($success == 0) {
    print $compress->LastErrorText . "\n";
    exit;
}

print 'Success.' . "\n";

?>