Added AES-128 and RC4 up to 128 bits on PDFProtectionTrait

[erikn69]

the original author initiated this process: klemenv/FPDF_Protection/fpdf_protection.php,
but it hasn't been published; it seems to be working correctly.

// examples
$pdf->SetProtection(['print'], 'user123', 'admin123', 'AES', 128);
$pdf->SetProtection(['print'], 'user123', 'admin123', 'RC4', 40);
$pdf->SetProtection(['print'], 'user123', 'admin123', 'RC4', 128);

[alphp]

This Trait causes an invalid stream ending Exception in tests on GitHub Actions:

1) Fawno\FPDF\Tests\Scripts\PDFProtectionTraitTest::testPDFProtectionTrait
Exception: invalid stream ending
/app/vendor/ddn/sapp/src/PDFObjectParser.php:361
/app/vendor/ddn/sapp/src/PDFObjectParser.php:451
/app/vendor/ddn/sapp/src/PDFObjectParser.php:150
/app/vendor/ddn/sapp/src/PDFUtilFnc.php:559
/app/vendor/ddn/sapp/src/PDFUtilFnc.php:470
/app/vendor/ddn/sapp/src/PDFDoc.php:255
/app/vendor/ddn/sapp/src/PDFDoc.php:749
/app/vendor/ddn/sapp/src/PDFDoc.php:793
/app/vendor/ddn/sapp/src/PDFDoc.php:918
/app/tests/TestCase.php:51
/app/tests/TestCase.php:67
/app/tests/TestCase.php:60
/app/tests/Scripts/PDFProtectionTraitTest.php:24

This error predates this PR.

[erikn69]

Look at erikn69@f23fbd8
A simpler commit unrelated to this gives the same error;
I couldn't find the problem, but it only happens in github actions, on localhost:

root@e5a720beb1af:/var/www/github/FPDF-1# ./vendor/bin/phpunit
PHPUnit 12.5.24 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.0
Configuration: /var/www/github/FPDF-1/phpunit.xml

.....................                                             21 / 21 (100%)

Time: 00:01.042, Memory: 18.00 MB

OK (21 tests, 74 assertions)

Maybe
dealfonso/sapp/src/PDFDoc.php#L158-L160

[alphp]

Rebase, I marked affected tests as incomplete.

[erikn69]

Rebase, I marked affected tests as incomplete.

Revert 8c1dda9
The real problem: it's not validated whether the algorithm exists. RC-40 is unsafe and has been removed from current versions of OpenSSL. I did add a validation to ensure it uses fallback if the algorithm doesn't exist.

[alphp]

Revert 8c1dda9 The real problem: it's not validated whether the algorithm exists. RC-40 is unsafe and has been removed from current versions of OpenSSL. Add validation to ensure it uses fallback if the algorithm doesn't exist.

Now I understand why the tests don't fail on my systems. For work reasons, I have OpenSSL's legacy algorithms enabled.

[erikn69]

I have OpenSSL's legacy algorithms enabled.

Me too

[alphp]

I tried encryption using AES and it seems that something breaks.
File "example/test.php":

	// PDFProtection
	$pdf->SetProtection(['print'], 'user', 'admin', 'AES');

Result:
example.pdf

PS: It seems to be a problem with the viewer; I tested it with the built-in Chrome and Firefox viewers and the generated file displays correctly.