Php openSLL Encryption - to prevent special characters

Question

I want to create and encryption for get variabile passed in url and for asynchronous call

for example:

$textToEncrypt = "Hello World";
$encryptionMethod = "AES-256-CBC";
$secretHash = "cVb67YtfAz328oOikl96vBn";
$iv = "adfrf54dmnlo09ax";
$encryptedText = openssl_encrypt($textToEncrypt,$encryptionMethod,$secretHash, 0, $iv);

result is: W2p0S2qlSierJnIcA/AM3g==

there are some special characters, == always at the end. I want to prevent this! How can I output only 0-9 and A-Z and a-z characters?

thanks

Possible duplicate of [Passing base64 encoded strings in URL](http://stackoverflow.com/questions/1374753/passing-base64-encoded-strings-in-url) — Alex K., Oct 18 '16 at 14:12
Use Base58 or Base32 or Base16 or even Base2. I wouldn't go as far as suggesting Base1, because that's only for theoretical scholars. — Artjom B., Oct 18 '16 at 19:37

score 4 · Answer 1 · edited Mar 24 '18 at 12:25

4

I had the same issue. I wanted to remove the special characters. So, this is what I did. Convert the encrypted text into hex value using base64_encode($encryptedText). So, there will be no special characters. Then for the revert, use base64_decode before passing to openssl_decrypt.

edited Mar 24 '18 at 12:25

Dmitriy

5,525
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answered Mar 24 '18 at 12:05

hafij

208
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1

Please consider editing your answer to include a code example of your proposed solution. The [Markdown Editing Help](https://stackoverflow.com/editing-help) page may be useful for formatting your answer correctly. – Benji Mar 24 '18 at 12:28

score 1 · Answer 2 · answered May 09 '22 at 16:16

1

$ciphering = "AES-128-CTR";

use this as your cipher string, it'll remove any type of == from the end

answered May 09 '22 at 16:16

S Ahmad Saagar

11
1

SwiftNinjaPro · Answer 3 · 2019-05-21T16:36:26.140

I notice I had exactly 2 equal signs at the end of my encrypted string too. It seems theres always 2 equal signs at the end. Here's my solution

function encryptString($string, $action, $baseIP = 'false', $extraKey = ''){
    global $flag;

    $encryptedIP = '';

    if($baseIP){
        $encryptedIP = encryptString($_SERVER['REMOTE_ADDR'], 'encrypt', false);
    }

    $output = false;

    $encrypt_method = "AES-256-CBC";
    $secret_key = $flag['2nd-encrypt-key'].$encryptedIP.'-'.$extraKey;
    $secret_iv = $flag['2nd-encrypt-secret'].$encryptedIP.'-'.$extraKey;

    $key = hash('sha256', $secret_key);
    $iv = substr(hash('sha256', $secret_iv), 0, 16);

    $output;

    if($action == 'encrypt'){
        $output = openssl_encrypt($string, $encrypt_method, $key, 0, $iv);
        $output = base64_encode($output);
        //replace equal signs with char that hopefully won't show up
        $output = str_replace('=', '[equal]', $output);
    }else if($action == 'decrypt'){
        //put back equal signs where your custom var is
        $setString = str_replace('[equal]', '=', $string);
        $output = openssl_decrypt(base64_decode($setString), $encrypt_method, $key, 0, $iv);
    }

    return $output;
}

Php openSLL Encryption - to prevent special characters

3 Answers3