Decrypt previously encrypted environment variables

decrypt.php

<?php

$secEnv = [];

function bootstrapSecEnv($key) {
    global $secEnv;
    foreach ($_SERVER as $name => $value) {
        if (is_string($value) && strpos($value, 'ENC:') === 0) {
            $secEnv[$name] = decryptEnv($key, substr($value, 4));
        }
    }
}

function secEnv($name, $fallback = '') {
    global $secEnv;
    if (isset($secEnv[$name])) {
        return $secEnv[$name];
    } elseif (isset($_SERVER[$name])) {
        return $_SERVER[$name];
    } else {
        return $fallback;
    }
}

function decryptEnv($key, $encoded) {
    list($iv, $value) = unserialize(base64_decode($encoded));
    return mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $value, MCRYPT_MODE_CBC, $iv);
}