How to test the time required for crypt() encryption

M66 2025-05-27

In PHP, the crypt() function is often used to encrypt passwords. It supports a variety of algorithms, such as standard DES, MD5, SHA-256, SHA-512, etc. In security-related applications, it is very important to understand the execution time of the crypt() function, especially when evaluating system performance or performing password hashing cost control.

This article will introduce how to measure the encryption time of the crypt() function through PHP and give practical examples.

Measure time using microtime()

In PHP, you can use the microtime(true) function to obtain the current Unix timestamp (including microseconds), and measure the execution time of a certain piece of code by calculating the difference between the two timestamps before and after.

Here is an example of measuring the time-consuming encryption of crypt() function:

 <?php
$password = 'TestPassword123';
$salt = '$6$rounds=5000$usesomesillystringforsalt$'; // SHA-512 Example

$start = microtime(true);
$hash = crypt($password, $salt);
$end = microtime(true);

$duration = $end - $start;

echo "Encryption results: $hash\n";
echo "time consuming: " . number_format($duration, 6) . " Second\n";
?>

In the above example, we used the SHA-512 algorithm and set the encryption iterations to 5000 through the rounds parameter. You can observe the time-consuming changes under different encryption strengths by adjusting the rounds value.

Perform multiple tests with loops to get the average

To more accurately evaluate encryption time, crypt() can be performed multiple times and the average time is calculated:

 <?php
$password = 'TestPassword123';
$salt = '$6$rounds=5000$usesomesillystringforsalt$';
$iterations = 100;
$totalTime = 0;

for ($i = 0; $i < $iterations; $i++) {
    $start = microtime(true);
    crypt($password, $salt);
    $end = microtime(true);
    $totalTime += ($end - $start);
}

$averageTime = $totalTime / $iterations;

echo "平均加密time consuming（$iterations Second-rate）: " . number_format($averageTime, 6) . " Second\n";
?>

In this way, you can eliminate errors caused by occasional system fluctuations and more accurately evaluate encryption time.

Online demonstration and debugging

You can deploy these test scripts on your own server or use an online PHP execution environment. If you want to deploy on a test website, you can upload the script to a path such as https://www.m66.net/test/crypt_time.php to ensure that the server allows PHP scripts to be run in the CLI or web environment.

summary

crypt() is a powerful encryption tool provided by PHP, but it takes time to rely on the selected algorithm and the number of iterations. Through microsecond-level time measurement, we can reasonably evaluate the performance of its encryption process. This is crucial for system security and performance tuning. In practical applications, please reasonably select encryption parameters based on system capabilities and security needs to achieve a balance between security and performance.

crypt