PHP's bcrypt ...

a.php

    <?php
     
    $options = ['salt' => "m7z6odpn/jenmx0ablkhge"];
     
    // PHP's bcrypt implementation ignores input after binary-zero. So ...
     
    echo password_hash("a\0",             PASSWORD_DEFAULT, $options) . "\n";
    echo password_hash("a\0bcd",          PASSWORD_DEFAULT, $options) . "\n";
    echo password_hash("a\0bcdasdasdads", PASSWORD_DEFAULT, $options) . "\n";
    echo password_hash("a\0aaa",          PASSWORD_DEFAULT, $options) . "\n";
     
    // ... return the same hash!

    // see http://blog.ircmaxell.com/2015/03/security-issue-combining-bcrypt-with.html

?>

b.txt

$2y$10$m7z6odpn/jenmx0ablkhge07wnzTKOYEH4K5r.ZrRyWNtQw31XUp6
$2y$10$m7z6odpn/jenmx0ablkhge07wnzTKOYEH4K5r.ZrRyWNtQw31XUp6
$2y$10$m7z6odpn/jenmx0ablkhge07wnzTKOYEH4K5r.ZrRyWNtQw31XUp6
$2y$10$m7z6odpn/jenmx0ablkhge07wnzTKOYEH4K5r.ZrRyWNtQw31XUp6