I took information from a series of posts and some prior knowledge to implement the following hashing algorithm. However there is a lot of talk about what implementations are secure and not secure. How does my method measure up? Is it secure?

public static function sha512($token,$cost = 50000,$salt = null) {
        $salt = ($salt == null) ? (generateToken(32)) : ($salt);
        $salt = '$6$rounds=' . $cost . '$' . $salt . ' $';
        return crypt($token, $salt);
}

public static function sha512Equals($token,$hash) {
    return (crypt($token,$hash) == $hash);
}


public static function generateToken($length,$characterPool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ') {
    $token = '';
    $max = mb_strlen($characterPool);
    
    for ($i = 0;$i < $length;$i++){
        $token .= $characterPool[cryptorand(0,$max)];
    }

    return $token;
}

public static function cryptorand($min, $max) {
    $range = $max - $min;
    
    if ($range < 0) 
        return $min;
 
    $log = log($range, 2);
    $bytes = (int) ($log / 8) + 1; // length in bytes
    $bits = (int) $log + 1; // length in bits
    $filter = (int) (1 << $bits) - 1; // set all lower bits to 1

    do {
        $rnd = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes)));
        $rnd = $rnd & $filter; // discard irrelevant bits
    } while ($rnd >= $range);

    return $min + $rnd;
}

So is this method secure? Are there more secure methods in PHP for hashing tokens and matching with tokens later on? Any criticism is hugely appreciated.

I took information from a series of posts and some prior knowledge to implement the following hashing algorithm.

However, there is a lot of talk about what implementations are secure and not secure. How does my method measure up? Is it secure? Are there more secure methods in PHP for hashing tokens and matching with tokens later on?

public static function sha512($token,$cost = 50000,$salt = null) {
        $salt = ($salt == null) ? (generateToken(32)) : ($salt);
        $salt = '$6$rounds=' . $cost . '$' . $salt . ' $';
        return crypt($token, $salt);
}

public static function sha512Equals($token,$hash) {
    return (crypt($token,$hash) == $hash);
}


public static function generateToken($length,$characterPool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ') {
    $token = '';
    $max = mb_strlen($characterPool);
    
    for ($i = 0;$i < $length;$i++){
        $token .= $characterPool[cryptorand(0,$max)];
    }

    return $token;
}

public static function cryptorand($min, $max) {
    $range = $max - $min;
    
    if ($range < 0) 
        return $min;
 
    $log = log($range, 2);
    $bytes = (int) ($log / 8) + 1; // length in bytes
    $bits = (int) $log + 1; // length in bits
    $filter = (int) (1 << $bits) - 1; // set all lower bits to 1

    do {
        $rnd = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes)));
        $rnd = $rnd & $filter; // discard irrelevant bits
    } while ($rnd >= $range);

    return $min + $rnd;
}