Several ways to generate random passwords in PHP_PHP Tutorial

A random password is a string of fixed length. Here I have collected several methods of generating random strings for your reference.

Method 1:

1. Generate a random integer from 33 – 126, such as 35,
2. Convert 35 into the corresponding ASCII character, such as 35 corresponding to #
3. Repeat steps 1 and 2 above n times , concatenated into an n-digit password

This algorithm mainly uses two functions. The mt_rand (int $min, int $max) function is used to generate random integers, where $min – $max is the range of ASCII codes. Here, 33-126 is taken, which can be used as needed Adjustment range, for example, 97 – 122 bits in the ASCII code table correspond to the English letters a – z. For details, please refer to the ASCII code table; chr (int $ascii) function is used to convert the corresponding integer $ascii into the corresponding character.

Copy code The code is as follows:

function create_password($pw_length = 8)
{
$randpwd = '';
for ($i = 0; $i {
$randpwd .= chr(mt_rand(33, 126));
}
return $randpwd;
}

// Call this function, passing the length parameter $pw_length = 6
echo create_password(6);

method Two:
1. Preset a string $chars, including a – z, A – Z, 0 – 9, and some special characters
2. Randomly pick one from the $chars string Characters
3. Repeat the second step n times to get a password of length n

Copy code The code is as follows:

function generate_password( $length = 8 ) {
//Password character set, you can add any characters you need
$chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()-_ []{ }~`+=,.;:/?|';

$password = '';
for ( $i = 0; $i {
// There are two ways to obtain characters
// The first is to use substr to intercept any character in $chars;
// The second is to get the character array $ Any element of chars
// $password .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
$password .= $chars[ mt_rand(0, strlen( $chars) - 1) ];
}

return $password;
}

Method 3:

1. Preset a character array $chars, including a – z, A – Z, 0 – 9, and some special characters
2. Randomly select $length from the array $chars through array_rand() elements
3. According to the obtained key name array $keys, take out the characters from the array $chars and concatenate the string. The disadvantage of this method is that the same characters will not be retrieved repeatedly.

Copy code The code is as follows:

function make_password( $length = 8 )
{
// Password Character set, you can add any characters you need
$chars = array('a', 'b', 'c', 'd', 'e', ​​'f', 'g', 'h',
'i', 'j', 'k', 'l','m', 'n', 'o', 'p', 'q', 'r', 's',
't', 'u', 'v', 'w', 'x', 'y','z', 'A', 'B', 'C', 'D',
'E' , 'F', 'G', 'H', 'I', 'J', 'K', 'L','M', 'N', 'O',
'P', 'Q ', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y','Z',
'0', '1', ' 2', '3', '4', '5', '6', '7', '8', '9', '!',
'@','#', '$', '%', '^', '&', '*', '(', ')', '-', '_',
'[', ']', '{', '}' , '', '~', '`', '+', '=', ',',
'.', ';', ':', '/', '?', '|');

// Randomly select $length array element key names in $chars
$keys = array_rand($chars, $length);

$password = '';
for($i = 0; $i {
// Concatenate $length array elements into a string
$ password .= $chars[$keys[$i]];
}

return $password;
}

Method 4:
This method is a new method provided by a netizen after this article was reprinted by Blue Ideal. The algorithm is simple and the code is short. Just because of the return value of the md5() function, the generated password only includes letters and numbers. But it’s still a good method. Algorithm idea:
1. time() gets the current Unix timestamp
2. Encrypt the timestamp obtained in the first step with md5()
3. Intercept the result of the second step encryption and intercept n Get the password you want in just one click

Copy the code The code is as follows:

function get_password( $length = 8 )
{
$str = substr(md5(time()), 0, 6);
return $str;
}

Time efficiency comparison
We use the following PHP code to calculate the running time of the above 4 random password generation functions to generate a 6-digit password, and then conduct a simple comparison of their time efficiency.

Copy code The code is as follows:

function getmicrotime()
{
list($usec, $sec) = explode(" ",microtime());
return ((float)$usec + (float)$sec);
}

// record Start time
$time_start = getmicrotime();

// Put the PHP code to be executed here, such as:
// echo create_password(6);

// Record End time
$time_end = getmicrotime();
$time = $time_end - $time_start;

// Output the total running time
echo "execution time $time seconds";
?>

The final result is:
Method one: 9.8943710327148E-5 seconds
Method two: 9.6797943115234E-5 seconds
Method three: 0.00017499923706055 seconds
Method 4: 3.4093856811523E-5 seconds

It can be seen that the execution time of method 1 and method 2 are similar. Method 4 has the shortest running time, while method 3 has a slightly longer running time.

http://www.bkjia.com/PHPjc/322827.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/322827.htmlTechArticleA random password is a string of fixed length. Here I have collected several ways to generate random strings. method for your reference. Method 1: 1. Generate one in 33 – 126...