Comparison: three methods for generating random strings in PHP

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 ASCII code range, the range is 33-126. you can adjust the range as needed. for example, the-English letter in the ASCII code table corresponds to a-z,

Method 1

1. Generate a random integer in 33-126, for example, 35.

2. convert 35 to corresponding ASCII characters, for example, 35 #.

3. Repeat steps 1 and 2 n and connect them to a n-bit 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 ASCII code range, here, the range is 33-126. you can adjust the range as needed. for example, 97-122 characters in the ASCII code table correspond to English letters a-z. for details, refer to the ASCII code table. chr (int $ ascii) the function is used to convert the corresponding integer $ ascii to the corresponding character.

 
 

  
  
Function create_password ($ pw_length =
  
  
{
  
  
$ Randpwd = ";
  
  
For ($ I = 0; $ I <$ pw_length; $ I ++)
  
  
{
  
  
$ Randpwd. = chr (mt_rand (33,126 ));
  
  
}
  
  
Return $ randpwd;
  
  
}
  
  
// Call this function to pass the length parameter $ pw_length = 6
  
  
Echo create_password (6 );
 
 

Method 2

1. preset a string $ chars, including A-z, a-Z, 0-9, and some special characters.

2. a random character in the $ chars string.

3. Repeat step 2 n times to obtain a password with a length of n.

 
 

  
  
Function generate_password ($ length = 8 ){
  
  
// Password character set, which can be any character you need
  
  
$ Chars = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789! @ # $ % ^ & * ()-_ [] {}<> ~ '+ = ,.;:/? | ';
  
  
$ Password = ";
  
  
For ($ I = 0; $ I <$ length; $ I ++)
  
  
{
  
  
// Two character acquisition methods are provided here
  
  
// Use substr to intercept any character in $ chars;
  
  
// The second method is to take any element of the character array $ 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. use array_rand () to randomly select $ length elements from the array $ chars.

3. extract the string from the array $ chars based on the obtained key name array $ keys. The disadvantage of this method is that the same characters are not repeated.

 
 

  
  
Function make_password ($ length = 8)
  
  
{
  
  
 
  
  
// Password character set, which can be any character 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 ′, '! ',
  
  
'@', '#', '$', '%', '^ ','&','*','(',')','-', '_',
  
  
'[', ']', '{', '}', '<', '> ','~ ', ''',' + ',' = ',',',
  
  
'.',';',':','/','? ',' | ');
  
  
 
  
  
// Random $ length array element key names in $ chars
  
  
$ Keys = ($ chars, $ length );
  
  
$ Password = ";
  
  
For ($ I = 0; $ I <$ length; $ I ++)
  
  
{
  
  
// Concatenate $ length array elements into strings
  
  
$ Password. = $ chars [$ keys [$ I];
  
  
}
  
  
Return $ password;
  
  
}
 
 

Time efficiency comparison

We use the following PHP code to calculate the running time of the above three random password generation functions to generate six passwords, and then compare their time efficiency. The final result is:

 
 

  
  
Method 1: 9.8943710327148E-5 seconds
  
  
Method 2: 9.6797943115234E-5 seconds
  
  
Method 3: 0.00017499923706055 seconds
 
 

We can see that method 1 and method 2 have almost the same execution time, while Method 3 has a longer running time.