php 生成 N位随机数，并且加上MD5加密

function genToken( $len = 32, $md5 = true ) {

# Seed random number generator

# Only needed for PHP versions prior to 4.2

mt_srand( (double)microtime()*1000000 );

# Array of characters, adjust as desired

$chars = array(

'Q', '@', '8', 'y', '%', '^', '5', 'Z', '(', 'G', '_', 'O', '`',

'S', '-', 'N', '<', 'D', '{', '}', '[', ']', 'h', ';', 'W', '.',

'/', '|', ':', '1', 'E', 'L', '4', '&', '6', '7', '#', '9', 'a',

'A', 'b', 'B', '~', 'C', 'd', '>', 'e', '2', 'f', 'P', 'g', ')',

'?', 'H', 'i', 'X', 'U', 'J', 'k', 'r', 'l', '3', 't', 'M', 'n',

'=', 'o', '+', 'p', 'F', 'q', '!', 'K', 'R', 's', 'c', 'm', 'T',

'v', 'j', 'u', 'V', 'w', ',', 'x', 'I', '$', 'Y', 'z', '*'

);

# Array indice friendly number of chars;

$numChars = count($chars) - 1; $token = '';

# Create random token at the specified length

for ( $i=0; $i<$len; $i++ )

$token .= $chars[ mt_rand(0, $numChars) ];

# Should token be run through md5?

if ( $md5 ) {

# Number of 32 char chunks

$chunks = ceil( strlen($token) / 32 ); $md5token = '';

# Run each chunk through md5

for ( $i=1; $i<=$chunks; $i++ )

$md5token .= md5( substr($token, $i * 32 - 32, 32) );

# Trim the token

$token = substr($md5token, 0, $len);

} return $token;

}