PHP/Utility Function/sha1

Comparing the output of md5 to that of sha1

 
<?php
echo "Encrypting <b>testing</b> using md5: ".md5("testing");
echo "<br />";
echo "Encrypting <b>testing</b> using sha1: ".sha1("testing");
?>

Generating a Unique Identifier

 
<?php
function create_unique() {
    $data = $_SERVER["HTTP_USER_AGENT"] . $_SERVER["REMOTE_ADDR"] . time() . rand();
    return sha1($data);
}
$newhash = create_unique();
echo "<pre>{$newhash}</pre>";
?>

string sha1 ( string str [, bool raw_output] )

 
<?
    print sha1("hello") . "\n";
    print sha1("Hello") . "\n";
    print sha1("hello") . "\n";
    print sha1("This is a very, very, very, very, very, very, very long test");
?>