$uuid = bin2hex(openssl_random_pseudo_bytes(16));
<?php
$str = "Shanghai";
echo "字符串:".$str."<br>";
echo "TRUE - 原始 20 字符二进制格式:".sha1($str, TRUE)."<br>";
echo "FALSE - 40 字符十六进制数:".sha1($str)."<br>";
?>
$uuid = bin2hex(openssl_random_pseudo_bytes(16));
<?php
$str = "Shanghai";
echo "字符串:".$str."<br>";
echo "TRUE - 原始 20 字符二进制格式:".sha1($str, TRUE)."<br>";
echo "FALSE - 40 字符十六进制数:".sha1($str)."<br>";
?>