我已经使用php，如下所示

<?php
$goodtext = "Not found";
// If there is no parameter, this code is all skipped
if ( isset($_GET['md5']) ) {
    $time_pre = microtime(true);
    $md5 = $_GET['md5'];
    // This is our alphabet
    $txt = "0123456789";
    $show = 15;
    // Outer loop go go through the alphabet for the
    // first position in our "possible" pre-hash
    // text
    for($i=0; $i<strlen($txt); $i++ ) {
        $ch1 = $txt[$i];   // The first of two characters
        // Our inner loop Note the use of new variables
        // $j and $ch2 
        for($j=0; $j<strlen($txt); $j++ ) {
            $ch2 = $txt[$j];  // Our second character
            for($k=0; $k<strlen($txt); $k++ ) {
                $ch3 = $txt[$k];
                for($l=0; $l<strlen($txt); $l++){
                    $ch4 = $txt[$l];
                    // Concatenate the two characters together to 
                    // form the "possible" pre-hash text
                    $try = $ch1.$ch2.$ch3.$ch4;
                    // Run the hash and then check to see if we match
                    $check = hash('md5', $try);
                    if ( $check == $md5 ) {
                        $goodtext = $try;
                        break;   // Exit the inner loop
                    }
                    // Debug output until $show hits 0
                    if ( $show > 0 ) {
                        print "$check $try\n";
                        $show = $show - 1;
                    }
                    if($goodtext == $try){
                        break;
                    }
                }
                if($goodtext == $try){
                    break;
                }
            }
            if($goodtext == $try) {
                break;  
            }
        }
        if($goodtext == $try){
            break;
        }
    }
    // Compute ellapsed time
    $time_post = microtime(true);
    print "Ellapsed time: ";
    print $time_post-$time_pre;
    print "\n";
}
?>

你可以参考这个资料来源

无论如何，我无意中发现了这一点，因为我想从一个将安装COM组件的程序的自然键合成guid;我希望进行综合，以免管理GUID生命周期。我将使用MD5，然后使用UUID类从中获取一个字符串。(http://stackoverflow.com/questions/2190890/how-can-i-generate-guid-for-a-string-values/12867439提出了这个问题)。

在任何情况下，java.util.UUID都可以从MD5字节中获得一个漂亮的String。

return UUID.nameUUIDFromBytes(md5Bytes).toString();

import java.security.MessageDigest

val digest = MessageDigest.getInstance("MD5")

//Quick MD5 of text
val text = "MD5 this text!"
val md5hash1 = digest.digest(text.getBytes).map("%02x".format(_)).mkString

//MD5 of text with updates
digest.update("MD5 ".getBytes())
digest.update("this ".getBytes())
digest.update("text!".getBytes())
val md5hash2 = digest.digest().map(0xFF & _).map("%02x".format(_)).mkString

//Output
println(md5hash1 + " should be the same as " + md5hash2)

如果你不需要最好的安全性，MD5是完全可以的，如果你正在做一些像检查文件完整性这样的事情，那么安全性就不是一个考虑因素。在这种情况下，您可能希望考虑一些更简单和更快的方法，例如Adler32, Java库也支持它。

你可以试试凯撒。

第一选择:

byte[] hash =
    new Hash(
        new ImmutableMessageDigest(
            MessageDigest.getInstance("MD5")
        ),
        new PlainText("String to hash...")
    ).asArray();

第二选择:

byte[] hash =
    new ImmutableMessageDigest(
        MessageDigest.getInstance("MD5")
    ).update(
        new PlainText("String to hash...")
    ).digest();

如果你真的想要返回一个字符串，而不是字节数组，你总是可以这样做:

String plaintext = "your text here";
MessageDigest m = MessageDigest.getInstance("MD5");
m.reset();
m.update(plaintext.getBytes());
byte[] digest = m.digest();
BigInteger bigInt = new BigInteger(1,digest);
String hashtext = bigInt.toString(16);
// Now we need to zero pad it if you actually want the full 32 chars.
while(hashtext.length() < 32 ){
  hashtext = "0"+hashtext;
}