MD5 encryption and validation of strings using Java

A few days ago, a Java proxy was used in Domino to write a simple function of encrypting and validating strings using MD5.

Reference articles:

1. Java encryption algorithm Implementation use case: Http://www-128.ibm.com/developerworks/cn/java/l-security

The implementation process is as follows:

1. Encrypt the password string:

First, the generation of a MessageDigest class: MessageDigest alg= messagedigest.getinstance ("MD5");

Add information to calculate the summary: Alg.update (Password.getbytes ()); Where password is the password string

Calculate the summary: byte[] Digest=alga.digest ();

Then convert the digest into 16: Byte2hex (Digest)

/*

* Binary conversion to hexadecimal string

*

* @param b-binary array @return hexadecimal string

*/

private static String Byte2hex (byte[] bytes) {

String hs = "";

String stmp = "";

for (int i = 0; i < bytes.length; i++) {

Stmp = (java.lang.Integer.toHexString (bytes[i] & 0XFF));

if (stmp.length () = = 1)

HS = HS + "0" + stmp;

Else

HS = HS + stmp;

}

return Hs.touppercase ();

Saves the generated 16 feed summary to the database.

2. Verification:

Gets the authentication password entered: password=doc.getitemvaluestring ("f_passwordvalidate");

Get the relevant summary in the database and convert the digest:

Byte[] Digest = tobytes (curdoc.getitemvaluestring ("F_password"));

/**

* Convert string to byte[]

* @param hex the string to be converted

* @return converted byte[]

*/

public static byte[] Tobytes (String hex) {

byte[] bytes = new BYTE[16];

for (int i = 0,j=0; I

BYTES[J] = integer.valueof (hex.substring (i,i+2), Bytevalue ();

}

return bytes;

}

Finally, verify that the comparison summary is the same:

result = Isvalidate (digest, password);

if (result = = True)

Retmsg = "Success". ";

Else

Retmsg = "failed." ";

public boolean isvalidate (byte[] Digest, String password) {

try {

MessageDigest alga = messagedigest.getinstance ("MD5");

Alga.update (Password.getbytes ());

if (Messagedigest.isequal (Digest, Alga.digest ()))

return true;

Else

return false;

catch (Exception ex) {

SYSTEM.OUT.PRINTLN ("algorithm error.");

return false;

}

}

Full Java code:

/*

* Created on 2005-9-23

*

*/

Package security;

Import Java.security.MessageDigest;

Import java.security.NoSuchAlgorithmException;

/**

* @author stunet

*

* MD5 encryption and validation examples using Java for strings

*

*/

public class Md5digestdemo {

public static void Main (string[] args) {

try {

Make string encryption

String password = "NET";

System.out.println ("Encrypted string:" + md5digestdemo.md5digest (password));

Perform string validation

String validate = md5digestdemo.md5digest (password);

String passwordvalidate = "NET";

Boolean issuccess = Md5digestdemo.isvalidate (tobytes (Validate),

Passwordvalidate);

if (issuccess)

SYSTEM.OUT.PRINTLN ("Validation successful!");

Else

System.out.println ("Validation failed!");

catch (NoSuchAlgorithmException e) {

E.printstacktrace ();

}

}

/**

*

* @param password

* Strings that need to be encrypted

* @return The encrypted string