Use of java.security.SecureRandom class
File 1: Passwordgenerator.java
import java.util.ArrayList;
import java.util.prefs.InvalidPreferencesFormatException;
import java.security.SecureRandom;
import java.text.ParseException;
public class Passwordgenerator {
private int length;
private boolean lowercaseIncluded;
private boolean numbersIncluded;
private boolean othersIncluded;
private boolean uppercaseIncluded;
private String password;
private String template;
static SecureRandom RANDOM = new SecureRandom();
Passwordgenerator() {
password = "";
template = "";
length = 8;
lowercaseIncluded = true;
uppercaseIncluded = true;
numbersIncluded = true;
othersIncluded = true;
generatePassword();
}
private boolean flagsOK() {
return lowercaseIncluded
|| uppercaseIncluded
|| numbersIncluded
|| othersIncluded;
}
private static char randomLowercase() {
char c =(char) (97 + (int) (RANDOM.nextDouble() * 26));
if(c=='l'){
return randomLowercase();
}
return c;
}
private static char randomUppercase() {
char c = (char) (65 + (int) (RANDOM.nextDouble() * 26));
if(c=='I'){
return randomUppercase();
}
return c;
}
private static char randomOther() {
char c =(char) (33 + (int) (RANDOM.nextDouble() * 15));
//if(c=='"'){
return '!';
//}
//return c;
}
/**
* @return a random character from '0' to '9'
*/
private static char randomNumber() {
return (char) (48 + (int) (RANDOM.nextDouble() * 10));
}
public void generatePassword() /* throws InvalidPreferencesFormatException, ParseException */ {
// clear password if necessary
if (password.length() != 0) {
password = "";
}
if (template.length() > 0) {
length = template.length();
for (int i = 0; i < length; i++) {
switch (template.charAt(i)) {
case 'a' :
password += randomLowercase();
break;
case 'A' :
password += randomUppercase();
break;
case 'n' :
case 'N' :
password += randomNumber();
break;
case 'o' :
case 'O' :
password += randomOther();
break;
}
}
} else {
ArrayList flags = new ArrayList();
if (lowercaseIncluded) {
flags.add(new randomLowercase());
}
if (uppercaseIncluded) {
flags.add(new randomUppercase());
}
if (othersIncluded) {
flags.add(new randomOther());
}
if (numbersIncluded) {
flags.add(new randomNumber());
}
int flagLength = flags.size();
for (int i = 0; i < length; i++) {
password += ((randomCharacter) flags.get( (int) (RANDOM.nextDouble() * flagLength) ))
.execute();
}
}
}
/**
* @return the length of the generated password
*/
public int getLength() {
return length;
}
/**
* @return the generated password
*/
public String getPassword() {
return password;
}
/**
* @return password template
*/
public String getTemplate() {
return template;
}
/**
* @return lowercaseIncluded
*/
public boolean isLowercaseIncluded() {
return lowercaseIncluded;
}
/**
* @return numbersIncluded
*/
public boolean isNumbersIncluded() {
return numbersIncluded;
}
/**
* @return othersIncluded
*/
public boolean isOthersIncluded() {
return othersIncluded;
}
/**
* @return uppercaseIncluded
*/
public boolean isUppercaseIncluded() {
return uppercaseIncluded;
}
/**
* @param length, enforced to be a positive integer >= 3.
*/
public void setLength(int length) {
this.length = (length < 3) ? 3 : length;
}
/**
* @param b
*/
public void setLowercaseIncluded(boolean b) throws InvalidPreferencesFormatException {
lowercaseIncluded = b;
// did we turn off the last flag? if so
// turn it back on and report error
if (b == false && !flagsOK()) {
lowercaseIncluded = true;
throw new InvalidPreferencesFormatException("At least one flag must be on to generate a password");
}
}
/**
* @param b
*/
public void setNumbersIncluded(boolean b) throws InvalidPreferencesFormatException {
numbersIncluded = b;
if (b == false && !flagsOK()) {
numbersIncluded = true;
throw new InvalidPreferencesFormatException("At least one flag must be on to generate a password");
}
}
/**
* @param b
*/
public void setOthersIncluded(boolean b) throws InvalidPreferencesFormatException {
othersIncluded = b;
// did we turn off the last flag? if so
// turn it back on and report error
if (b == false && !flagsOK()) {
othersIncluded = true;
throw new InvalidPreferencesFormatException("At least one flag must be on to generate a password");
}
}
/**
* @param string
*/
public void setTemplate(String template) throws ParseException {
// make sure the template contains only legal characters
for (int i = 0; i < template.length(); i++) {
switch (template.charAt(i)) {
case 'a' :
case 'A' :
case 'n' :
case 'N' :
case 'o' :
case 'O' :
break;
default :
throw new ParseException("Password template contains an invalid character", i);
}
}
this.template = template;
}
/**
* Clears the password template,making generation rely on the flags.
*
*/
public void clearTemplate() {
template = "";
}
/**
* @param b
*/
public void setUppercaseIncluded(boolean b) throws InvalidPreferencesFormatException {
uppercaseIncluded = b;
// did we turn off the last flag? if so
// turn it back on and report error
if (b == false && !flagsOK()) {
uppercaseIncluded = true;
throw new InvalidPreferencesFormatException("At least one flag must be on to generate a password");
}
}
/*--------------------------------------------------------
Wrapper classes and interface to mimic the array of
function references functionality required.
----------------------------------------------------------*/
private static class randomLowercase implements randomCharacter {
public char execute() {
return Passwordgenerator.randomLowercase();
}
}
private static class randomUppercase implements randomCharacter {
public char execute() {
return Passwordgenerator.randomUppercase();
}
}
private static class randomOther implements randomCharacter {
public char execute() {
return Passwordgenerator.randomOther();
}
}
private static class randomNumber implements randomCharacter {
public char execute() {
return Passwordgenerator.randomNumber();
}
}
private static interface randomCharacter {
char execute();
}
}
File 2: Test.java
import java.security.SecureRandom;
import java.text.ParseException;
import java.util.HashMap;
import java.util.Random;
public class Test {
/**
* @param args
*/
static String pwd;
public static void main(String[] args) {
String userName="mankar.m0(@gmail.com";
try {
boolean flag;
String[] templets =
{ "aaAnanaA", "aaannnAnaA", "aanAnnnaA", "aAAnnAaaA", "aaAnaaAA","aaAnnnaA", "aaananAnaA", "aanAnnnaa", "aAAanAaan", "aaAnaaAn" };
System.out.println("Uniq ID "+new java.security.SecureRandom().nextLong());
System.out.println("Uniq ID twwwwwo "+new java.util.Random().nextLong());
System.out.println("Math.random value of "+(Math.random()));
System.out.println("SecureRandom value of "+new java.security.SecureRandom().nextDouble());
Passwordgenerator passGen = new Passwordgenerator();
SecureRandom RANDOM = new SecureRandom();
//SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
//passGen.setTemplate(templets[sr.nextInt(20)]);
passGen.setTemplate(templets[(int)(RANDOM.nextDouble()*4)]);
do {
passGen.generatePassword();
pwd = passGen.getPassword();
flag = usernameCheck(userName, pwd);
//flag will be true is the password is not correct
} while (flag);
} catch (ParseException e) {
}catch(Exception e ){
}
System.out.println("Manish "+pwd.length()+" "+pwd);
Test t1 = new Test();
t1.generateId(10);
}
private static boolean usernameCheck(String uname, String pwd) {
return (
(pwd.toLowerCase()).matches(".*" + (uname.toLowerCase()) + ".*"));
}
protected String generateId( final int number )
{
Random rand = new Random( number );
//SecureRandom rand = new SecureRandom();
StringBuffer id = new StringBuffer();
String[] scrambled = new String[3];
StringBuffer nonrandom = scrambleNumber( number );
scrambled[0] = extractChar( scrambleNumber( rand.nextInt() ) );
scrambled[1] = extractChar( scrambleNumber( rand.nextInt() ) );
String first = nonrandom.substring( 0, 1 );
String rest = nonrandom.substring( 1 );
id.append( first );
id.append( scrambled[0] );
id.append( rest );
id.append( scrambled[1] );
System.out.println(id);
return id.toString();
}
protected String extractChar( StringBuffer random )
{
if ( random.length() > 3 ) {
return random.substring( 3, 4 );
}
return random.substring( 0, 1 );
}
/**
* <p>
*
* </p>
* @param number the number
* @return StringBuffer
*/
private StringBuffer scrambleNumber( final int number )
{
int abs = Math.abs( number );
int divisor = 27;
int mod = abs % divisor;
int div = abs / divisor;
if ( div == 0 ) {
return new StringBuffer( scrambleDigit( mod ) );
} else {
return scrambleNumber( div ).append( scrambleDigit( mod ) );
}
}
private String scrambleDigit( final int digit )
{
HashMap map = new HashMap();
map.put( "0", "D" );
map.put( "1", "N" );
map.put( "2", "C" );
map.put( "3", "K" );
map.put( "4", "A" );
map.put( "5", "M" );
map.put( "7", "G" );
map.put( "8", "X" );
map.put( "9", "L" );
map.put( "10", "H" );
map.put( "11", "W" );
map.put( "12", "4" );
map.put( "13", "Y" );
map.put( "14", "Q" );
map.put( "15", "5" );
map.put( "16", "J" );
map.put( "17", "3" );
map.put( "18", "E" );
map.put( "19", "8" );
map.put( "20", "V" );
map.put( "21", "6" );
map.put( "22", "T" );
map.put( "23", "P" );
map.put( "24", "B" );
map.put( "25", "9" );
map.put( "26", "F" );
String key = digit + "";
if(map.containsKey( key ))
{
return (String)map.get( key );
}
else
{
return "";
}
}
}
