Web, eCommerce, iOS, Android, Arduino and SEO

Encrypt or Decrypt Strings

Friday, March 15th, 2013 at 4:35 am

public class SimpleCrypto {

        public static String encrypt(String seed, String cleartext) throws Exception {
                byte[] rawKey = getRawKey(seed.getBytes());
                byte[] result = encrypt(rawKey, cleartext.getBytes());
                return toHex(result);
        }

        public static String decrypt(String seed, String encrypted) throws Exception {
                byte[] rawKey = getRawKey(seed.getBytes());
                byte[] enc = toByte(encrypted);
                byte[] result = decrypt(rawKey, enc);
                return new String(result);
        }

        private static byte[] getRawKey(byte[] seed) throws Exception {
                KeyGenerator kgen = KeyGenerator.getInstance("AES");
                SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
                sr.setSeed(seed);
            kgen.init(128, sr); // 192 and 256 bits may not be available
            SecretKey skey = kgen.generateKey();
            byte[] raw = skey.getEncoded();
            return raw;
        }

        private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
                Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
            byte[] encrypted = cipher.doFinal(clear);
                return encrypted;
        }

        private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
                Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] decrypted = cipher.doFinal(encrypted);
                return decrypted;
        }

        public static String toHex(String txt) {
                return toHex(txt.getBytes());
        }
        public static String fromHex(String hex) {
                return new String(toByte(hex));
        }

        public static byte[] toByte(String hexString) {
                int len = hexString.length()/2;
                byte[] result = new byte[len];
                for (int i = 0; i &lt; len; i++)
                        result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
                return result;
        }

        public static String toHex(byte[] buf) {
                if (buf == null)
                        return "";
                StringBuffer result = new StringBuffer(2*buf.length);
                for (int i = 0; i &lt; buf.length; i++) {
                        appendHex(result, buf[i]);
                }
                return result.toString();
        }
        private final static String HEX = "0123456789ABCDEF";
        private static void appendHex(StringBuffer sb, byte b) {
                sb.append(HEX.charAt((b&gt;&gt;4)&amp;0x0f)).append(HEX.charAt(b&amp;0x0f));
        }

}

public class SimpleCrypto {

public static String encrypt(String seed, String cleartext) throws Exception {

byte[] rawKey = getRawKey(seed.getBytes());

byte[] result = encrypt(rawKey, cleartext.getBytes());

return toHex(result);

}

public static String decrypt(String seed, String encrypted) throws Exception {

byte[] rawKey = getRawKey(seed.getBytes());

byte[] enc = toByte(encrypted);

byte[] result = decrypt(rawKey, enc);

return new String(result);

}

private static byte[] getRawKey(byte[] seed) throws Exception {

KeyGenerator kgen = KeyGenerator.getInstance("AES");

SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");

sr.setSeed(seed);

kgen.init(128, sr); // 192 and 256 bits may not be available

SecretKey skey = kgen.generateKey();

byte[] raw = skey.getEncoded();

return raw;

}

private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

byte[] encrypted = cipher.doFinal(clear);

return encrypted;

}

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.DECRYPT_MODE, skeySpec);

byte[] decrypted = cipher.doFinal(encrypted);

return decrypted;

}

public static String toHex(String txt) {

return toHex(txt.getBytes());

}

public static String fromHex(String hex) {

return new String(toByte(hex));

}

public static byte[] toByte(String hexString) {

int len = hexString.length()/2;

byte[] result = new byte[len];

for (int i = 0; i < len; i++)

result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();

return result;

}

public static String toHex(byte[] buf) {

if (buf == null)

return "";

StringBuffer result = new StringBuffer(2*buf.length);

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

appendHex(result, buf[i]);

}

return result.toString();

}

private final static String HEX = "0123456789ABCDEF";

private static void appendHex(StringBuffer sb, byte b) {

sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));

}

How to put one div in front of a other : HTML

Monday, March 11th, 2013 at 9:19 am

Leave your comment

<code>If you want to display the content of one div over another, you can use the following code :


&lt;html&gt;
    &lt;body&gt;
      &lt;style&gt;

       #div_1
       {
         position:absolute;
         left:0px;
         top:0px;
         z-index:-1;
       }
     &lt;/style&gt;

    &lt;div id='div_1'&gt;
       &lt;img src="https://www.google.co.in/images/srpr/logo3w.png" &gt; 
    &lt;/div&gt;

    &lt;div style="color:#0000FF"  id='div_2'&gt;
       &lt;p&gt;This is some text.&lt;/p&gt; 
    &lt;/div&gt;

    &lt;/body&gt;
  &lt;/html&gt;</code>

<code>If you want to display the content of one div over another, you can use the following code :

<html>

<body>

<style>

#div_1

{

position:absolute;

left:0px;

top:0px;

z-index:-1;

}

</style>

</div>

</div>

</body>

</html></code>

How to zoom in and zoom back to normal state : corona SDK

Monday, March 11th, 2013 at 9:16 am

Leave your comment

For this, just do as follows.

1: Create a scaleFactor:

local scale_factor = 0.2;

2: When you want to zoom out, do :

Your_object:scale(scale_factor,scale_factor)

3: When you want to zoom in, do :

Your_object:scale(1/scale_factor,1/scale_factor)

Getting the Child View Controllers of a View Controller in Xcode

Friday, March 8th, 2013 at 8:01 am

Leave your comment

We can get the child view controllers of a view controller using the childViewControllers property of the view controller.

If we are in a view controller class, if we want to get its child view controllers, then we can use the following code :

self.childViewControllers;

This will return an array of view controllers that are the child of the current view controller.

If there are no child view controllers of the current view controller, then the array will be empty.

If we are to get the child view controllers of a navigation controller, we can use the following code :

self.navigationController.childViewControllers;

Passing Multiple Parameters to PerformSelector Method in Xcode

Friday, March 8th, 2013 at 7:55 am

Leave your comment

It is possible to pass a single parameter to performSelector: method in Xcode using the following method :

[self performSelector:@selector(selectorNamewithArg:) withObject:param];

But what to do if we have to pass multiple parameters? There is a way to pass upto two parameters to the performSelector: method. It can be implemented using the following method :

[self performSelector:@selector(selectorNamewithArg1: Arg2:) withObject:param1 withObject:param2];

Here, two parameters are passed to the selector method.

LinkedHashMap example in Android

Wednesday, March 6th, 2013 at 6:38 pm

Leave your comment

//Initializing LinkedHashMap
LinkedHashMap&lt;Key, Value&gt; linkedHashMap = new LinkedHashMap&lt;Key, Value&gt;();

//add key and value
linkedHashMap.put(key, value);

//returns values
linkedHashMap.values();

//return value of given key
value = linkedHashMap.get(key);

//Initializing LinkedHashMap

LinkedHashMap<Key, Value> linkedHashMap = new LinkedHashMap<Key, Value>();

//add key and value

linkedHashMap.put(key, value);

//returns values

linkedHashMap.values();

//return value of given key

value = linkedHashMap.get(key);

How to selects one of three possible rendering modes for the physics engine: corona SDK

Tuesday, March 5th, 2013 at 11:08 am

Leave your comment

There are types of rendering modes in corona SDK physics engine. The rendering modes are very much useful for the developers. Here I’ll show you how to choose any of these 3 rendering modes.

Code:
physics.setDrawMode( "debug" ) -- It will show collision engine outlines only. physics.setDrawMode( "hybrid" ) -- It overlays collision outlines on normal Corona objects. physics.setDrawMode( "normal" ) -- It is the default Corona renderer, with no collision outlines.
(Note: You can change the mode at any time, if you want)

as simple as that…

Associate variable usage in Smarty

Monday, March 4th, 2013 at 6:22 pm

Leave your comment

You can create and assign associative array like following:

$smarty-&gt;assign(id,'name','age', 'job');
$smarty-&gt;assign('employee',array('id'=&gt;1, 'name'=&gt;'steve', 'age'=&gt;40, 'job'=&gt;'designer' ));

1 2	$smarty->assign(id,'name','age', 'job'); $smarty->assign('employee',array('id'=>1, 'name'=>'steve', 'age'=>40, 'job'=>'designer' ));

In the template page:

&lt;ul&gt;

&lt;li&gt;ID: {employee.id}&lt;/li&gt;

&lt;li&gt;Name: {employee.name}&lt;/li&gt;

&lt;li&gt;Age: {employee.age}&lt;/li&gt;

&lt;li&gt;Job: {employee.job}&lt;/li&gt;

&lt;/ul&gt;

<ul>

<li>ID: {employee.id}</li>

<li>Name: {employee.name}</li>

<li>Age: {employee.age}</li>

<li>Job: {employee.job}</li>

</ul>

To check if internet is available on android device

Monday, March 4th, 2013 at 11:34 am

Leave your comment

/*
* @return boolean return true if the application can access the internet
*/
private boolean haveInternet(){
        NetworkInfo info = ((ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
        if (info==null || !info.isConnected()) {
                return false;
        }
        if (info.isRoaming()) {
                // here is the roaming option you can change it if you want to disable internet while roaming, just return false
                return true;
        }
        return true;
}

* @return boolean return true if the application can access the internet

private boolean haveInternet(){

NetworkInfo info = ((ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

if (info==null || !info.isConnected()) {

return false;

}

if (info.isRoaming()) {

// here is the roaming option you can change it if you want to disable internet while roaming, just return false

return true;

}

return true;

}

To get the version of your application on the phone

Monday, March 4th, 2013 at 11:30 am

Leave your comment

public int getVersion(Context context) {
        try {
            PackageInfo pInfo = context.getPackageManager().getPackageInfo("here.thenameofyour.package", PackageManager.GET_META_DATA);
            return pInfo.versionCode;
        } catch (NameNotFoundException e) {
            return 0;
        }
    }
}

public int getVersion(Context context) {

try {

PackageInfo pInfo = context.getPackageManager().getPackageInfo("here.thenameofyour.package", PackageManager.GET_META_DATA);

return pInfo.versionCode;

} catch (NameNotFoundException e) {

return 0;

}

Page 8 of 320« First «...6 789 10...20 30 40...»Last »

SEO, SEM, Web, eCommerce, iOS and Android

Categories

Archives

Encrypt or Decrypt Strings

How to put one div in front of a other : HTML

How to zoom in and zoom back to normal state : corona SDK

Getting the Child View Controllers of a View Controller in Xcode

Passing Multiple Parameters to PerformSelector Method in Xcode

LinkedHashMap example in Android

How to selects one of three possible rendering modes for the physics engine: corona SDK

Associate variable usage in Smarty

To check if internet is available on android device

To get the version of your application on the phone

Blogroll

Pages

Top Commentators