AES Encrypt String in VB.NET

This is example code for AES Encrypted String:

Public Function AES_Encrypt(ByVal input As String, ByVal pass As String) As String
        Dim AES As New System.Security.Cryptography.RijndaelManaged
        Dim Hash_AES As New System.Security.Cryptography.MD5CryptoServiceProvider
        Dim encrypted As String = ""
        Try
            Dim hash(31) As Byte
            Dim temp As Byte() = Hash_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass))
            Array.Copy(temp, 0, hash, 0, 16)
            Array.Copy(temp, 0, hash, 15, 16)
            AES.Key = hash
            AES.Mode = Security.Cryptography.CipherMode.ECB
            Dim DESEncrypter As System.Security.Cryptography.ICryptoTransform = AES.CreateEncryptor
            Dim Buffer As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(input)
            encrypted = Convert.ToBase64String(DESEncrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
            Return encrypted
        Catch ex As Exception
        End Try
    End Function

Public Function AES_Decrypt(ByVal input As String, ByVal pass As String) As String
        Dim AES As New System.Security.Cryptography.RijndaelManaged
        Dim Hash_AES As New System.Security.Cryptography.MD5CryptoServiceProvider
        Dim decrypted As String = ""
        Try
            Dim hash(31) As Byte
            Dim temp As Byte() = Hash_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass))
            Array.Copy(temp, 0, hash, 0, 16)
            Array.Copy(temp, 0, hash, 15, 16)
            AES.Key = hash
            AES.Mode = Security.Cryptography.CipherMode.ECB
            Dim DESDecrypter As System.Security.Cryptography.ICryptoTransform = AES.CreateDecryptor
            Dim Buffer As Byte() = Convert.FromBase64String(input)
            decrypted = System.Text.ASCIIEncoding.ASCII.GetString(DESDecrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
            Return decrypted
        Catch ex As Exception
        End Try
    End Function

How to Catching the close button event click

This is an example code for knowing when we click on close button:

Example 1:

Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        MessageBox.Show("Closing Form")
End Sub

Example 2:

Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        If boolCloseByButton Then
           'Closed by a different button          
        Else
           'Closed by the x on the form
        End If
End Sub


Example 3:

Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
    'You could put a Select Case statement here and take action for all
    'different types of closing conditions.    
    If e.CloseReason = System.Windows.Forms.CloseReason.UserClosing Then
          'Closed by the x on the form or Alt-F4
    Else  
          'Closed for some other reason      
             
    End If

End Sub

hex to string conversion

This is an example of  hex to string:

Function HexToString(ByVal hex As String) As String
    Dim text As New System.Text.StringBuilder(hex.Length \ 2)
    For i As Integer = 0 To hex.Length - 2 Step 2
        text.Append(Chr(Convert.ToByte(hex.Substring(i, 2), 16)))
    Next
    Return text.ToString
End Function

How to use:

Console.WriteLine(HexToString("73696D306E"))

Getting JSTL to run within Tomcat and Eclipse

It's very simple to include jstl in your projects, what I do is:

1. Download jstl-1.2.jar (JSP 2.1 containers only i.e. Tomcat 6, otherwise jstl-1.1.jar) fromhttp://repo1.maven.org/maven2/javax/servlet/jstl/1.2/
   or
   the interfaces (javax.servlet.jsp.jstl-api-1.2.1.jar) from http://search.maven.org/#browse|707331597and the actual implementing classes (javax.servlet.jsp.jstl-1.2.2.jar) fromhttp://search.maven.org/#browse%7C-1002239589.
2. Copy to your project's WEB-INF/lib directory
3. Include the following tags in yours jsp's:
   • <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   • <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
   • <%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
   • <%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>

As for eclipse I need to know if your using any framework plugin, I use MyEclipse and it does it automatically for me.

VB.NET Split

The Split function separates Strings. It receives a string or character delimiter. It parses and separates the source string by separating the parts that come between the delimiter. It is used often in VB.NET programs.

Notes:Input string = "Dot Net Perls".
Delimiter = space.
Output array = "Dot" "Net" "Perls".

Example

To start, we split a VB.NET String based on a space character. We allocate a New Char array as well as a String array to store the words. Finally we loop over the Strings and display them to the Console.

Char ArrayString Array

Program that uses Split on String: VB.NET

Module Module1

    Sub Main()
 ' We want to split this input string
 Dim s As String = "there is a cat"

 ' Split string based on spaces
 Dim words As String() = s.Split(New Char() {" "c})

 ' Use For Each loop over words and display them
 Dim word As String
 For Each word In words
     Console.WriteLine(word)
 Next
    End Sub

End Module

Output

there
is
a
cat

File path parts

Continuing on, we Split a file system path into separate parts using Visual Basic .NET. We use a New Char array with one string, "\""c. We then loop through and display the results.

Program that splits file path: VB.NET

Module Module1

    Sub Main()
 ' The file system path we need to split
 Dim s As String = "C:\Users\Sam\Documents\Perls\Main"

 ' Split the string on the backslash character
 Dim parts As String() = s.Split(New Char() {"\"c})

 ' Loop through result strings with For Each
 Dim part As String
 For Each part In parts
     Console.WriteLine(part)
 Next
    End Sub

End Module

Output

C:
Users
Sam
Documents
Perls
Main

Regex.Split words

Often you need to extract the words from a String or sentence. The code here needs to handle punctuation and non-word characters differently than the String Split method. Here we use Regex.Split to parse the words.

Program that splits words: VB.NET

Imports System.Text.RegularExpressions

Module Module1

    Sub Main()
 ' Declare iteration variable
 Dim s As String

 ' Loop through words in string
 Dim arr As String() = SplitWords("That is a cute cat, man!")

 ' Display each word. Note that punctuation is handled correctly.
 For Each s In arr
     Console.WriteLine(s)
 Next
 Console.ReadLine()
    End Sub

    ''' <summary>
    ''' Split the words in string on non-word characters.
    ''' This means commas and periods are handled correctly.
    ''' </summary>
    Private Function SplitWords(ByVal s As String) As String()
 '
 ' Call Regex.Split function from the imported namespace.
 ' Return the result array.
 '
 Return Regex.Split(s, "\W+")
    End Function

End Module

Output

That
is
a
cute
cat
man

In the Main subroutine you can see that two variables are declared. The second variable is a String array that receives the results from the Private Function next. This is the SplitWords Function.

Regex. The Function shown in the example calls the Regex.Split method, which can be accessed with dot notation, with no instance necessary. The second argument to the method is a regular expression pattern.

Regex.Split

Regex pattern. The pattern "\W+" is used, and this means "one or more non-word characters". This pattern will match punctuation and spaces. Therefore all those characters will be used as delimiters.

Note:Regex Functions tend to be slower. They can handle much more complex patterns than the String Split Function.

And:It is best to use the fastest and simplest Function that handles your problem.

File lines

Next, we see one way to Split each line in a file using File.ReadAllLines and Split. We have a comma-separated-values CSV file, and want to print out each value and its row number. It first reads in the file with ReadAllLines.

Then:This function puts each line in the file into an array element. The example Splits on ","c. We show the output of the program.

File Handling

Input file used

frontal,parietal,occipital,temporal
pulmonary artery,aorta,left ventricle

Program that splits lines: VB.NET

Imports System.IO

Module Module1
    Sub Main()
 Dim i As Integer = 0

 ' Loop through each line in array returned by ReadAllLines
 Dim line As String
 For Each line In File.ReadAllLines("example.txt")

     ' Split line on comma
     Dim parts As String() = line.Split(New Char() {","c})

     ' Loop over each string received
     Dim part As String
     For Each part In parts
  ' Display to Console
  Console.WriteLine("{0}:{1}", i, part)
     Next
     i += 1
 Next
    End Sub
End Module

Output

0:frontal
0:parietal
0:occipital
0:temporal
1:pulmonary artery
1:aorta
1:left ventricle

Summary

We saw some ways to Split your String in VB.NET. Split returns a String array that you can use in a For Each loop. We used Split on different characters and strings. Then we called Regex.Split in a more complex pattern example.

Convert a String to Stream

Why have you converted binary (image) data to a string? This makes no sense... unless you are using base-64?

Anyway, to reverse what you have done, you could try using new MemoryStream(Encoding.UTF8.GetBytes(text))?

This will create a new MemoryStream primed with the string (via UTF8). Personally, I doubt it will work - you are going to run into a lot of encoding issues treating raw binary as UTF8 data... I expect either the read or write (or both) to throw an exception.

(edit)

I should add that to work with base-64, simply get the data as a byte[], then call Convert.ToBase64String(...); and to get back the array, just use Convert.FromBase64String(...).

Re your edit, this is precisely what I tried to warn about above... in .NET, a string is not just a byte[], so you can't simply fill it with binary image data. A lot of the data simply won't make sense to the encoding, so might be quietly dropped (or an exception thrown).

To handle raw binary (such as images) as strings, you need to use base-64 encoding; this adds size, however. Note that WebClient might make this simpler, as it exposes byte[] functionality directly:

using(WebClient wc = new WebClient()) {
    byte[] raw = wc.DownloadData("http://www.google.com/images/nav_logo.png")
    //...
}
Anyway, using a standard Stream approach, here's how to encode and decode the base-64:

        // ENCODE
        // where "s" is our original stream
        string base64;
        // first I need the data as a byte[]; I'll use
        // MemoryStream, as a convenience; if you already
        // have the byte[] you can skip this
        using (MemoryStream ms = new MemoryStream())
        {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = s.Read(buffer, 0, buffer.Length)) > 0)
            {
                ms.Write(buffer, 0, bytesRead);
            }
            base64 = Convert.ToBase64String(ms.GetBuffer(), 0, (int) ms.Length);
        }

        // DECODE
        byte[] raw = Convert.FromBase64String(base64);
        using (MemoryStream decoded = new MemoryStream(raw))
        {
            // "decoded" now primed with the binary
        }

How to encrypt and decrypt data in Java?

Symmetric Encryption

Symmetric encryption uses the same key for both encryption and decryption. In Java, use an instance of javax.crypto.Cipher. Example:

import java.security.*;
import javax.crypto.*;

Cipher aes = Cipher.getInstance("AES/ECB/PKCS5Padding");
aes.init(Cipher.ENCRYPT_MODE, key);
byte[] ciphertext = aes.doFinal("my cleartext".getBytes());

aes.init(Cipher.DECRYPT_MODE, key);
String cleartext = new String(aes.doFinal(ciphertext));

The key for the cipher should be an instance of javax.crypto.spec.SecretKeySpec. AES in particular requires its key to be created with exactly 128 bits (16 bytes).

A simple way to get the required number of bytes is to take a variable length passphrase and hash it with a java.security.MessageDigest such as SHA1. For example:

import java.security.*;
import javax.crypto.spec.*;

String passphrase = "correct horse battery staple";
MessageDigest digest = MessageDigest.getInstance("SHA");
digest.update(passphrase.getBytes());
SecretKeySpec key = new SecretKeySpec(digest.digest(), 0, 16, "AES");

A better way to create a key is with a SecretKeyFactory using a salt:

byte[] salt = "choose a better salt".getBytes();
int iterations = 10000;
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
SecretKey tmp = factory.generateSecret(new PBEKeySpec(passphrase.toCharArray(), salt, iterations, 128));
SecretKeySpec key = new SecretKeySpec(tmp.getEncoded(), "AES");

PBKDF2 is an algorithm specially designed for generating keys from passwords that is considered more secure than a simple SHA1 hash. The salt ensures your encryption won't match another encryption using the same key and cleartext and helps prevent dictionary attacks. The iterations value is an adjustable parameter. Higher values use more computing power, making brute force attacks more difficult.
Asymmetric Encryption

Asymmetric encryption, also called public key encryption, uses a key pair. One part of the key is used to encrypt and the other to decrypt. This allows you to make the encryption key public, allowing anyone to generate messages only you, the holder of the private decryption key, can read. Alternatively, you can encrypt with the private key, useful for digital signatures.

As with symmetric encryption, use an instance of javax.crypto.Cipher:

import java.security.*;

Cipher rsa = Cipher.getInstance("RSA/ECB/PKCS1Padding");
rsa.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] ciphertext = rsa.doFinal("my cleartext".getBytes());

rsa.init(Cipher.DECRYPT_MODE, privateKey);
String cleartext = new String(rsa.doFinal(ciphertext));

In this case the keys will be instances of java.security.PublicKey and java.security.PrivateKey. To generate a new pair:

import java.security.*;

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
KeyPair keyPair = keyPairGenerator.generateKeyPair();
PublicKey publicKey = keyPair.getPublic();
PrivateKey privateKey = keyPair.getPrivate();

Public and private keys can also be transformed into byte arrays for storage and transmission:

import java.security.*;
import java.security.spec.*;

KeyFactory keyFactory = KeyFactory.getInstance("RSA");
byte[] publicKeyBytes = publicKey.getEncoded();
KeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
PublicKey keyFromBytes = keyFactory.generatePublic(keySpec);

Timer in VB.NET

Public Class Form1
    Private _elapseTimerRunning As Boolean = False
    Private _elapseStartTime As DateTime

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        Timer1.Interval = 1000
        Timer1.Enabled = True
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        txtTime.Text = Now.ToString("h:mm:ss tt")
        If _elapseTimerRunning = True Then
            Dim elapsedtime = DateTime.Now.Subtract(_elapseStartTime)
            txtElapsed.Text = String.Format("{0}hr : {1}min : {2}sec", elapsedtime.Hours, elapsedtime.Minutes, elapsedtime.Seconds)
        End If
    End Sub

    Private Sub btnStart_Click(sender As Object, e As EventArgs) Handles btnStart.Click
        _elapseStartTime = DateTime.Now
        _elapseTimerRunning = True
    End Sub

    Private Sub btnStop_Click(sender As Object, e As EventArgs) Handles btnStop.Click
        _elapseTimerRunning = False
    End Sub
End Class

Timer to count down in VB.Net 2010

This is an example of using VB.NET to count down time:

Public Class frmSinglePlayer

    Private TargetDT As DateTime
    Private CountDownFrom As TimeSpan = TimeSpan.FromMinutes(3)

    Private Sub frmSinglePlayer_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        tmrCountdown.Interval = 500
        TargetDT = DateTime.Now.Add(CountDownFrom)
        tmrCountdown.Start()
    End Sub

    Private Sub tmrCountdown_Tick(sender As Object, e As System.EventArgs) Handles tmrCountdown.Tick
        Dim ts As TimeSpan = TargetDT.Subtract(DateTime.Now)
        If ts.TotalMilliseconds > 0 Then
            lblTime.Text = ts.ToString("mm\:ss")
        Else
            lblTime.Text = "00:00"
            tmrCountdown.Stop()
            MessageBox.Show("Done")
        End If
    End Sub
End Class

Insert SQL command with Datetime in MS-Access

Date & Time input in access use #, since access can't do auto conversion from char/text into date or time in SQL Query (or access call it query), and you better use international standard for inputting date time which was YYYY-MM-DD HH:NN:SS (4-digit year, 2-digit month, 2-digit day, 2-digit hour, 2-digit minute, 2-digit second)

so for 4/21/2009 2:25:53 PM use #2009-04-21 14:25:53#

or if it still fail, you can use #'2009-04-21 14:25:53'#

Edit: Above might be working if you enable ANSI 92 or using ADO/OLEDB as database interface, thanks David for pointing out

I suggest you use YYYY-MM-DD HH:NN:SS format and try it with single quotes (') before use # like i said above

Best way to use PHP to encrypt and decrypt passwords?

You should not encrypt passwords, instead you should hash them using an algorithm like bcrypt. Still, here is how you would encrypt/decrypt:

$key = 'password to (en/de)crypt';
$string = ' string to be encrypted '; // note the spaces

To Encrypt:

$iv = mcrypt_create_iv(
    mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC),
    MCRYPT_DEV_URANDOM
);

$encrypted = base64_encode(
    $iv .
    mcrypt_encrypt(
        MCRYPT_RIJNDAEL_256,
        hash('sha256', $key, true),
        $string,
        MCRYPT_MODE_CBC,
        $iv
    )
);

To Decrypt:

$data = base64_decode($encrypted);
$iv = substr($data, 0, mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC));

$decrypted = rtrim(
    mcrypt_decrypt(
        MCRYPT_RIJNDAEL_256,
        hash('sha256', $key, true),
        substr($data, mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC)),
        MCRYPT_MODE_CBC,
        $iv
    ),
    "\0"
);

---

Demo at IDEOne.com:

echo 'Encrypted:' . "\n";
var_dump($encrypted); // "ey7zu5zBqJB0rGtIn5UB1xG03efyCp+KSNR4/GAv14w="

echo "\n";

echo 'Decrypted:' . "\n";
var_dump($decrypted); // " string to be encrypted "

Found this class recently, it works like a dream!
class Encryption {
    var $skey = "yourSecretKey"; // you can change it

    public  function safe_b64encode($string) {
        $data = base64_encode($string);
        $data = str_replace(array('+','/','='),array('-','_',''),$data);
        return $data;
    }

    public function safe_b64decode($string) {
        $data = str_replace(array('-','_'),array('+','/'),$string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }

    public  function encode($value){ 
        if(!$value){return false;}
        $text = $value;
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->skey, $text, MCRYPT_MODE_ECB, $iv);
        return trim($this->safe_b64encode($crypttext)); 
    }

    public function decode($value){
        if(!$value){return false;}
        $crypttext = $this->safe_b64decode($value); 
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->skey, $crypttext, MCRYPT_MODE_ECB, $iv);
        return trim($decrypttext);
    }
}

And to call it:
$str = "My secret String";

$converter = new Encryption;
$encoded = $converter->encode($str );
$decoded = $converter->decode($encoded);    

echo "$encoded<p>$decoded";