[VS 2008] Strong encryption and hashing class - Updated! 31/August/2009

[tassa]

Updated - August/31/2009

FYI:
Someone asked me if one should use the whole algorithm to encrypt or hash; the answer is NO, if you want to encrypt a string (with AES or Rijndael) then just copy the region and paste it in your code, same thing goes for hashing. The code is divided into regions to serve that purpose.

Updates:

• Added an enumeration to hold the cryptographic actions that can be performed (encryption or decryption).
• Added a function to generate an IV from the given key (after playing around with it ).
• Added an exception handler... Just in case the password isn't the right one.

Hello,

I have been working on this for a while now, I have based my work on Jenner's submission. Since I had noticed that it was for VS 2005, I decided to create my own, for VS 2008...

I have included AES for encryption and used SHA256 for hashing the strings, also some overloads so it'll handle more object types (to permit more "flexibility").

Even though AES and Rijndael ARE THE SAME ALGORITHMS, they have some particularities:

• AES:
• Has a fixed block size of 128bits.
• Allows key sizes of 128, 192 and 256 bits.
  Rijndael:
• Allows block sizes of 128bits, 192bits and 256bits.
• Permits the use of 64, 96, 128, 192, 256 bits key sizes.

(The block size is specific to each algorithm since it indicates which the size of the IV to be used or that is supported by one of these two algorithms.)

Some usage examples:

Imports EncryptDecrypt.SymmetricEncryptionAlgorithms.AESManagedEncryption
Imports EncryptDecrypt.SymmetricEncryptionAlgorithms.RijndaelManagedEncryption
Imports EncryptDecrypt.SHAManagedHash.SHA256ManagedHash
Imports System.Text
 
Module Module1
 
    Sub Main()
        Dim StringToBeEncrypted As String = "Hello world!"
        'AES:
        Dim AESEncryptedString As String = AESEncryptDecrypt(StringToBeEncrypted, "vbforums", _
                                                        AESCryptographicAction.Encrypt)
        Console.WriteLine(AESEncryptedString)
        Console.WriteLine(AESEncryptDecrypt(AESEncryptedString, "vbforums", _
                                            AESCryptographicAction.Decrypt))
        'Rijndael:
        Dim StringBytes As Byte() = Encoding.UTF8.GetBytes(StringToBeEncrypted)
        Dim KeyBytes As Byte() = Encoding.UTF8.GetBytes("tassa")
        Dim RijndaelEncryptedString As String = RijndaelEncryptDecrypt(StringBytes, KeyBytes, _
                                                                       RijndaelCryptographicAction.Encrypt)
        Console.WriteLine(RijndaelEncryptedString)
        Console.WriteLine(RijndaelEncryptDecrypt(RijndaelEncryptedString, KeyBytes, _
                                                 RijndaelCryptographicAction.Decrypt))
        'Hash
        Dim salt As Byte() = Nothing
        Dim hashedString As String = SHA256StringHash("vbforums.com", salt)
        Console.WriteLine(hashedString)
        Console.WriteLine(Convert.ToBase64String(salt))
        'Verify the hash
        Dim checkHash As Boolean = VerifyHash("vbforums.com", hashedString, salt)
        If checkHash = True Then
            Console.WriteLine("It's a match!")
        Else
            Console.WriteLine("It's not a match!")
        End If
        Console.ReadKey()
    End Sub
 
 
End Module

Due to character limitations, the code is in post #2 and #3.

Comments, critics are appreciated!
Hope you like it :P .