Intractive

Purpose : This function will allow you to encrypt data.

Special Note : The mySecurity Class is NOT my code, but is VERY useful and VERY difficult to find, so I figured I would re-post it. If the author of the code has any objections, please message me and it will be removed. The shared variables would be setup in your own class, and then passed to the mySecurity class.

Imports System.IO
Imports System.Security.Cryptography
Imports System.Text

    Shared passPhrase As String = "12345gcwert6789012dg"
    Shared saltValue As String = "s@1tValue"
    Shared hashAlgorithm As String = "SHA1"
    Shared passwordIterations As Integer = 2
    Shared initVector As String = "@1B2c3D4e5F6g7H8" ' must be 16 bytes
    Shared keySize As Integer = 256 ' can be 192 or 128

Public Class mySecurity

    Public Shared Function Encrypt(ByVal plainText As String, _
                                   ByVal passPhrase As String, _
                                   ByVal saltValue As String, _
                                   ByVal hashAlgorithm As String, _
                                   ByVal passwordIterations As Integer, _
                                   ByVal initVector As String, _
                                   ByVal keySize As Integer) _
                           As String

        ' Convert strings into byte arrays.
        ' Let us assume that strings only contain ASCII codes.
        ' If strings include Unicode characters, use Unicode, UTF7, or UTF8 
        ' encoding.
        Dim initVectorBytes As Byte()
        initVectorBytes = Encoding.ASCII.GetBytes(initVector)

        Dim saltValueBytes As Byte()
        saltValueBytes = Encoding.ASCII.GetBytes(saltValue)

        ' Convert our plaintext into a byte array.
        ' Let us assume that plaintext contains UTF8-encoded characters.
        Dim plainTextBytes As Byte()
        plainTextBytes = Encoding.UTF8.GetBytes(plainText)

        ' First, we must create a password, from which the key will be derived.
        ' This password will be generated from the specified passphrase and 
        ' salt value. The password will be created using the specified hash 
        ' algorithm. Password creation can be done in several iterations.
        Dim password As PasswordDeriveBytes
        password = New PasswordDeriveBytes(passPhrase, _
                                           saltValueBytes, _
                                           hashAlgorithm, _
                                           passwordIterations)

        ' Use the password to generate pseudo-random bytes for the encryption
        ' key. Specify the size of the key in bytes (instead of bits).
        Dim keyBytes As Byte()
        keyBytes = password.GetBytes(keySize / 
        ' Create uninitialized Rijndael encryption object.
        Dim symmetricKey As RijndaelManaged
        symmetricKey = New RijndaelManaged()

        ' It is reasonable to set encryption mode to Cipher Block Chaining
        ' (CBC). Use default options for other symmetric key parameters.
        symmetricKey.Mode = CipherMode.CBC

        ' Generate encryptor from the existing key bytes and initialization 
        ' vector. Key size will be defined based on the number of the key 
        ' bytes.
        Dim encryptor As ICryptoTransform
        encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)

        ' Define memory stream which will be used to hold encrypted data.
        Dim memoryStream As MemoryStream
        memoryStream = New MemoryStream()

        ' Define cryptographic stream (always use Write mode for encryption).
        Dim cryptoStream As CryptoStream
        cryptoStream = New CryptoStream(memoryStream, _
                                        encryptor, _
                                        CryptoStreamMode.Write)
        ' Start encrypting.
        cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)

        ' Finish encrypting.
        cryptoStream.FlushFinalBlock()

        ' Convert our encrypted data from a memory stream into a byte array.
        Dim cipherTextBytes As Byte()
        cipherTextBytes = memoryStream.ToArray()

        ' Close both streams.
        memoryStream.Close()
        cryptoStream.Close()

        ' Convert encrypted data into a base64-encoded string.
        Dim cipherText As String
        cipherText = Convert.ToBase64String(cipherTextBytes)

        ' Return encrypted string.
        Encrypt = cipherText
    End Function

    ' <summary>
    ' Decrypts specified ciphertext using Rijndael symmetric key algorithm.
    ' </summary>
    ' <param name="cipherText">
    ' Base64-formatted ciphertext value.
    ' </param>
    ' <param name="passPhrase">
    ' Passphrase from which a pseudo-random password will be derived. The 
    ' derived password will be used to generate the encryption key. 
    ' Passphrase can be any string. In this example we assume that this 
    ' passphrase is an ASCII string.
    ' </param>
    ' <param name="saltValue">
    ' Salt value used along with passphrase to generate password. Salt can 
    ' be any string. In this example we assume that salt is an ASCII string.
    ' </param>
    ' <param name="hashAlgorithm">
    ' Hash algorithm used to generate password. Allowed values are: "MD5" and
    ' "SHA1". SHA1 hashes are a bit slower, but more secure than MD5 hashes.
    ' </param>
    ' <param name="passwordIterations">
    ' Number of iterations used to generate password. One or two iterations
    ' should be enough.
    ' </param>
    ' <param name="initVector">
    ' Initialization vector (or IV). This value is required to encrypt the 
    ' first block of plaintext data. For RijndaelManaged class IV must be 
    ' exactly 16 ASCII characters long.
    ' </param>
    ' <param name="keySize">
    ' Size of encryption key in bits. Allowed values are: 128, 192, and 256. 
    ' Longer keys are more secure than shorter keys.
    ' </param>
    ' <returns>
    ' Decrypted string value.
    ' </returns>
    ' <remarks>
    ' Most of the logic in this function is similar to the Encrypt 
    ' logic. In order for decryption to work, all parameters of this function
    ' - except cipherText value - must match the corresponding parameters of 
    ' the Encrypt function which was called to generate the 
    ' ciphertext.
    ' </remarks>
    Public Shared Function Decrypt(ByVal cipherText As String, _
                                   ByVal passPhrase As String, _
                                   ByVal saltValue As String, _
                                   ByVal hashAlgorithm As String, _
                                   ByVal passwordIterations As Integer, _
                                   ByVal initVector As String, _
                                   ByVal keySize As Integer) _
                           As String
        Dim myReturn As String = Nothing

        Try
            Dim initVectorBytes As Byte()
            initVectorBytes = Encoding.ASCII.GetBytes(initVector)

            Dim saltValueBytes As Byte()
            saltValueBytes = Encoding.ASCII.GetBytes(saltValue)

            ' Convert our ciphertext into a byte array.
            Dim cipherTextBytes As Byte()
            cipherTextBytes = Convert.FromBase64String(cipherText)

            Dim password As PasswordDeriveBytes
            password = New PasswordDeriveBytes(passPhrase, _
                                               saltValueBytes, _
                                               hashAlgorithm, _
                                               passwordIterations)

            Dim keyBytes As Byte()
            keyBytes = password.GetBytes(keySize /  

            Dim symmetricKey As RijndaelManaged
            symmetricKey = New RijndaelManaged()

            symmetricKey.Mode = CipherMode.CBC

            Dim decryptor As ICryptoTransform
            decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)

            Dim memoryStream As MemoryStream
            memoryStream = New MemoryStream(cipherTextBytes)

            Dim cryptoStream As CryptoStream
            cryptoStream = New CryptoStream(memoryStream, _
                                            decryptor, _
                                            CryptoStreamMode.Read)

            Dim plainTextBytes As Byte()
            ReDim plainTextBytes(cipherTextBytes.Length)

            Dim decryptedByteCount As Integer
            decryptedByteCount = cryptoStream.Read(plainTextBytes, _
                                                   0, _
                                                   plainTextBytes.Length)

            memoryStream.Close()
            cryptoStream.Close()

            Dim plainText As String
            plainText = Encoding.UTF8.GetString(plainTextBytes, _
                                                0, _
                                                decryptedByteCount)

            myReturn = plainText
        Catch ex As Exception

        End Try

        Return myReturn
    End Function
End Class