How to implement Strong cryptography with associated key-management processes and procedures in order to handle Credit Card information as per PCI standards in .Net Web application

In order to encrypt Data you should use the following sub:

Public Function EncodePassword(password As String) As String
            Dim encodedPassword As String = password
            Select Case pPasswordFormat
                Case MembershipPasswordFormat.Clear
                Case MembershipPasswordFormat.Encrypted
                    encodedPassword = _
                      Convert.ToBase64String(EncryptPassword(Encoding.Unicode.GetBytes(password)))
                Case MembershipPasswordFormat.Hashed
                    Dim hash As HMACSHA384 = New HMACSHA384()
                    hash.Key = HexToByte(pMachineKey.ValidationKey)
                    encodedPassword = Convert.ToBase64String(hash.ComputeHash(Encoding.Unicode.GetBytes(password)))
                Case Else
                    ErrorAnswer = "Password format not supported."
                    '------Handle it as you like...........
                    Return Nothing
            End Select
           
            Return encodedPassword.ToLower
        End Function

In the web.config file you should add the line:

<machinekey validationkey="C50B3C89CB21F4F1422FF158A5B42D0E8DB8CB5CDA1742572A487D9401E3400267682B202B746511891C1BAF47F8D25C07F6C39A104696DB51F17C529AD3CABE">
                decryptionKey="8A9BE8FD67AF6979E7D20198CFEA50DD3D3799C77AF2B72F" 
                validation="HMACSHA384" decryption="AES" /></machinekey>

And also if you want to make it more stronger.... please "Salt it" with the following sub:

Public Shared Function GetSaltKey() As String
            Dim saltBytes() As Byte
            Dim minSaltSize As Integer = 256
            Dim maxSaltSize As Integer = 512
            ' Generate a random number for the size of the salt.
            Dim random As Random
            random = New Random()
            Dim saltSize As Integer
            saltSize = random.Next(minSaltSize, maxSaltSize)
            ' Allocate a byte array, which will hold the salt.
            saltBytes = New Byte(saltSize - 1) {}
            ' Initialize a random number generator.
            Dim rng As RNGCryptoServiceProvider
            rng = New RNGCryptoServiceProvider()
            ' Fill the salt with cryptographically strong byte values.
            rng.GetNonZeroBytes(saltBytes)
            ' Convert plain text into a byte array.
            Return Convert.ToBase64String(saltBytes)
        End Function

Please... if you want to "salt" your data then do it outside of the Encryption Function because you want later to use the same "salt" to Encode the new coming input in order to compare with the written on your data base.
If you choose to "salt" the encoded data and keep the "salt" then you need to produce a record in your database with nvarchar(1024) and of course all the related "records declares" needs to be in the same Length.
Pay attention that this encode method is made with the SAH3 which is the most stronger method for encryption.
I don't know if I give you the answer you want it.... but in any case I've try it to!!!