Question

am [writing reading] from a plain text file usernames and passwords, but its an bad way of securing data, is there any other way to do this, most probably by using IV’s, encryption decryption algorithms.

Answer 1

You can encode your passwords with HASHES like SHA1.

Function getSHA1Hash(ByVal strToHash As String) As String

  Dim sha1Obj As New Security.Cryptography.SHA1CryptoServiceProvider
  Dim bytesToHash() As Byte = System.Text.Encoding.ASCII.GetBytes(strToHash)

  bytesToHash = sha1Obj.ComputeHash(bytesToHash)

  Dim strResult As String = ""

  For Each b As Byte In bytesToHash
      strResult += b.ToString("x2")
  Next

  Return strResult

End Function

Using it is simple!

Console.Write(getSHA1Hash("password"))

So whenever you need to authenticate a user, you can take his input password, compute a hash of it using the above function and make sure it’s the same with a simple IF clause:

if getSHA1Hash(input_password) = HASHED_OLD_PASSWORD then Authenticate()

SHA1 hashes aren’t decryptable without sheer brute forcing every possibility so it’s a pretty safe solution.