Aplikasi MD5 (Message Diggest Algorithm 5) "ENCRYPT & DECRYPT" pada VB.Net

oke ini terinspirasi dari Tugas Kuliah baru-baru ini.

so mari mengenal MD5

Dalam kriptografi, MD5 (Message-Digest algortihm 5) ialah fungsi hash kriptografik yang digunakan secara luas dengan hash value 128-bit. Pada standart Internet (RFC 1321), MD5 telah dimanfaatkan secara bermacam-macam pada aplikasi keamanan, dan MD5 juga umum digunakan untuk melakukan pengujian integritas sebuah file.

MD5 di desain oleh Ronald Rivest pada tahun 1991 untuk menggantikan hash function sebelumnya, MD4. Pada tahun 1996, sebuah kecacatan ditemukan dalam desainnya, walau bukan kelemahan fatal, pengguna kriptografi mulai menganjurkan menggunakan algoritma lain, seperti SHA-1 (klaim terbaru menyatakan bahwa SHA-1 juga cacat). Pada tahun 2004, kecacatan-kecacatan yang lebih serius ditemukan menyebabkan penggunaan algoritma tersebut dalam tujuan untuk keamanan jadi makin dipertanyakan.

oke cukup pengetahuan singkatnya mengenai MD5.

sekarang buatlah form seperti dibawah ini atau ya terserah lah yang penting ada tools

jangan lupa menabahkan "References" "System.Security" ".NET"

Menu-Project-Add Reference-TAB .NET-System.Security

nah sekarang tulislah koding seperti dibawah ini

Imports System.Security.Cryptography

Public Class ENKRIPSI_DESKRIPSI

  Dim FuncCls As New CommonFunctionsCls()

  Public Class EncryptDecryptClass

  Private Shared m_strPassPhrase As String = "MyPriv@Password!$$"
  Private Shared m_strHashAlgorithm As String = "MD5"
  Private Shared m_strPasswordIterations As Integer = 2
  Private Shared m_strInitVector As String = "@1B2c3D4e5F6g7H8"
  Private Shared m_intKeySize As Integer = 256

  'Encrypt Function: 
  Friend Shared Function EncryptPasswordMD5(ByVal plainText As String, ByVal p_strSaltValue As String) As String

  Dim strReturn As String = String.Empty

  Try
  Dim initVectorBytes As Byte()
  initVectorBytes = System.Text.Encoding.ASCII.GetBytes(m_strInitVector)

  Dim saltValueBytes As Byte()
  saltValueBytes = System.Text.Encoding.ASCII.GetBytes(p_strSaltValue)

  Dim plainTextBytes As Byte()
  plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText)

  Dim password As Rfc2898DeriveBytes

  password = New Rfc2898DeriveBytes(m_strPassPhrase, _
  saltValueBytes, _
  m_strPasswordIterations)
  Dim keyBytes As Byte()
  Dim intKeySize As Integer = 0

  intKeySize = CType((m_intKeySize / 8), Integer)

  keyBytes = password.GetBytes(intKeySize)

  Dim symmetricKey As System.Security.Cryptography.RijndaelManaged
  symmetricKey = New System.Security.Cryptography.RijndaelManaged

  symmetricKey.Mode = System.Security.Cryptography.CipherMode.CBC

  Dim encryptor As System.Security.Cryptography.ICryptoTransform
  encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)

  Dim memoryStream As System.IO.MemoryStream
  memoryStream = New System.IO.MemoryStream

  Dim cryptoStream As System.Security.Cryptography.CryptoStream
  cryptoStream = New System.Security.Cryptography.CryptoStream(memoryStream, _
  encryptor, _
  System.Security.Cryptography.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.
  strReturn = cipherText

  Catch ex As Exception
  strReturn = Nothing
  End Try

  Return strReturn

  End Function

  'Decrypt Function: 
  Friend Shared Function DecryptPasswordMD5(ByVal cipherText As String, ByVal p_strSaltValue As String) As String

  Dim strReturn As String = String.Empty

  Try

  Dim initVectorBytes As Byte()
  initVectorBytes = System.Text.Encoding.ASCII.GetBytes(m_strInitVector)

  Dim saltValueBytes As Byte()
  saltValueBytes = System.Text.Encoding.ASCII.GetBytes(p_strSaltValue)

  Dim cipherTextBytes As Byte()
  cipherTextBytes = Convert.FromBase64String(cipherText)

  Dim password As Rfc2898DeriveBytes

  password = New Rfc2898DeriveBytes(m_strPassPhrase, _
  saltValueBytes, _
  m_strPasswordIterations)

  Dim keyBytes As Byte()
  Dim intKeySize As Integer

  intKeySize = CType((m_intKeySize / 8), Integer)

  keyBytes = password.GetBytes(intKeySize)

  Dim symmetricKey As System.Security.Cryptography.RijndaelManaged
  symmetricKey = New System.Security.Cryptography.RijndaelManaged

  symmetricKey.Mode = System.Security.Cryptography.CipherMode.CBC

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

  Dim memoryStream As System.IO.MemoryStream
  memoryStream = New System.IO.MemoryStream(cipherTextBytes)

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

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

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

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

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

  ' Return decrypted string.
  strReturn = plainText

  Catch ex As Exception
  strReturn = Nothing
  End Try

  Return strReturn


  End Function

  End Class

  Public Class CommonFunctionsCls

  Public Function EncryptPassword(ByVal Password As String) As String

  'Encrypt the Password
  Dim sEncryptedPassword As String = ""
  Dim sEncryptKey As String = "P@SSW@RD@09" 'Should be minimum 8 characters

  Try
  sEncryptedPassword = EncryptDecryptClass.EncryptPasswordMD5(Password, sEncryptKey)

  Catch ex As Exception
  Return sEncryptedPassword
  End Try

  Return sEncryptedPassword
  End Function

  Public Function DecryptPassword(ByVal Password As String) As String

  'Encrypt the Password
  Dim sDecryptedPassword As String = ""
  Dim sEncryptKey As String = "P@SSW@RD@09" 'Should be minimum 8 characters

  Try
  sDecryptedPassword = EncryptDecryptClass.DecryptPasswordMD5(Password, sEncryptKey)

  Catch ex As Exception
  Return sDecryptedPassword
  End Try

  Return sDecryptedPassword
  End Function
  End Class

  Private Sub BtnENKRIPSI_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnENKRIPSI.Click

  TxtENKRIP.Text = FuncCls.EncryptPassword(TxtPASSWORD.Text.Trim)

  End Sub

  Private Sub BtnDEKRIPSI_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDEKRIPSI.Click

  TxtDEKRIP.Text = FuncCls.DecryptPassword(TxtENKRIP.Text.Trim)

  End Sub

  Private Sub BtnCLEAR_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCLEAR.Click

  TxtPASSWORD.Text = ""
  TxtENKRIP.Text = ""
  TxtDEKRIP.Text = ""

  TxtENKRIP.Focus()

  End Sub

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

  Me.Close()

  End Sub

End Class

run aplikasinya maka akan running seperti dibawah, isilah teks Password dan klik buttonnya untuk mengetahui hasil tersebut