Simple Encryption and Decryption Function using rijndael algorithm.
Imports this:
Imports System.Security
Imports System.Security.Cryptography
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Text.RegularExpressions
Imports System.Text
Source : [snipped]
Public Function Encrypt(ByVal plainText As String) As String
Dim passPhrase As String = "yourPassPhrase"
Dim saltValue As String = "mySaltValue"
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
Dim plainTextBytes As Byte() = Encoding.UTF8.GetBytes(plainText)
Dim password As New PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations)
Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
Dim symmetricKey As New RijndaelManaged()
symmetricKey.Mode = CipherMode.CBC
Dim encryptor As ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)
Dim memoryStream As New MemoryStream()
Dim cryptoStream As New CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)
cryptoStream.FlushFinalBlock()
Dim cipherTextBytes As Byte() = memoryStream.ToArray()
memoryStream.Close()
cryptoStream.Close()
Dim cipherText As String = Convert.ToBase64String(cipherTextBytes)
Return cipherText
End Function
Public Function Decrypt(ByVal cipherText As String) As String
Dim passPhrase As String = "yourPassPhrase"
Dim saltValue As String = "mySaltValue"
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
' Convert strings defining encryption key characteristics 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() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
' Convert our ciphertext into a byte array.
Dim cipherTextBytes As Byte() = Convert.FromBase64String(cipherText)
' 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 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() = password.GetBytes(keySize \ 8)
' Create uninitialized Rijndael encryption object.
Dim symmetricKey As 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 decryptor from the existing key bytes and initialization
' vector. Key size will be defined based on the number of the key
' bytes.
Dim decryptor As ICryptoTransform = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)
' Define memory stream which will be used to hold encrypted data.
Dim memoryStream As New MemoryStream(cipherTextBytes)
' Define cryptographic stream (always use Read mode for encryption).
Dim cryptoStream As New CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)
' Since at this point we don't know what the size of decrypted data
' will be, allocate the buffer long enough to hold ciphertext;
' plaintext is never longer than ciphertext.
Dim plainTextBytes As Byte() = New Byte(cipherTextBytes.Length - 1) {}
' Start decrypting.
Dim decryptedByteCount As Integer = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length)
' Close both streams.
memoryStream.Close()
cryptoStream.Close()
' Convert decrypted data into a string.
' Let us assume that the original plaintext string was UTF8-encoded.
Dim plainText As String = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount)
' Return decrypted string.
Return plainText
End Function
Example :
Dim strEncryptedText As String
strEncryptedText = Encrypt("yourEncryptionText")
Dim strDecrptedText As String
strDecrptedText = Decrypt(strEncryptedText)
Rijndael algorithm is quite good and has already been shared here. Thanks though.
I have no idea how it works... But cool!
I might use this rather than just saving passwords to a text file.
But would other programs with this code be able to decode the data?
Thanks.
But would other programs with this code be able to decode the data?
I'm not quite certain since cryptography is a new field for me, though I do believe that this: Dim saltValue As String = "mySaltValue" is what makes your .app unique. Changing the value to anything, should only allow your app to decode it and none other.
Hi sandeepparekh9,
I tried your code in my program, but I'm unable to encrypt the password, could you help me out, im new to encryption, it's my first time.
Imports System.Data.SqlClient
Imports System.Data
Imports System.Windows.Forms
Imports System.Security
Imports System.Security.Cryptography
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Text.RegularExpressions
Imports System.Text
Public Class LoginForm1
Dim DT As New DataTable
Dim QUERYSTRING As String
Dim I As Integer = 0
Dim constring As New SqlConnection(My.Settings.PERDBConnectionString)
Public count As Integer
Private Sub Login_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Login.Click
Try
If constring.State = ConnectionState.Open Then
constring.Close()
End If
constring.Open()
Dim MainMenu As New MDIParent1
Dim result As String
Dim CMD As New SqlCommand
CMD.Connection = constring
CMD.CommandText = "Exec validatelogin '" & txtuserid.Text & "','" & txtpwd.Text & "'"
Dim ad As New SqlDataAdapter(CMD)
Dim dt As New DataTable
result = CMD.ExecuteScalar
ad.Fill(dt)
MsgBox(result, MsgBoxStyle.Exclamation)
If result = "True" And CheckBox1.CheckState = 0 Then
MainMenu.Show()
Me.Dispose(False)
Else
MsgBox("Username or Password appears to be wrong")
End If
constring.Close()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.ApplicationModal)
End Try
End Sub
Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
Dim result As String
Dim CMD As New SqlCommand
CMD.Connection = constring
Try
If constring.State = ConnectionState.Open Then
constring.Close()
End If
constring.Open()
If CheckBox1.CheckState = 1 Then
CMD.CommandText = "Exec validatelogin '" & txtuserid.Text & "','" & txtpwd.Text & "'"
Dim ad As New SqlDataAdapter(CMD)
Dim dt As New DataTable
result = CMD.ExecuteScalar
ad.Fill(dt)
If result = "True" Then
Height = 655
Width = 466
Else
MsgBox("Username or Password appears to be wrong")
End If
ElseIf CheckBox1.CheckState = 0 Then
Height = 289
Width = 462
End If
constring.Close()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.ApplicationModal)
End Try
End Sub
Private Sub btnSave_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
Try
Dim sqlparameter(2) As Object
sqlparameter(0) = txtuserid.Text
sqlparameter(1) = txtoldpwd.Text
sqlparameter(2) = txtnewpwd.Text
While CheckBox1.CheckState = 1
If constring.State = ConnectionState.Open Then
constring.Close()
End If
constring.Open()
Dim CMD As New SqlCommand
CMD.Connection = constring
Dim commandstring As String = " '"
Dim msg As String
Dim ad As New SqlDataAdapter
Dim dt As New DataTable
Dim strEncryptedText As String
For Each Str As String In sqlparameter
commandstring &= Str & "','"
Next
If String.IsNullOrEmpty(txtuserid.Text) OrElse String.IsNullOrEmpty(txtpwd.Text) OrElse String.IsNullOrEmpty(txtoldpwd.Text) OrElse String.IsNullOrEmpty(txtnewpwd.Text) Then
MsgBox("All fields need to be filled")
Exit Sub
End If
commandstring = Mid(commandstring, 1, (Len(commandstring) - 2))
CMD.CommandText = "Exec updatelog " & commandstring
msg = CMD.ExecuteScalar()
'ad.Fill(dt)
strEncryptedText = Encrypt("txtpwd.Text")
If txtoldpwd.Text = txtpwd.Text Then
MsgBox("password changed")
Exit Sub
Else
MsgBox("password is mismatched")
Exit Sub
End If
constring.Close()
End While
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.ApplicationModal)
End Try
End Sub
Public Function Encrypt(ByVal plainText As String) As String
Dim passPhrase As String = "Password"
Dim saltValue As String = "mySaltValue"
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
Dim plainTextBytes As Byte() = Encoding.UTF8.GetBytes(plainText)
Dim password As New PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations)
Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
Dim symmetricKey As New RijndaelManaged()
symmetricKey.Mode = CipherMode.CBC
Dim encryptor As ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)
Dim memoryStream As New MemoryStream()
Dim cryptoStream As New CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)
cryptoStream.FlushFinalBlock()
Dim cipherTextBytes As Byte() = memoryStream.ToArray()
memoryStream.Close()
cryptoStream.Close()
Dim cipherText As String = Convert.ToBase64String(cipherTextBytes)
Return cipherText
End Function
Public Function Decrypt(ByVal cipherText As String) As String
Dim passPhrase As String = "Password"
Dim saltValue As String = "mySaltValue"
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
Dim cipherTextBytes As Byte() = Convert.FromBase64String(cipherText)
Dim password As New PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations)
Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
Dim symmetricKey As New RijndaelManaged()
symmetricKey.Mode = CipherMode.CBC
Dim decryptor As ICryptoTransform = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)
Dim memoryStream As New MemoryStream(cipherTextBytes)
Dim cryptoStream As New CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)
Dim plainTextBytes As Byte() = New Byte(cipherTextBytes.Length - 1) {}
Dim decryptedByteCount As Integer = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length)
memoryStream.Close()
cryptoStream.Close()
Dim plainText As String = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount)
Return plainText
End Function
End Class
strEncryptedText = Encrypt("txtpwd.Text")
prancode, on line 153 of the above code, I presume you are trying to encrypt the contents of the txtpwd text box. To do so, you need to remove the quotes... it should be like this;
strEncryptedText = Encrypt(txtpwd.Text)
I had to make a couple of changes, but for the most part entered it as you had it. It seems to encrypt fine but stops at the decryptedByteCount declaration. The error says "Length of the data to decrypt is invalid".
I was just encrypting it to a text box and then trying to decrypt that text box to another.
One change I had to make was that the compiler would not compile "PasswordDeriveBytes" instead it said that it was obsolete and that "Rfc2898DeriveBytes" had replaced it.
The new one only accepts 3 parameters and not the hashAlgorithm.
I would appreciate it if anyone could tell me how to make this work. I am using Visual Studio 2012.
Imports System.Security
Imports System.Security.Cryptography
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Text.RegularExpressions
Imports System.Text
Module Encrypt2
Public passPhrase As String = "yourPassPhrase"
Public saltValue As String = "mySaltValue"
Dim hashAlgorithm As String = "SHA1"
Public Function Encrypt(ByVal plainText As String) As String
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
Dim plainTextBytes As Byte() = Encoding.UTF8.GetBytes(plainText)
Dim password As New Rfc2898DeriveBytes(passPhrase, saltValueBytes, passwordIterations)
Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
Dim symmetricKey As New RijndaelManaged()
symmetricKey.Mode = CipherMode.CBC
Dim encryptor As ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)
Dim memoryStream As New MemoryStream()
Dim cryptoStream As New CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)
cryptoStream.FlushFinalBlock()
Dim cipherTextBytes() = memoryStream.ToArray()
memoryStream.Close()
cryptoStream.Clear()
Dim cipherText As String = Convert.ToBase64String(cipherTextBytes)
Return cipherText
End Function
Public Function Decrypt(ByVal cipherText As String) As String
Dim hashAlgorithm As String = "SHA1"
Dim passwordIterations As Integer = 2
Dim initVector As String = "@1B2c3D4e5F6g7H8"
Dim keySize As Integer = 256
' Convert strings defining encryption key characteristics 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() = Encoding.ASCII.GetBytes(initVector)
Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)
' Convert the Ciphertext into a Byte array
Dim cipherTextBytes As Byte() = Encoding.UTF8.GetBytes(cipherText)
' 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 crated using
' the specified hash algorithm. Password creation can be done in
' several iterations
Dim password As New Rfc2898DeriveBytes(passPhrase, saltValueBytes, 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() = password.GetBytes(keySize \ 8)
' Create uninitialized Rijndael encryption object
Dim symmetricKey As 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 decryptor from the existing key bytes and initialization
' vector. Key size will be defined based on the number of the key
'bytes
Dim decryptor As ICryptoTransform = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)
' Define memory stream which will be used to hold encrypted data.
Dim memoryStream As New MemoryStream(cipherTextBytes)
' Define cryptographic stream (always user Read mode for encryption).
Dim cryptoStream As New CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)
' Since at this point we don't know what the size of decrypted data
' will be, allocate the buffer long enough to hold ciphertext;
' plaintext is never longer than ciphertext
Dim plainTextBytes As Byte() = New Byte(cipherTextBytes.Length - 1) {}
' Start decrypting.
Dim decryptedByteCount As Integer = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length)
' Close both streams
memoryStream.Close()
cryptoStream.Close()
' Convert decrypted data into a string
' Let us assume that the original plaintext string was UTF8-Encoded.
Dim plainText As String = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount)
' Return the decrypted string
Return plainText
End Function
End Module
'*******************************************************************
Imports System.Security.Cryptography
Public Class Form1
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
If txt3.TextLength > 0 And txt4.TextLength > 0 Then
txt1.Text = Decrypt(txt3.Text)
txt2.Text = Decrypt(txt4.Text)
End If
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If txt1.Text.Length > 0 And txt2.Text.Length > 0 Then
txt3.Text = Encrypt(txt1.Text)
txt4.Text = Encrypt(txt2.Text)
End If
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
End Class
I meant that I am using Visual Studio 2010. And the program is stopping at line 112.
Hi sandeepparekh9,
I try to use your Encrypt and Decrypt functions and I found if 2 functions stay on the same application it's work but I want to Encrypt at the one web application and Decrypt at the another one web application it decrypt not like the original word that I encrypt .. below is the source and the word that I want to encrypt is "SV00760" and now the resault after decrypt is "»dǃ:/}/" ..
Sandeep
Many thanks for taking the time to post this code.
I have tested this on multiple languages and found that it works with all of the supported international languages in Windows 7.
Well done, and keep up the good work.
Kind Regards, Garry@TriSys
I get "invalid length for a base-64 char array" in below line when i try to use it in Asp.net
' Convert the Ciphertext into a Byte array
Dim cipherTextBytes As Byte() = Encoding.UTF8.GetBytes(cipherText)
Hey. This is really cool!!! But there is one thing I need to ask you. How do I decrypt a certain file. e.g. my program creates a file which stores a password. Once the file is saved it will add the encryption. So if the file is opend outside e.g. using notepad wordpad it will show the encryption key rather than the password and if the file is opened from my program it should show the password.
How can this be done. I'd love to use your encryption method in that form.
Thank You!
What you do is encrypt the text before you write it to the file. Then after you read it back in you decrypt it
app -> encrypt -> file
file -> decrypt -> app
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