Decrypting Images in VB.NET

Introduction

This is the code to decrypt the encrypted image. I am getting the encrypted string from the database and decrypting it into its original format. We have lots of articles and examples on text decryption and there are no articles and examples on image decryption (I may not search well). That's what I decided to give an example on image decryption.

There are some hard-coded values in the program, so please excuse me for that. I am posting this article here to give a basic idea of how to decrypt an image into its original format. Based on this idea, you can write your own program to decrypt.

This is my frist article here. If there are any voilations of The Code Project's rules, please excuse me.

Using the Code

This code is useful to decrypt images in VB.NET.

Imports System.IO
Imports System.Text
Imports System.Security.Cryptography
Imports System.Data.Odbc
Imports System.Drawing
Imports COZErrorLogging
Imports COZSQLException
Public Class Decryption
    Public Function DecryptImage() As String
        Try
            Dim con As OdbcConnection = New OdbcConnection(_
                "Dsn=mydbdsn;uid=icmadmin;pwd=password;alias=MYDBDATA;")
            con.Open()
            Dim cmd As OdbcCommand = New OdbcCommand(_
                "select SIGNATURE from DSCSIGNATURE_MASTER", con)
            Dim dr As OdbcDataReader = cmd.ExecuteReader()
            Dim key As New DESCryptoServiceProvider()
            Dim keybytes() As Byte = ASCIIEncoding.ASCII.GetBytes("abcdEFGH")
            key.Key = keybytes
            dr.Read()
            Dim rawData() As Byte
            Dim sizeS As String
            sizeS = dr.GetString(0)
            rawData = Convert.FromBase64String(sizeS)
            Dim des As New DESCryptoServiceProvider()
            des.Mode = CipherMode.ECB
            des.Padding = PaddingMode.None
            des.Key() = UTF8Encoding.UTF8.GetBytes("abcdEFGH")
            Dim desdecrypt As ICryptoTransform = des.CreateDecryptor(des.Key(), des.IV)
            Dim memoryStream As MemoryStream = New MemoryStream(rawData)
            Dim cryptostreamDecr As New CryptoStream(_
                memoryStream, desdecrypt, CryptoStreamMode.Write)
            cryptostreamDecr.Write(rawData, 0, rawData.Length)
            Dim retrunImage As Image = Image.FromStream(memoryStream)
            retrunImage.Save("C:\\Sudhakar.jpg")
            cryptostreamDecr.Close()
            Return "C:\\Sudhakar.jpg"
        Catch ex As Exception
            MessageBox.Show("Error Occured")
            Return ex.Message
        End Try
    End Function
    Public Shared Sub main()
        Dim obj As New Decryption
        Console.WriteLine("Testing")
        Dim DecryptedSignaturePath As String = obj.DecryptImage()
        Console.WriteLine("Testing Completed")
    End Sub
End Class

Create an object and call the DecryptImage() function. It returns the path:

Dim obj As New Decryption

Console.WriteLine("Testing")

Dim DecryptedSignaturePath As String = obj.DecryptImage()

Console.WriteLine("Testing Completed")

Here is the sample encrypted string that I get from the database by quering.

Aco5uskB95t+3JeNiJSjTNzdDpGH33M9dOx68XhaWPmU5jHvNKmBLK/wDUmBSHFU5hjbxWGqqRmu

DRs8uuwQCVxPxSqFRJBixdxTuDYx+ZhMUrccGeAa3ZV3vBFw4+hhfIGq4sHVxxd1+rZ30JpslPA9

knGDp0sH8D2ScYOnSwfwPZJxg6dLB/A9knGDp0sH8D2ScYOnSwfeAdHMoABGTfy4KqYjWI1bdqGg

ff7OX+vnQUjALz12Yw8NcvFkhwZ3KbvrY7HeJeOlbQfy1GgRguoKLfQHpwNNXYQ03VGd+TNvpz2K

G5W+a2EINIKLJa9GaREA57aSlZ9MO1BzlbdhyJ1xQ6hU/nnZT2aOqV8pXM23EkiEvCx08rDMyH8V

UMbhF61N5FPhiB+9FstMxnljjvFCN+BwPhRypngb0m4C0kbLV13ibdY7wqQnjL6IaWHo212ZHiCU

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