vbc.exe /target:winexe /out:EncryptDecryptApp.exe /r:System.Windows.Forms.dll /r:System.Drawing.dll EncryptDecryptForm.vb
'ファイルの安居化、復号化
Imports System.Security.Cryptography
Imports System.IO
Imports System.Text
Imports System.Windows.Forms
Public Class EncryptDecryptForm
Inherits Form
Private Sub New()
Me.Text = "ファイル暗号化・復号化"
Me.Width = 400
Me.Height = 200
Me.AllowDrop = True
' フォームのドラッグ＆ドロップ設定
AddHandler Me.DragEnter, AddressOf Form_DragEnter
AddHandler Me.DragDrop, AddressOf Form_DragDrop
End Sub
' ファイルがドラッグされたとき
Private Sub Form_DragEnter(sender As Object, e As DragEventArgs)
If e.Data.GetDataPresent(DataFormats.FileDrop) Then
e.Effect = DragDropEffects.Copy
End If
End Sub
' ファイルがドロップされたとき
Private Sub Form_DragDrop(sender As Object, e As DragEventArgs)
Dim files() As String = CType(e.Data.GetData(DataFormats.FileDrop), String())
Dim operation As DialogResult = MessageBox.Show("暗号化しますか？それとも復号化しますか？", "操作を選択", MessageBoxButtons.YesNo)
If operation = DialogResult.Yes Then
' 暗号化処理
For Each file In files
EncryptFile(file, file & ".enc", "password123")
Next
MessageBox.Show("暗号化が完了しました。")
Else
' 復号化処理
For Each file In files
Dim outputFile As String = Path.GetFileNameWithoutExtension(file)
DecryptFile(file, outputFile, "password123")
Next
MessageBox.Show("復号化が完了しました。")
End If
End Sub
' 暗号化メソッド
Private Sub EncryptFile(ByVal inputFile As String, ByVal outputFile As String, ByVal password As String)
Try
Dim AES As New RijndaelManaged
Dim hash_AES As New MD5CryptoServiceProvider
Dim hash As Byte() = hash_AES.ComputeHash(Encoding.UTF8.GetBytes(password))
AES.Key = hash
AES.Mode = CipherMode.CFB
Dim fsInput As New FileStream(inputFile, FileMode.Open)
Dim fsOutput As New FileStream(outputFile, FileMode.Create)
Dim cs As New CryptoStream(fsOutput, AES.CreateEncryptor(), CryptoStreamMode.Write)
Dim buffer(4096) As Byte
Dim read As Integer
Do
read = fsInput.Read(buffer, 0, buffer.Length)
If read > 0 Then
cs.Write(buffer, 0, read)
End If
Loop While read > 0
fsInput.Close()
cs.Close()
fsOutput.Close()
Catch ex As Exception
MessageBox.Show("エラーが発生しました: " & ex.Message)
End Try
End Sub
' 復号化メソッド
Private Sub DecryptFile(ByVal inputFile As String, ByVal outputFile As String, ByVal password As String)
Try
Dim AES As New RijndaelManaged
Dim hash_AES As New MD5CryptoServiceProvider
Dim hash As Byte() = hash_AES.ComputeHash(Encoding.UTF8.GetBytes(password))
AES.Key = hash
AES.Mode = CipherMode.CFB
Dim fsInput As New FileStream(inputFile, FileMode.Open)
Dim fsOutput As New FileStream(outputFile, FileMode.Create)
Dim cs As New CryptoStream(fsInput, AES.CreateDecryptor(), CryptoStreamMode.Read)
Dim buffer(4096) As Byte
Dim read As Integer
Do
read = cs.Read(buffer, 0, buffer.Length)
If read > 0 Then
fsOutput.Write(buffer, 0, read)
End If
Loop While read > 0
fsInput.Close()
cs.Close()
fsOutput.Close()
Catch ex As Exception
MessageBox.Show("エラーが発生しました: " & ex.Message)
End Try
End Sub
' メインメソッド
Public Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New EncryptDecryptForm())
End Sub
End Class