initial commit

ArinLogin/EnDec.vb

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+Imports System.Security.Cryptography
+
+Public Class EnDec
+
+
+    Private TripleDes As New TripleDESCryptoServiceProvider
+    Sub New(ByVal key As String)
+        ' Initialize the crypto provider.
+        TripleDes.Key = TruncateHash(key, TripleDes.KeySize \ 8)
+        TripleDes.IV = TruncateHash("", TripleDes.BlockSize \ 8)
+    End Sub
+
+    Private Function TruncateHash( _
+        ByVal key As String, _
+        ByVal length As Integer) _
+        As Byte()
+
+        Dim sha1 As New SHA1CryptoServiceProvider
+
+        ' Hash the key.
+        Dim keyBytes() As Byte = _
+            System.Text.Encoding.Unicode.GetBytes(key)
+        Dim hash() As Byte = sha1.ComputeHash(keyBytes)
+
+        ' Truncate or pad the hash.
+        ReDim Preserve hash(length - 1)
+        Return hash
+    End Function
+
+    ''' <summary>
+    ''' 문자열의 암호화
+    ''' </summary>
+    ''' <param name="plaintext"></param>
+    ''' <returns></returns>
+    ''' <remarks></remarks>
+    Public Function EncryptData( _
+        ByVal plaintext As String) _
+        As String
+
+        ' Convert the plaintext string to a byte array.
+        Dim plaintextBytes() As Byte = _
+            System.Text.Encoding.Unicode.GetBytes(plaintext)
+
+        ' Create the stream.
+        Dim ms As New System.IO.MemoryStream
+        ' Create the encoder to write to the stream.
+        Dim encStream As New CryptoStream(ms, _
+            TripleDes.CreateEncryptor(), _
+            System.Security.Cryptography.CryptoStreamMode.Write)
+
+        ' Use the crypto stream to write the byte array to the stream.
+        encStream.Write(plaintextBytes, 0, plaintextBytes.Length)
+        encStream.FlushFinalBlock()
+
+        ' Convert the encrypted stream to a printable string.
+        Return Convert.ToBase64String(ms.ToArray)
+    End Function
+
+    ''' <summary>
+    ''' 복호화'
+    ''' </summary>
+    ''' <param name="encryptedtext"></param>
+    ''' <returns></returns>
+    ''' <remarks></remarks>
+    Public Function DecryptData( _
+    ByVal encryptedtext As String) _
+    As String
+
+        ' Convert the encrypted text string to a byte array.
+        Dim encryptedBytes() As Byte = Convert.FromBase64String(encryptedtext)
+
+        ' Create the stream.
+        Dim ms As New System.IO.MemoryStream
+        ' Create the decoder to write to the stream.
+        Dim decStream As New CryptoStream(ms, _
+            TripleDes.CreateDecryptor(), _
+            System.Security.Cryptography.CryptoStreamMode.Write)
+
+        ' Use the crypto stream to write the byte array to the stream.
+        decStream.Write(encryptedBytes, 0, encryptedBytes.Length)
+        decStream.FlushFinalBlock()
+
+        ' Convert the plaintext stream to a string.
+        Return System.Text.Encoding.Unicode.GetString(ms.ToArray)
+    End Function
+
+    ''' <summary>
+    ''' 파일로부터 문자열을 읽어옵니다.
+    ''' </summary>
+    ''' <param name="Filename"></param>
+    ''' <remarks></remarks>
+    Public Function Read_STring(ByVal Filename As String) As String
+        Dim cipherText As String = My.Computer.FileSystem.ReadAllText(Filename)
+
+        ' DecryptData throws if the wrong password is used.
+        Try
+            Dim plainText As String = DecryptData(cipherText)
+            Return plainText
+            MsgBox("해독값은? " & plainText)
+        Catch ex As System.Security.Cryptography.CryptographicException
+            Return ""
+            MsgBox("암호화키가 일치하지않거나 기타 오류입니다")
+        End Try
+
+    End Function
+
+    ''' <summary>
+    ''' 파일에 해당 문자열을 기록합니다.
+    ''' </summary>
+    ''' <param name="Filename"></param>
+    ''' <param name="Contents"></param>
+    ''' <remarks></remarks>
+    Public Sub Write_String(ByVal Filename As String, ByVal Contents As String)
+        Dim cipherText As String = EncryptData(Contents)
+
+        MsgBox("암호화된값은? " & cipherText)
+        My.Computer.FileSystem.WriteAllText(Filename, cipherText, False)
+
+    End Sub
+
+
+End Class