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