VB2008和Android之間的加密/解密

Question

我使用這些代碼來加密vb2008中的任何純文本。
我想在我的應用程序在android中解密和使用生成的文件。 我知道把文件放在資產文件夾中，我使用它。
此代碼使用加密來加密。 我如何解密我的android應用程序中生成的文件。 以及我如何在我的Android應用程序中使用它們。 有什麼想法？

Imports System.Security.Cryptography 

Public NotInheritable Class Simple3Des 

    Private TripleDes As New TripleDESCryptoServiceProvider 

    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 

    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 

    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 

    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 

    End Class 

，並在我的表單類

Sub TestEncoding() 
     Dim plainText As String = InputBox("Enter the plain text:") 
     Dim password As String = InputBox("Enter the password:") 

     Dim wrapper As New Simple3Des(password) 
     Dim cipherText As String = wrapper.EncryptData(plainText) 

     MsgBox("The cipher text is: " & cipherText) 
     My.Computer.FileSystem.WriteAllText(My.Computer.FileSystem.SpecialDirectories.Desktop & "\cipherText.txt", cipherText, False) 
    End Sub 

Answer 1

這不是具體到Android，你需要使用Java API的JCE翻譯你的代碼。基本上你會

1. 使用MessageDigest.getInstance("SHA1")獲得SHA1實現
2. 散列你的密碼，以獲得密鑰字節和IV
3. 使用類似Cipher.getInstance("3DES/CBC/PKCS5Padding")獲得3DES實現
4. 初始化加密的密碼使用密鑰和IV使用Cipher.init()
5. 加密數據使用Cipher.doFinal()

您需要確保獲得與VB中相同的密鑰和IV，然後繼續進行加密。你似乎正在哈希一個空字符串來獲得在.NET中的IV，不知道是什麼給你。另請檢查.NET文檔以檢查TripleDESCryptoServiceProvider的默認填充是什麼。