Question

我使用这些代码加密vb2008中的任何纯文本我想解密并在我的Android应用程序中使用生成的文件。我知道把文件放在assets文件夹中我会用它此代码使用加密技术进行加密。我如何解密我的Android应用程序中生成的文件。以及我如何在我的Android应用程序中使用它们。任何的想法？

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

并在我的表单类

中

    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

这不是Android特有的，您需要使用Java JCE API翻译您的代码。基本上你会

使用MessageDigest.getInstance("SHA1")获取SHA1实施
哈希密码以获取密钥字节和IV
使用类似Cipher.getInstance("3DES/CBC/PKCS5Padding")的内容来获取3DES实现
使用密钥和IV使用Cipher.init()
使用Cipher.doFinal()

您需要确保首先获得与VB中相同的密钥和IV，然后继续加密。你似乎要在一个空字符串中进行哈希处理以获得.NET中的IV，不知道它给你带来了什么。另请检查.NET文档以检查TripleDESCryptoServiceProvider的默认填充是什么。

VB2008和Android之间的加密/解密

1 个答案: