vb.net AES CBC加密模式问题

2014-03-09 08:06:29 293 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

VB6/VB.NET实现AES加密：COM互操作与原生加密实战指南 AES（高级加密标准）作为当前主流的对称加密算法，通过分组密码和多重加密轮次确保数据安全，其高效性和强安全性使其成为保护敏感信息的核心技术。在工程实践中，AES广泛应用于数据库连接字符串加密、配置文件保护和网络数据传输等场景。对于Visual Basic开发者而言，在VB6等传统环境中实现AES常面临原生支持不足的挑战，而通过COM互操作技术调用.NET的System.Security.Cryptography命名空间，成为连接遗留系统与现代加密标准的关键桥梁。本文聚焦于VB6与VB.NET环境下的AES实阅读详情

我在vb.net中使用AES的CBC模式加密文本，如256位加密AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA得到

F4EF70150E5C5E23EE2D4D88B57EE14CF004464973EB9A15B8E0A260A469A2040E0281344599B9F9C4D0210ECB1ABA13C701F3F527FF052119113E49D97962C8AA52E48E9E556FC600A56A5E0D119295

修改其中一位比如这样

E4EF70150E5C5E23EE2D4D88B57EE14CF004464973EB9A15B8E0A260A469A2040E0281344599B9F9C4D0210ECB1ABA13C701F3F527FF052119113E49D97962C8AA52E48E9E556FC600A56A5E0D119295

以原密码解密
得到

抝ى寽ꄮ൛ͣ䧲姓QAAAAAAAAAAAAAAAAAAAAAAAA（希望论坛认得乱码）
但是CBC模式不应该是一位出错会导致全部出错的吗

这是我的代码（对密码混乱的处理方式就不要看了。。）
Private Sub cmdEntext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdEntext.Click
If txtpassword.Text = txtconfirm.Text Then
txtd.Text = Encrypttext(txts.Text, txtconfirm.Text, Val(Microsoft.VisualBasic.Left(howmanybits.Text, 3)))
Else
MsgBox("两次密码不一致！", MsgBoxStyle.Critical, "提示")
End If
End Sub

Public Function Encrypttext(ByVal plaintext As String, ByVal sKey As String, ByVal keysize As Integer) As String
On Error Resume Next
Dim AES As New RijndaelManaged()
Dim sha384 As New SHA384CryptoServiceProvider
Dim sha256 As New SHA256CryptoServiceProvider
Dim sha512 As New SHA512CryptoServiceProvider
Dim MD5 As New MD5CryptoServiceProvider
If keysize = 128 Then AES.KeySize = 128 : AES.Key = gethalf(sha256.ComputeHash(Encoding.Unicode.GetBytes(sKey)))
If keysize = 192 Then AES.KeySize = 192 : AES.Key = gethalf(sha384.ComputeHash(Encoding.Unicode.GetBytes(sKey)))
If keysize = 256 Then AES.KeySize = 256 : AES.Key = gethalf(sha512.ComputeHash(Encoding.Unicode.GetBytes(sKey)))
AES.Padding = PaddingMode.PKCS7
AES.IV = MD5.ComputeHash(Encoding.Unicode.GetBytes("By Bz"))
AES.Mode = CipherMode.CBC
Dim desencrypt As ICryptoTransform = AES.CreateEncryptor()
Dim ms As New MemoryStream
Dim cryptostream As New CryptoStream(ms, desencrypt, CryptoStreamMode.Write)
Dim plaintextdata As Byte() = Encoding.Unicode.GetBytes(plaintext)
cryptostream.Write(plaintextdata, 0, plaintextdata.Length)
cryptostream.FlushFinalBlock()
Return Replace(BitConverter.ToString(ms.ToArray()), "-", "")
cryptostream.Close()
ms.Close()
Form1.cmdEntext.Enabled = True
Form1.cmdDetext.Enabled = True
End Function

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