.NET用AES和128位初始化向量加密XML流

Question

我在一个项目中工作，在这个项目中，我通过XML流向web服务发帖。在这种情况下，提供程序请求使用密码块链接(CBC)模式下的高级加密标准(AES)和128位初始化向量对路由xml进行加密。我是用VB.NET编码的，从我可以看出我已经满足了他们所有的加密要求，但当我提交帖子时，我总是得到一个“无效的路由输入加密”的错误响应。我没有做很多与加密，所以我希望有人与一些加密经验可以帮助我在这里。它失败是因为我没有正确地给IV加前缀吗？在AES中是否有一种将IV合并到密码数据的标准方法？还是加密本身有问题？我在这里呆了一段时间，尝试了几种不同的加密方法，但都没有成功。下面列出的是我的代码和加密要求的摘要。

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使用高级加密标准(AES)在密码块链(CBC)模式下使用128位初始化向量[AES]算法生成对称密钥。不要使用零字节初始化向量。

使用AES对称密钥加密有效的路由输入xml文档。在得到的密码文本前缀128位初始化向量。（建议不要使用全部为0字节的初始化向量。）

Base64对初始化向量和加密的路由输入xml文档进行编码。

使用base64编码的初始化向量和加密的路由输入xml文档构建ENCRYPTED_RI xml元素。

为明文路由输入xml文档生成SHA1哈希。

使用公钥和RSA版本1.5算法[RFC 2437]加密连接的结果。

Base64对加密的级联结果进行编码。

使用base64编码的加密连接结果构建ENCRYPTED_KEY xml元素。

Sub CreateEncryptionXML()
    '############
    '## CREATE AES KEY AND IV
    '############
    Dim SymKey() As Byte
    Dim IV() As Byte
    Dim aes As New AesCryptoServiceProvider

    Using myAes As Aes = System.Security.Cryptography.Aes.Create()
        myAes.KeySize = 128
        myAes.BlockSize = 128
        myAes.Mode = CipherMode.CBC
        myAes.Key = Encoding.UTF8.GetBytes("MyEncryptionKey1")
        myAes.IV = Encoding.UTF8.GetBytes("MyInitialVector1")

        SymKey = myAes.Key
        IV = myAes.IV
    End Using

    '############
    '## ENCRYPT ROUTING INPUT XML DOC
    '############
    Dim riXml As New XmlDocument
    riXml.Load("C:\routingdoc.xml")        
    aes.Key = SymKey
    aes.IV = IV
    aes.Mode = CipherMode.CBC

    ' Convert the plaintext string to a byte array.
    Dim plaintextBytes() As Byte = System.Text.Encoding.UTF8.GetBytes(riXml.OuterXml.ToString())

    ' Create the stream.
    Dim ms As New System.IO.MemoryStream

    ' Create the encoder to write to the stream.
    Dim encStream As New CryptoStream(ms, aes.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()


    '############
    '## PREFIX CIPHER TEXT WITH IV
    '############
    Dim encRiXml() As Byte = ms.ToArray
    Dim arraySize As Integer = IV.Length + encRiXml.Length
    Dim Merged(arraySize) As Byte
    IV.CopyTo(Merged, 0)
    encRiXml.CopyTo(Merged, IV.Length)

    Dim Base64IVEncRiXML As String = Convert.ToBase64String(Merged)

    '******** I BELIVE EVERYTHING PAST HERE IS CORRECT BUT INCLUDED IT TO SHOW WHOLE PROCESS **********

    '############
    '## CREATE SHA1 HASH FOR PLAINTEXT ROUTING INPUT
    '############
    Dim hash() As Byte = New SHA1Managed().ComputeHash(Encoding.UTF8.GetBytes(riXml.OuterXml.ToString()))

    '############
    '## CONCATENATE THE SHA1 HASH OF PLAINTEXT ROUTING INPUT XML WITH AES KEY
    '############
    Dim arraySize2 As Integer = hash.Length + SymKey.Length
    Dim Merged2(arraySize2) As Byte
    hash.CopyTo(Merged2, 0)
    SymKey.CopyTo(Merged2, hash.Length)

    '############
    '## ENCRYPT CONCATENATED RESULT USING RSA
    '############
    Dim EncryptionKey As String = File.ReadAllText("C:\cert-1.txt").Replace("-----BEGIN CERTIFICATE-----" & vbCr & vbLf, "").Replace("-----END CERTIFICATE-----", "")

    TextBox1.Text = EncryptionKey

    Dim binaryCertData() As Byte = Convert.FromBase64String(EncryptionKey)
    Dim cert As X509Certificate2 = New X509Certificate2(binaryCertData)
    Dim xmlKey As String = cert.PublicKey.Key.ToXmlString(False)
    Dim objRSA As RSACryptoServiceProvider = New RSACryptoServiceProvider()
    objRSA.FromXmlString(xmlKey)

    Dim encrypted() As Byte = objRSA.Encrypt(Merged2, False)

    Dim RSAEncryptedSHA1HashAESKey As String = Convert.ToBase64String(encrypted)

    postStaticTest(RSAEncryptedSHA1HashAESKey, Base64IVEncRiXML)
End Sub

'PROVIDED SAMPLE OF XML OUTPUT FROM DOCUMENTATION
'<?xml version="1.0" encoding="UTF-8"?>
'<SECURE_REQUEST_GROUP>
'<ENCRYPTED_KEY Algorithm=”http://www.w3.org/2001/04/xmlenc#rsa-1_5” >
'bXcCaS97p8TtGzlgZ9ogRcEAaw1D1OQCpk1AQFfWYE5J2CheNtRBpuME+uB3wSkwjIWftkYxQ5JRTQ3Qhz7LrCM+TOORl2lFFTpVC9zGUP1xndfT6EQONViV0XGJieWCzXNyjO3XpEl7IdntkVKucrDN9gA7wlimUdw4Ya5sn08=
'</ ENCRYPTED_KEY>
'< ENCRYPTED_RI Algorithm=”http://www.w3.org/2001/04/html" target="_blank">xmlenc#aes128-cbc”>
'9BWPkFDt0Ua/2gN9+BDT9XbYHBuadEREIV1EUmvon/jSr0HkndD/9lBo95H3UYD12TL3wmXVSqi7Ak/QqxzmVRDMgw2Wy0Ezdc3eaA9tOE1c49ZcaZpGM23R1BOazTGdky5v2+oBvSj4a+Ry/aJynvzKvxpTYd15IKOOzPsF/n89Oj6XdjA1TTdn2FCEwo6IkPi0D5QK2i1i/pilEyrrSYQ0oWkYc6ON/OQyL/oHlkBXk0zzQd1HBPOde4/3C6ceajUTvqiIlP6dRBHe6DZ3Ps34g7326jg3koh59RYao/0StgpF3wTJaZ/W36nqlpT3aeoLa/5oKh4A7DjHbYCHTw1uYkPXVGLFl6zTpFRw8hGkPfBRZmS5lXnQl6xidqftb+fx61yBj80/FHAlvmUzBsSQZggeXzBjqlVoWudCuGdC5QH1xKBWrm8haS2UIEdK/DH8fC13oFMpS++C7HTc/u9N8iH6qF0GimxYHvhKwdk3iw/hxrw5Bv1/tQjI1snJm9U1HnokDwG5BWZJp8jBuPgJIapc/DQgIEbM+3NMJXoB/ed9PquPFPPlfoo4E13a3PZPYIDImnLkOjvdPMrZ8A==
'</ ENCRYPTED_RI>
'</SECURE_REQUEST_GROUP>

Answer 1

仍然有几个未解决的实现问题（我想我已经通过使用的值明确了哪些问题）。这绝对应该被重构，我这样做是为了说明每个需求是如何被满足的。

Imports System.Security.Cryptography
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography.X509Certificates

Public Class SoAnswer
    Dim keySize As Integer = 128
    Public Function EncryptData() As XDocument
        Dim encoder As UTF8Encoding = New UTF8Encoding()
        'Specifed Root Name in Declaration
        Dim outputDocument As XDocument = New XDocument(New XElement("SECURE_REQUEST_GROUP"))
        outputDocument.Declaration = New XDeclaration("1.0", "utf-8", "true")
        'outputDocument.Root.Name = "Whatever they specify the root of the xml should be"
        Dim riXml As XDocument
        Dim file As FileStream = New FileStream("C:\routingdoc.xml", FileMode.Open, FileAccess.Read)
        riXml = XDocument.Load(file)

        Dim symKey As Byte() = Requirement1(keySize)
        Dim encryptedXml As Byte() = Requirement2(encoder.GetBytes(riXml.ToString()), symKey)
        Dim encodedXml = Requirement3(encryptedXml)
        'Moved Requirement 4 below requirement 9 so it will appear below the key in the output XML
        'Requirement4(encodedXml, outputDocument)
        Dim hash As Byte() = Requirement5(riXml)
        Dim hashKey = Requirement6(hash, symKey)
        Dim encryptedHashKey = Requirement7(hashKey)
        Dim encodedHashKey = Requirement8(encryptedHashKey)
        Requirement9(encodedHashKey, outputDocument)
        Requirement4(encodedXml, outputDocument)
        'Now you should have an XDocument with the proper content to POST to the web service

        'Decrypt check
        Dim check As String = encoder.GetString(Decrypt(Convert.FromBase64String(encodedXml), symKey))

       postStaticTestXML(outputDocument.ToString)
    End Function

    Private Function Requirement1(size As Integer) As Byte()
        Using aes As New AesCryptoServiceProvider()
            aes.KeySize = size
            aes.GenerateKey()
            Return aes.Key
        End Using
    End Function

    Private Function Requirement2(data() As Byte, key() As Byte) As Byte()
        Using aes As New AesCryptoServiceProvider()
            Dim iv As Byte() = aes.IV
            Using encryptor As ICryptoTransform = aes.CreateEncryptor(key, iv)
                Using msEncrypt As MemoryStream = New MemoryStream()
                    Using csEncrypt As CryptoStream = New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
                        csEncrypt.Write(data, 0, data.Length)
                        csEncrypt.FlushFinalBlock()
                        Dim encryptedData As Byte() = msEncrypt.ToArray()
                        Dim buffer(iv.Length + encryptedData.Length - 1) As Byte
                        buffer = CombineArrays(iv, encryptedData)
                        Return buffer
                    End Using
                End Using
            End Using
        End Using
    End Function

    Private Function Requirement3(content As Byte()) As String
        Return Convert.ToBase64String(content)
    End Function

    Private Sub Requirement4(content As String, ByRef doc As XDocument)
    'added XAttribute to accommodate the required algorithm attribute
        doc.Root.Add(New XElement("ENCRYPTED_RI", content, New XAttribute("Algorithm", "http://www.w3.org/2001/04/xmlenc#aes128-cbc")))
    End Sub

    Private Function Requirement5(content As XDocument) As Byte()
        Dim encoder As UTF8Encoding = New UTF8Encoding()
        Using hash As New SHA1CryptoServiceProvider()
            Return hash.ComputeHash(encoder.GetBytes(content.ToString()))
        End Using
    End Function

    Private Function Requirement6(hash As Byte(), key As Byte()) As Byte()
        Return CombineArrays(hash, key)
    End Function

    Private Function Requirement7(content As Byte()) As Byte()
        'I'm assuming here that they originally sent you a .cer file with their private key in it
        'Dim cert As X509Certificate2 = X509Certificate2.CreateFromCertFile("path\filename of .cer file")
        'X509Certificate2 Could not be directly specified with CreateFromCertFile. A new instance was created and set to derive its value from the retrieved X509Certificate
        Dim cert As X509Certificate2 = New X509Certificate2(X509Certificate.CreateFromCertFile("C:\cert-1.txt"))
        Using rsa As RSACryptoServiceProvider = cert.PublicKey.Key
            'This assumes PKCS7 padding which is most common
            Return rsa.Encrypt(content, False)
        End Using
    End Function

    Private Function Requirement8(content As Byte()) As String
        Return Convert.ToBase64String(content)
    End Function

    Private Sub Requirement9(content As String, ByRef doc As XDocument)
    'Added XAttribute to accommodate for the required "Algorithm" attribute
        doc.Root.Add(New XElement("ENCRYPTED_KEY", content, New XAttribute("Algorithm", "http://www.w3.org/2001/04/xmlenc#rsa-1_5")))
    End Sub

    'Support function
    Private Function CombineArrays(array1 As Byte(), array2 As Byte())
        Dim buffer(array1.Length + array2.Length - 1) as Byte
        System.Buffer.BlockCopy(array1, 0, buffer, 0, array1.Length)
        System.Buffer.BlockCopy(array2, 0, buffer, array1.Length, array2.Length)
        Return buffer
    End Function

    Private Function Decrypt(data() As Byte, key() As Byte) As Byte()
        Dim iv((128 / 8) - 1) As Byte
        Buffer.BlockCopy(data, 0, iv, 0, iv.Length)
        Dim value(data.Length - iv.Length - 1) As Byte
        Buffer.BlockCopy(data, iv.Length, value, 0, value.Length)
        Using aes As AesCryptoServiceProvider = New AesCryptoServiceProvider()
            Using decryptor As ICryptoTransform = aes.CreateDecryptor(key, iv)
                Using msDecrypt As MemoryStream = New MemoryStream(value)
                    Using csDecrypt As CryptoStream = New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
                        Dim decrypted(msDecrypt.Length - 1) As Byte
                        csDecrypt.Read(decrypted, 0, decrypted.Length)
                        Return RemovePadding(decrypted)
                    End Using
                End Using
            End Using
        End Using
    End Function

    Private Function RemovePadding(data As Byte()) As Byte()
        Dim trimCount As Integer = 0
        For i As Integer = data.Length - 1 To data.Length - (128 / 8) + 1 Step -1
            If data(i) = 0 Then trimCount += 1 Else Exit For
        Next

        If trimCount <= 0 Then Return data

        Dim buffer((data.Length - trimCount) - 1) As Byte
        System.Buffer.BlockCopy(data, 0, buffer, 0, buffer.Length)
        Return buffer
    End Function

End Class