PBKDF2 Excel UDF以及如何连接INT（i）

Question

最近我一直在深入研究加密技术，并在Excel中使用散列和加密函数，我可能会在我正在研究的项目中使用它。

我使用简单的哈希函数，例如：

Function Hash(ByVal plainText As String)

    Dim utf8Encoding As Object
    Dim hashManager As Object
    Dim hashBytes() As Byte

    Set utf8Encoding = CreateObject("System.Text.UTF8Encoding")
    Set hashManager = CreateObject("System.Security.Cryptography.SHA512Managed")
    hashBytes = utf8Encoding.GetBytes_4(plainText)
    hashBytes = hashManager.ComputeHash_2(hashBytes)

    Hash = Encode(hashBytes, edHex)

    Set utf8Encoding = Nothing
    Set hashManager = Nothing

End Function

要对结果进行编码，我创建了一个函数：

Function Encode(ByRef arrData() As Byte, ByVal dataType As endecodeDataType) As String

    Dim domDoc As Object
    Set domDoc = CreateObject("MSXML2.DOMDocument")

    With domDoc
        .LoadXML "<root />"
        Select Case dataType
            Case edBase64
                .DocumentElement.dataType = "bin.base64"
            Case edHex
                .DocumentElement.dataType = "bin.hex"
        End Select   
        .DocumentElement.nodeTypedValue = arrData
    End With

    Encode = domDoc.DocumentElement.Text

    Set domDoc = Nothing

End Function

这些结合起来给了我完全可验证的结果。经过更多的研究，我现在正致力于PBKDF2功能：

规格：https://tools.ietf.org/html/rfc2898
测试载体：https://tools.ietf.org/html/rfc6070

我的第一次尝试是如下调查'Rfc2898DeriveBytes'：

Dim hashManager As Object
Set hashManager = CreateObject("System.Security.Cryptography.Rfc2898DeriveBytes")

但是，这会给出一个错误，指出无法创建ActiveX组件。

除了错误，并且为了尝试理解PBKDF2的基础知识，并学习使用位/字节，我创建了以下函数：

编辑：现在我只专注于dkLen <= hLen

Function PBKDF2(ByVal password As String, _
                ByVal hashIterations As Long, _
                ByVal salt As String, _
       Optional ByVal encodeHash As hashEncoding = heBase64) As Variant

    Dim utf8Encoding As Object
    Dim hashManager As Object

    Dim hmacKeyBytes() As Byte
    Dim saltBytes() As Byte

    Dim hmacBytes() As Byte
    Dim tempBytes() As Byte

    Dim i As Long

    'Create encoding and crypto objects
    Set utf8Encoding = CreateObject("System.Text.UTF8Encoding")
    Set hashManager = CreateObject("System.Security.Cryptography.HMACSHA1")

    'Encode the key and salt to bytes
    hmacKeyBytes = utf8Encoding.GetBytes_4(password)
    saltBytes = utf8Encoding.GetBytes_4(salt)

    'Concatenate salt and INT(i) - INT (i) is a four-octet encoding of the integer i, most significant octet first.

    'Set the key in the crypto class
    hashManager.key = hmacKeyBytes

    'Compute HMAC from salt
    hmacBytes = hashManager.ComputeHash_2(saltBytes)
    tempBytes = hmacBytes

    'HMAC iterations
    For i = 1 To hashIterations
        tempBytes = hashManager.ComputeHash_2(tempBytes)
        hmacBytes = XorBytes(tempBytes, hmacBytes)
    Next i

    'ToDo: extract the first dkLen octets to produce a derived key DK

    'Base64, Hex, or Byte() output
    If encodeHash = heBase64 Then
        PBKDF2 = Encode(hmacBytes, edBase64)
    ElseIf encodeHash = heHex Then
        PBKDF2 = Encode(hmacBytes, edHex)
    End If

    Set hashManager = Nothing
    Set utf8Encoding = Nothing

End Function

我将XorBytes定义为：

Function XorBytes(ByRef byte1() As Byte, ByRef byte2() As Byte) As Byte()

    Dim tempBytes() As Byte
    Dim len1 As Long
    Dim i As Long

    len1 = UBound(byte1)
    ReDim tempBytes(len1)

    For i = 0 To len1
        tempBytes(i) = byte1(i) Xor byte2(i)
    Next i

    XorBytes = tempBytes

End Function

我相信我的基础是正确的。我不知道如何解决的一件事是如何将INT（i）连接到salt。规格说明：

U_1 = PRF（P，S || INT（i））

这里，INT（i）是整数i的四个八位字节编码，最重要的是八位字节。

如何在我的VBA代码中实现这一点？我希望这让我更接近这个测试向量：

输入 P =“密码”（8个八位字节） S =“盐”（4个八位字节） c = 1 dkLen = 20
产量 DK = 0c 60 c8 0f 96 1f 0e 71 f3 a9 b5 24 of 60 12 06 2f e0 37 a6（20 octets）