VBA AES CBC加密 [英] VBA AES CBC encryption

问题描述

我在 https://github.com/susam/aes.vbs和下面是我最终得到的代码

I have referred encryption in https://github.com/susam/aes.vbs and below is the code i endup with

Function Min(a, b)
    Min = a
    If b < a Then Min = b
End Function

Function B64Encode(bytes)
    Dim result As String
    Dim b64Block() As Byte
    Dim b64Enc As Object
    Dim utf8 As Object
    Dim Offset, Length, BlockSize As Integer
    
    Set b64Enc = CreateObject("System.Security.Cryptography.ToBase64Transform")
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    BlockSize = b64Enc.InputBlockSize
    For Offset = 0 To LenB(bytes) - 1 Step BlockSize
        Length = Min(BlockSize, UBound(bytes) - Offset)
        b64Block = b64Enc.TransformFinalBlock((bytes), Offset, Length)
        result = result & utf8.GetString((b64Block))
    Next
    B64Encode = result
End Function

Function B64Decode(b64Str)
    Dim utf8 As Object
    Dim bytes() As Byte
    Dim b64Dec As Object
    
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    Set b64Dec = CreateObject("System.Security.Cryptography.FromBase64Transform")
    bytes = utf8.GetBytes_4(b64Str)
    B64Decode = b64Dec.TransformFinalBlock((bytes), 0, UBound(bytes))
End Function

Function Encrypt(plaintext, aesKey)
    Dim cipherBytes, aesKeyBytes, ivKeyBytes, plainBytes() As Byte
    
    Dim utf8, AES, aesEnc As Object
    Dim aesIV() As Byte
    Set AES = CreateObject("System.Security.Cryptography.RijndaelManaged")
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    'Set cipherMode = GetObject("System.Security.Cryptography.CipherMode")
    AES.KeySize = 256
    AES.Mode = 1
    AES.Key = CreateObject("System.Text.UTF8Encoding").GetBytes_4("V$ry300DP3r$0NM3")
    AES.IV = CreateObject("System.Text.UTF8Encoding").GetBytes_4("HR$2pIjHR$2pIjPa")
    plainBytes = utf8.GetBytes_4(plaintext)
    'Set aesEnc = AES.CreateEncryptor_2((aesKeyBytes), (ivKeyBytes))
    cipherBytes = AES.TransformFinalBlock((plainBytes), 0, UBound(plainBytes))
        
    Encrypt = B64Encode(cipherBytes)
End Function

现在上面的代码是说指定的初始化向量(iv)与该算法的块大小不匹配"

Now the above code is saying me "specified initialization vector (iv) does not match the block size for this algorithm"

我们不能将IV设置为动态吗?

Cant we set IV dynamic?

推荐答案

Function Min(a, b)
    Min = a
    If b < a Then Min = b
End Function

Function B64Encode(bytes)
    Dim result As String
    Dim b64Block() As Byte
    Dim b64Enc As Object
    Dim utf8 As Object
    Dim Offset, Length, BlockSize As Integer
    
    Set b64Enc = CreateObject("System.Security.Cryptography.ToBase64Transform")
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    BlockSize = b64Enc.InputBlockSize
    For Offset = 0 To LenB(bytes) - 1 Step BlockSize
        Length = Min(BlockSize, UBound(bytes) - Offset)
        b64Block = b64Enc.TransformFinalBlock((bytes), Offset, Length)
        result = result & utf8.GetString((b64Block))
    Next
    B64Encode = result
End Function

Function B64Decode(b64Str)
    Dim utf8 As Object
    Dim bytes() As Byte
    Dim b64Dec As Object
    
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    Set b64Dec = CreateObject("System.Security.Cryptography.FromBase64Transform")
    bytes = utf8.GetBytes_4(b64Str)
    B64Decode = b64Dec.TransformFinalBlock((bytes), 0, UBound(bytes))
End Function


Function Encrypt(plaintext, aesKey)
    Dim cipherBytes, aesKeyBytes, ivKeyBytes, plainBytes() As Byte
    
    Dim utf8, AES, aesEnc, cipherMode As Object
    Dim aesIV() As Byte
        
    Set AES = CreateObject("System.Security.Cryptography.RijndaelManaged")
    Set utf8 = CreateObject("System.Text.UTF8Encoding")
    'Set cipherMode = CreateObject("System.Security.Cryptography.CipherMode")
    
    AES.KeySize = 256
    AES.BlockSize = 256
    'CipherMode.CBC
    AES.Mode = 1
    'PaddingMode.PKCS7
    AES.Padding = 2
    AES.Key = CreateObject("System.Text.UTF8Encoding").GetBytes_4("ThirtyTwoBytes3$ThirtyTwoBytes3$")
    AES.IV = CreateObject("System.Text.UTF8Encoding").GetBytes_4("3$ThreeTwoBytes3$ThreeTwoBytes3$")
    'plainBytes = utf8.GetBytes_4(plaintext)
    plainBytes = B64Decode(plaintext)
    'Set aesEnc = AES.CreateEncryptor_2((aesKeyBytes), (ivKeyBytes))
    cipherBytes = AES.CreateEncryptor().TransformFinalBlock((plainBytes), 0, UBound(plainBytes))
        
    Encrypt = B64Encode(cipherBytes)
End Function

Sub encrypt_hell()
Debug.Print Encrypt("Hello", "PattamuthuArumug")
End Sub

我正在使用256位AES CBC，因此必须使用32个字节的密钥和IV

I am using AES CBC 256 bits so 32 bytes Key and IV has to be used

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