如何解决VBA AES CBC加密
我在https://github.com/susam/aes.vbs中提到了加密,下面是我最终得到的代码
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),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$2pIjPa")
plainBytes = utf8.GetBytes_4(plaintext)
'Set aesEnc = AES.CreateEncryptor_2((aesKeyBytes),(ivKeyBytes))
cipherBytes = AES.TransformFinalBlock((plainBytes),UBound(plainBytes))
Encrypt = B64Encode(cipherBytes)
End Function
现在上面的代码告诉我“指定的初始化向量(iv)与该算法的块大小不匹配”
我们不能设置IV动态吗?
解决方法
Function Min(a,b)
Min = a
If b < a Then Min = b
End Function
Function B64Encode(bytes)
Dim result As String
Dim b64Block() As Byte
Dim b64Enc As Object
Dim utf8 As Object
Dim Offset,Length,BlockSize As Integer
Set b64Enc = CreateObject("System.Security.Cryptography.ToBase64Transform")
Set utf8 = CreateObject("System.Text.UTF8Encoding")
BlockSize = b64Enc.InputBlockSize
For Offset = 0 To LenB(bytes) - 1 Step BlockSize
Length = Min(BlockSize,UBound(bytes) - Offset)
b64Block = b64Enc.TransformFinalBlock((bytes),Offset,Length)
result = result & utf8.GetString((b64Block))
Next
B64Encode = result
End Function
Function B64Decode(b64Str)
Dim utf8 As Object
Dim bytes() As Byte
Dim b64Dec As Object
Set utf8 = CreateObject("System.Text.UTF8Encoding")
Set b64Dec = CreateObject("System.Security.Cryptography.FromBase64Transform")
bytes = utf8.GetBytes_4(b64Str)
B64Decode = b64Dec.TransformFinalBlock((bytes),UBound(bytes))
End Function
Function Encrypt(plaintext,aesKey)
Dim cipherBytes,aesKeyBytes,ivKeyBytes,plainBytes() As Byte
Dim utf8,AES,aesEnc,cipherMode As Object
Dim aesIV() As Byte
Set AES = CreateObject("System.Security.Cryptography.RijndaelManaged")
Set utf8 = CreateObject("System.Text.UTF8Encoding")
'Set cipherMode = CreateObject("System.Security.Cryptography.CipherMode")
AES.KeySize = 256
AES.BlockSize = 256
'CipherMode.CBC
AES.Mode = 1
'PaddingMode.PKCS7
AES.Padding = 2
AES.Key = CreateObject("System.Text.UTF8Encoding").GetBytes_4("ThirtyTwoBytes3$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),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
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