[VB6/VBA] Simple AES 256-bit password protected encryption

@Wqweto; Can you share the binary read and write codes: ReadBinaryFile and WriteBinaryFile?

baData = ReadBinaryFile("c:\path\to\input.file")
AesCryptArray baData, ToUtf8Array("pass")
WriteBinaryFile "c:\path\to\encrypted.file", baData

Here you go

Code:

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'--- mdBinaryFile.bas
Option Explicit

#Const HasPtrSafe = (VBA7 <> 0) Or (TWINBASIC <> 0)

#If HasPtrSafe Then
Private Declare PtrSafe Function DeleteFile Lib "kernel32" Alias "DeleteFileA" (ByVal lpFileName As String) As Long
#Else
Private Declare Function DeleteFile Lib "kernel32" Alias "DeleteFileA" (ByVal lpFileName As String) As Long
#End If

Public Function ReadBinaryFile(sFile As String) As Byte()
    Dim baBuffer()      As Byte
    Dim nFile          As Integer

    On Error GoTo EH
    baBuffer = vbNullString
    nFile = FreeFile
    Open sFile For Binary Access Read Shared As nFile
    If LOF(nFile) > 0 Then
        ReDim baBuffer(0 To LOF(nFile) - 1) As Byte
        Get nFile, , baBuffer
    End If
    Close nFile
    ReadBinaryFile = baBuffer
EH:
End Function

Public Sub WriteBinaryFile(sFile As String, baBuffer() As Byte)
    Dim nFile          As Integer
   
    Call DeleteFile(sFile)
    nFile = FreeFile
    Open sFile For Binary Access Write Shared As nFile
    If UBound(baBuffer) >= 0 Then
        Put nFile, , baBuffer
    End If
    Close nFile
End Sub

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Can be used like this

Code:

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Private Sub TestBinary()
    Const IN_FILE As String = "D:\TEMP\aaa.txt"
    Dim baData() As Byte
   
    baData = ReadBinaryFile(IN_FILE)
    AesCryptArray baData, ToUtf8Array("pass")
    WriteBinaryFile IN_FILE & ".encrypted", baData
   
    baData = ReadBinaryFile(IN_FILE & ".encrypted")
    AesCryptArray baData, ToUtf8Array("pass")
    WriteBinaryFile IN_FILE & ".decrypted", baData
End Sub

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Btw, just updated the the mdAesCtr.bas with some small fixes.

cheers,
</wqw>

Hi wqweto
thanks for the excellent work and for sharing the code
cheers
Tiz

Quote:

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Originally Posted by labmany

Updated the PHP code a bit!

Code:

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<?php

function AesEncryptString($text, $password)
{...}

function AesDecryptString($encr, $password)
{......}

?>

---

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Thanks wqweto, as usual, for excelent code.
Can php code be use to create stored procedure for AES 256 Encryption and Decryption in MS SQL Server 2008? Can someone share?

Quote:

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Originally Posted by cliv

Thanks wqweto, as usual, for excelent code.
Can php code be use to create stored procedure for AES 256 Encryption and Decryption in MS SQL Server 2008? Can someone share?

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Unfortunately MSSQL does not support creating/importing symmetric keys with prepared values for keys and IVs. It uses some weird scheme with KEY_SOURCE strings which is probably PBKDF2 based but not documented.

In recent SQL 2022 there are BACKUP/RESTORE ASYMMETRIC KEY statements but it's not clear what the format of these backup files is and I'm not sure whether using .pfx containers is a possibility here.

Edit: On second glance, there is no backup/restore for *symmetric* keys needed for AES so even these new statements (in .pfx format) cannot help.

cheers,
</wqw>

Quote:

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Originally Posted by wqweto

Unfortunately MSSQL does not support creating/importing symmetric keys with prepared values for keys and IVs. It uses some weird scheme with KEY_SOURCE strings which is probably PBKDF2 based but not documented.
In recent SQL 2022 there are BACKUP/RESTORE ASYMMETRIC KEY statements but it's not clear what the format of these backup files is and I'm not sure whether using .pfx containers is a possibility here.

cheers,
</wqw>

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Thanks for the clarification