Private Declare PtrSafe Function CryptAcquireContext Lib "advapi32.dll" Alias "CryptAcquireContextA" (ByRef phProv As LongPtr, ByVal pszContainer As String, ByVal pszProvider As String, ByVal dwProvType As Long, ByVal dwFlags As Long) As Long
Private Declare PtrSafe Function CryptCreateHash Lib "advapi32.dll" (ByVal hProv As LongPtr, ByVal Algid As Long, ByVal hKey As LongPtr, ByVal dwFlags As Long, ByRef phHash As LongPtr) As Long
Private Declare PtrSafe Function CryptHashData Lib "advapi32.dll" (ByVal hHash As LongPtr, ByVal pbData As String, ByVal dwDataLen As Long, ByVal dwFlags As Long) As Long
Private Declare PtrSafe Function CryptGetHashParam Lib "advapi32.dll" (ByVal hHash As LongPtr, ByVal dwParam As Long, pbData As Any, pdwDataLen As Long, ByVal dwFlags As Long) As Long
Private Declare PtrSafe Function CryptDestroyHash Lib "advapi32.dll" (ByVal hHash As LongPtr) As Long
Private Declare PtrSafe Function CryptReleaseContext Lib "advapi32.dll" (ByVal hProv As LongPtr, ByVal dwFlags As Long) As Long

Private Const PROV_RSA_FULL As Long = 1
Private Const ALG_CLASS_HASH As Long = 4 * 2 ^ 13
Private Const ALG_TYPE_ANY As Long = 0
Private Const ALG_SID_MD5 As Long = 3
Private Const ALGID_MD5 As Long = (ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD5)
Private Const HP_HASHVAL As Long = 2

Public Function MD5(ByVal s As String) As String
    Dim hProv As LongPtr
    Dim hHash As LongPtr
    Dim b() As Byte
    Dim l As Long
    Dim i As Long

    If CryptAcquireContext(hProv, vbNullString, vbNullString, PROV_RSA_FULL, 0) = 0 Then
        Err.Raise Err.LastDllError, , "CryptAcquireContext failed"
    End If

    If CryptCreateHash(hProv, ALGID_MD5, 0, 0, hHash) = 0 Then
        Err.Raise Err.LastDllError, , "CryptCreateHash failed"
    End If

    If CryptHashData(hHash, s, Len(s), 0) = 0 Then
        Err.Raise Err.LastDllError, , "CryptHashData failed"
    End If

    l = 16
    ReDim b(0 To l - 1)
    If CryptGetHashParam(hHash, HP_HASHVAL, b(0), l, 0) = 0 Then
        Err.Raise Err.LastDllError, , "CryptGetHashParam failed"
    End If

    MD5 = ""
    For i = 0 To l - 1
        MD5 = MD5 & Right$("0" & Hex(b(i)), 2)
    Next

    CryptDestroyHash hHash
    CryptReleaseContext hProv, 0
End Function