VB6 加密解密字符串

Public Function EnCodeStr(ByVal password As String) As String

    Dim il_bit, il_x, il_y, il_z, il_len, i               As Long

    Dim is_out     As String

    il_len = Len(password)

    il_x = 0

    il_y = 0

    is_out = ""

    For i = 1 To il_len

            il_bit = AscW(Mid(password, i, 1))

            il_y = (il_bit * 13 Mod 256) + il_x

            is_out = is_out & ChrW(Fix(il_y))

            il_x = il_bit * 13 / 256

    Next

    is_out = is_out & ChrW(Fix(il_x))

    password = is_out

    il_len = Len(password)

    il_x = 0

    il_y = 0

    is_out = ""

    For i = 1 To il_len

            il_bit = AscW(Mid(password, i, 1))

            il_y = il_bit / 16 + 64

            is_out = is_out & ChrW(Fix(il_y))

            il_y = (il_bit Mod 16) + 64

            is_out = is_out & ChrW(Fix(il_y))

    Next

    EnCodeStr = is_out

End Function

Public Function DeCodeStr(ByVal password As String) As String

    Dim is_out     As String

    Dim il_x, il_y, il_len, i, il_bit             As Long

    il_len = Len(password)

    il_x = 0

    il_y = 0

    is_out = ""

    For i = 1 To il_len Step 2

            il_bit = AscW(Mid(password, i, 1))

            il_y = (il_bit - 64) * 16

            il_y = il_y + AscW(Mid(password, i + 1, 1)) - 64

            is_out = is_out & ChrW(il_y)

    Next

    il_x = 0

    il_y = 0

    password = is_out

    is_out = ""

    il_len = Len(password)

    il_x = AscW(Mid(password, il_len, 1))

    For i = (il_len - 1) To 1 Step -1

            il_y = il_x * 256 + AscW(Mid(password, i, 1))

            il_x = il_y Mod 13

            is_out = ChrW(Fix(il_y / 13)) & is_out

    Next

    DeCodeStr = is_out

End Function