www.pudn.com > Base65Mod.rar > Base65Mod.bas

Attribute VB_Name = "Base65Mod" 
'ʹÓ÷½·¨£ºBase64_Encode(Text1.Text) 
Option Explicit 
 
Private key(1 To 3) As Long 
Private Const base64 = "@bCd3HIFGjKLnMRST0PQUWVxYZABcDefghiJk1Nmoqstpr " + _ 
"uwvXzy567Ol2E894+/" 
 
Private Sub GenKey() 
Dim d As Long, phi As Long, e As Long 
Dim m As Long, X As Long, q As Long 
Dim p As Long 
Randomize 
On Error GoTo top 
top: 
p = Rnd * 1000 \ 1 
If IsPrime(p) = False Then GoTo top 
Sel_q: 
q = Rnd * 1000 \ 1 
If IsPrime(q) = False Then GoTo Sel_q 
n = p * q \ 1 
phi = (p - 1) * (q - 1) \ 1 
d = Rnd * n \ 1 
If d = 0 Or n = 0 Or d = 1 Then GoTo top 
e = Euler(phi, d) 
If e = 0 Or e = 1 Then GoTo top 
 
X = Mult(255, e, n) 
If Not Mult(X, d, n) = 255 Then 
    DoEvents 
    GoTo top 
ElseIf Mult(X, d, n) = 255 Then 
    key(1) = e 
    key(2) = d 
    key(3) = n 
End If 
End Sub 
 
Private Function Euler(ByVal a As Long, ByVal b As Long) As Long 
On Error GoTo error2 
r1 = a: r = b 
p1 = 0: p = 1 
q1 = 2: q = 0 
n = -1 
Do Until r = 0 
    r2 = r1: r1 = r 
    p2 = p1: p1 = p 
    q2 = q1: q1 = q 
    n = n + 1 
    r = r2 Mod r1 
    C = r2 \ r1 
    p = (C * p1) + p2 
    q = (C * q1) + q2 
Loop 
s = (b * p1) - (a * q1) 
If s > 0 Then 
    X = p1 
Else 
    X = (0 - p1) + a 
End If 
Euler = X 
Exit Function 
 
error2: 
Euler = 0 
End Function 
 
Private Function Mult(ByVal X As Long, ByVal p As Long, ByVal m As Long) As Long 
Y = 1 
On Error GoTo error1 
Do While p > 0 
    Do While (p / 2) = (p \ 2) 
        X = (X * X) Mod m 
        p = p / 2 
    Loop 
    Y = (X * Y) Mod m 
    p = p - 1 
Loop 
Mult = Y 
Exit Function 
 
error1: 
Y = 0 
End Function 
 
Private Function IsPrime(lngNumber As Long) As Boolean 
Dim lngCount As Long 
Dim lngSqr As Long 
Dim X As Long 
 
    lngSqr = Sqr(lngNumber) ' get the int square root 
 
    If lngNumber < 2 Then 
        IsPrime = False 
        Exit Function 
    End If 
 
    lngCount = 2 
    IsPrime = True 
 
    If lngNumber Mod lngCount = 0& Then 
        IsPrime = False 
        Exit Function 
    End If 
 
    lngCount = 3 
 
    For X& = lngCount To lngSqr Step 2 
        If lngNumber Mod X& = 0 Then 
            IsPrime = False 
            Exit Function 
        End If 
    Next 
End Function 
 
Function Base65_Encode(DecryptedText As String) As String 
Dim c1, c2, c3 As Integer 
Dim w1 As Integer 
Dim w2 As Integer 
Dim w3 As Integer 
Dim w4 As Integer 
Dim n As Integer 
Dim retry As String 
   For n = 1 To Len(DecryptedText) Step 3 
      c1 = Asc(Mid$(DecryptedText, n, 1)) 
      c2 = Asc(Mid$(DecryptedText, n + 1, 1) + Chr$(0)) 
      c3 = Asc(Mid$(DecryptedText, n + 2, 1) + Chr$(0)) 
      w1 = Int(c1 / 4) 
      w2 = (c1 And 3) * 16 + Int(c2 / 16) 
      If Len(DecryptedText) >= n + 1 Then w3 = (c2 And 15) * 4 + Int(c3 / 64) Else w3 = -1 
      If Len(DecryptedText) >= n + 2 Then w4 = c3 And 63 Else w4 = -1 
 
      retry = retry + mimeencode(w1) + mimeencode(w2) + mimeencode(w3) + mimeencode(w4) 
   Next 
   Base65_Encode = retry 
End Function 
 
Function Base65_Decode(a As String) As String 
Dim w1 As Integer 
Dim w2 As Integer 
Dim w3 As Integer 
Dim w4 As Integer 
Dim n 
Dim retry As String 
 
   For n = 1 To Len(a) Step 4 
      w1 = mimedecode(Mid$(a, n, 1)) 
      w2 = mimedecode(Mid$(a, n + 1, 1)) 
      w3 = mimedecode(Mid$(a, n + 2, 1)) 
      w4 = mimedecode(Mid$(a, n + 3, 1)) 
      If w2 >= 0 Then retry = retry + Chr$(((w1 * 4 + Int(w2 / 16)) And 255)) 
      If w3 >= 0 Then retry = retry + Chr$(((w2 * 16 + Int(w3 / 4)) And 255)) 
      If w4 >= 0 Then retry = retry + Chr$(((w3 * 64 + w4) And 255)) 
   Next n 
   Base65_Decode = retry 
End Function 
 
Private Function mimeencode(w As Integer) As String 
   If w >= 0 Then mimeencode = Mid$(base64, w + 1, 1) Else mimeencode = "" 
End Function 
 
Private Function mimedecode(a As String) As Integer 
   If Len(a) = 0 Then mimedecode = -1: Exit Function 
   mimedecode = InStr(base64, a) - 1 
End Function 
 
Private Function Encode(ByVal Inp As String, ByVal e As Long, ByVal n As Long) As String 
Dim s As String 
s = "" 
m = Inp 
 
If m = "" Then Exit Function 
s = Mult(CLng(Asc(Mid(m, 1, 1))), e, n) 
For I = 2 To Len(m) 
    s = s & "+" & Mult(CLng(Asc(Mid(m, I, 1))), e, n) 
Next I 
Encode = Base65_Encode(s) 
End Function 
 
Private Function Decode(ByVal Inp As String, ByVal d As Long, ByVal n As Long) As String 
St = "" 
ind = Base65_Decode(Inp) 
For I = 1 To Len(ind) 
    nxt = InStr(I, ind, "+") 
    If Not nxt = 0 Then 
        tok = Val(Mid(ind, I, nxt)) 
    Else 
        tok = Val(Mid(ind, I)) 
    End If 
    St = St + Chr(Mult(CLng(tok), d, n)) 
    If Not nxt = 0 Then 
        I = nxt 
    Else 
        I = Len(ind) 
    End If 
Next I 
Decode = St 
End Function