# 经典加密算法在VB中的实现：RC4

2010-03-30

Public Sub main()　　Dim key As String　　For i = 1 To 16　　Randomize　　key = key & Chr(Rnd * 255)　　Next i　　MsgBox RC4(RC4("Welcome To Plindge Studio!", key), key)　　End Sub　　Public Function RC4(inp

Public Sub main()
Dim key As String
For i = 1 To 16
Randomize
key = key & Chr(Rnd * 255)
Next i
MsgBox RC4(RC4("Welcome To Plindge Studio!", key), key)
End Sub
Public Function RC4(inp As String, key As String) As String
Dim S(0 To 255) As Byte, K(0 To 255) As Byte, i As Long
Dim j As Long, temp As Byte, Y As Byte, t As Long, x As Long
Dim Outp As String
For i = 0 To 255
S(i) = i
Next
j = 1
For i = 0 To 255
If j > Len(key) Then j = 1
K(i) = Asc(Mid(key, j, 1))
j = j + 1
Next i
j = 0
For i = 0 To 255
j = (j + S(i) + K(i)) Mod 256
temp = S(i)
S(i) = S(j)
S(j) = temp
Next i
i = 0
j = 0
For x = 1 To Len(inp)
i = (i + 1) Mod 256
j = (j + S(i)) Mod 256
temp = S(i)
S(i) = S(j)
S(j) = temp
t = (S(i) + (S(j) Mod 256)) Mod 256
Y = S(t)
Outp = Outp & Chr(Asc(Mid(inp, x, 1)) Xor Y)
Next
RC4 = Outp
End Function