前些日子不少人都要挂QQ,有客户需求就自然有人去研究,所以不少人开始研究QQ的协议.其中最重要的一步就是研究QQ使用的加密算法---TEA算法
关于TEA算法的描述以及C语言源码这里就不多说了,现在给出该算法的VB实现
' ----------------------------------------------------------------------------------
' | |
' | 标准TEA加密解密模块 |
' | Zeffy 制作 |
' | QQ:8481862 |
' | Email:Zephyrmage@163.com |
' | |
' | 2005.8.16 |
' | |
' ----------------------------------------------------------------------------------
Private Const OFFSET_4 = 4294967296# '&h100000000 的数值
Private Const MAXINT_4 = 2147483647 '整型数据所能表示的最大正数值 (&h7fffffff)
Private Const Bit_32 = 2147483648# '&h80000000 的正整数形式
Private Const DELTA = &H9E3779B9 'TEA算法的DELTA值
Private Function AddLong(lX As Long, lY As Long) As Long '长整数加法函数
Dim lX4 As Long
Dim lY4 As Long
Dim lX8 As Long
Dim lY8 As Long
Dim lResult As Long
lX8 = lX And &H80000000
lY8 = lY And &H80000000
lX4 = lX And &H40000000
lY4 = lY And &H40000000
lResult = (lX And &H3FFFFFFF) + (lY And &H3FFFFFFF)
If lX4 And lY4 Then
lResult = lResult Xor &H80000000 Xor lX8 Xor lY8
ElseIf lX4 Or lY4 Then
If lResult And &H40000000 Then
lResult = lResult Xor &HC0000000 Xor lX8 Xor lY8
Else
lResult = lResult Xor &H40000000 Xor lX8 Xor lY8
End If
Else
lResult = lResult Xor lX8 Xor lY8
End If
AddLong = lResult
End Function
Private Function SubtractLong(lX As Long, lY As Long) As Long '长整数减法函数
Dim lX8 As Long
Dim lY8 As Long
Dim mX As Double
Dim mY As Double
Dim mResult As Double
Dim lResult As Long
lX8 = lX And &H80000000
lY8 = lY And &H80000000
mX = lX And &H7FFFFFFF
mY = lY And &H7FFFFFFF
If lX8 Then
If lY8 Then
mResult = mX - mY
Else
mX = mX + Bit_32
mResult = mX - mY
End If
Else
If lY8 Then
mY = lY
mResult = mX - mY
Else
mResult = mX - mY
End If
End If
If mResult < 0 Then
lResult = ((Bit_32 + mResult) Or &H80000000) And &HFFFFFFFF
ElseIf mResult > MAXINT_4 Then
lResult = ((mResult - Bit_32) Or &H80000000) And &HFFFFFFFF
Else
lResult = mResult And &HFFFFFFFF
End If
SubtractLong = lResult
End Function
Private Function LeftRotateLong(lValue As Long, lBits As Integer) As Long '按位左移函数
Dim lngSign As Long, intI As Integer
Dim mValue As Long
lBits = lBits Mod 32
mValue = lValue
If lBits = 0 Then LeftRotateLong = mValue: Exit Function
For intI = 1 To lBits
lngSign = mValue And &H40000000
mValue = (mValue And &H3FFFFFFF) * 2
If lngSign And &H40000000 Then
mValue = mValue Or &H80000000
End If
Next
LeftRotateLong = mValue
End Function
Private Function RightRotateLong(lValue As Long, lBits As Integer) As Long '按位右移函数
Dim lngSign As Long, intI As Integer
Dim mValue As Long
mValue = lValue
lBits = lBits Mod 32
If lBits = 0 Then RightRotateLong = mValue: Exit Function
For intI = 1 To lBits
lngSign = mValue And &H80000000
mValue = (mValue And &H7FFFFFFF) \ 2
If lngSign Then
mValue = mValue Or &H40000000
End If
Next
RightRotateLong = mValue
End Function
Public Sub TeaEncode(v() As Long, k() As Long, lType As Integer) '标准的TEA加密过程,参数lType 为1时表示16轮迭代(QQ使用的就是16轮迭代),否则为32轮迭代
Dim Y As Long, Z As Long
Dim K1 As Long, K2 As Long, K3 As Long, K4 As Long
Dim L1 As Long, L2 As Long, L3 As Long, L4 As Long
Dim Sum As Long
Dim i As Integer, Rounds As Integer
Dim mResult(0 To 1) As Long
Y = v(0)
Z = v(1)
K1 = k(0)
K2 = k(1)
K3 = k(2)
K4 = k(3)
If lType = 1 Then
Rounds = 16
Else
Rounds = 32
End If
For i = 1 To Rounds
'sum += delta ;
Sum = AddLong(Sum, DELTA)
'y += (z<<4)+k[0] ^ z+sum ^ (z>>5)+k[1]
L1 = LeftRotateLong(Z, 4)
L1 = AddLong(L1, K1)
L2 = AddLong(Z, Sum)
L3 = RightRotateLong(Z, 5)
L3 = AddLong(L3, K2)
L4 = L1 Xor L2 Xor L3
Y = AddLong(Y, L4)
'z += (y<<4)+k[2] ^ y+sum ^ (y>>5)+k[3]
L1 = LeftRotateLong(Y, 4)
L1 = AddLong(L1, K3)
L2 = AddLong(Y, Sum)
L3 = RightRotateLong(Y, 5)
L3 = AddLong(L3, K4)
L4 = L1 Xor L2 Xor L3
Z = AddLong(Z, L4)
Next
v(0) = Y
v(1) = Z
End Sub
Public Sub TeaDecode(v() As Long, k() As Long, lType As Integer) '标准TEA解密过程,参数lType 为1时表示16轮迭代(QQ使用的就是16轮迭代),否则为32轮迭代
Dim Y As Long, Z As Long
Dim K1 As Long, K2 As Long, K3 As Long, K4 As Long
Dim L1 As Long, L2 As Long, L3 As Long, L4 As Long
Dim Sum As Long
Dim i As Integer, Rounds As Integer
Dim mResult(0 To 1) As Long
Y = v(0)
Z = v(1)
K1 = k(0)
K2 = k(1)
K3 = k(2)
K4 = k(3)
If lType = 1 Then
Rounds = 16
Sum = LeftRotateLong(DELTA, 4)
Else
Rounds = 32
Sum = LeftRotateLong(DELTA, 5)
End If
For i = 1 To Rounds
L1 = LeftRotateLong(Y, 4)
L1 = AddLong(L1, K3)
L2 = AddLong(Y, Sum)
L3 = RightRotateLong(Y, 5)
L3 = AddLong(L3, K4)
L4 = L1 Xor L2 Xor L3
Z = SubtractLong(Z, L4)
L1 = LeftRotateLong(Z, 4)
L1 = AddLong(L1, K1)
L2 = AddLong(Z, Sum)
L3 = RightRotateLong(Z, 5)
L3 = AddLong(L3, K2)
L4 = L1 Xor L2 Xor L3
Y = SubtractLong(Y, L4)
Sum = SubtractLong(Sum, DELTA)
Next
v(0) = Y
v(1) = Z
End Sub
