ASP實現SHA1算法，我的第一個和加解密有關的類.

當初寫這個類可讓我熬了兩晚上的夜，當時對sha1算法一點不懂，完全是翻着密碼學和一個js的範例看一行寫一行。而且asp對位處理支持不好。需要模擬位操作,可折騰死我了. 當時密碼加密大多用的是md5我突發奇想認爲sha1 40位更安全，但網上有找不到asp的代碼，於是就自己加班寫了一個. 現在asp已淘汰，這個代碼用處不大。但這是我和加sha1算法的最早接觸. 裏面很多代碼都是爲了用asp模擬位操作增加的.

<%
'加密解密類
'類方法 SHA1 Byte_Data As String	sha1算法
Class CAMXAM_System_Encrypt_
	Private Array_Power,Array_Bits
	Private ClassName,ClassAuthor,ClassDate
	Private Sub Class_Initialize()
		ClassName = "加密類"
		ClassAuthor = "石卓林"
		ClassDate = "2006年3月23日"
	End Sub
	Private Function Create_Array() '初始化指數數組
		Dim Array_P(30),Array_B(30),Item
		For Item = 0 To 30 Step +1
			Array_P(Item) = Clng(2 ^ Item)
			Array_B(Item) = Clng((2 ^ (Item+1))-1)
		Next
			Array_Power = Array_P
			Array_Bits = Array_B
	End Function
	Private Function LeftShift(Value,Bits)'按位左移
		If Bits < 0 Or Bits > 31 Then
			Err.Raise 6
			Exit Function
		End If
		If Bits = 0 Then
			LeftShift = Value
			Exit Function
		End If
		If Bits = 31 Then
			If Value And 1 Then
					LeftShift = &H80000000
			Else
					LeftShift = 0
			End If
			Exit Function
		End If
			LeftShift = (Value And Array_Bits(31 - Bits)) * Array_Power(Bits)
		If Value And Array_Power(31 - Bits) Then
			LeftShift = ((Value And Array_Bits(30 - Bits)) * Array_Power(Bits)) Or &H80000000
		End If	
	End Function
	Private Function RightShift(Value,Bits)'按位右移
		If Bits < 0 Or Bits > 31 Then
			Err.Raise 6
			Exit Function
		End If
		If Bits = 0 Then
			RightShift = Value
			Exit Function
		End If
		If Bits = 31 Then
			If Value And &H80000000 Then
				RightShift = -1
			Else
				RightShift = 0
			End If
			Exit Function
		End If
			RightShift = (Value And &H7FFFFFFE) \ Array_Power(Bits)
		If Value And &H80000000 Then
			RightShift = Not((Not Value And &H7FFFFFFE) \ Array_Power(Bits) +1)-1
		End If
	End Function
	Private Function NoERightShift(Value,Bits)'無符號右移
		If Bits < 0 Or Bits > 31 Then
			Err.Raise 6
			Exit Function
		End If
		If Bits = 0 Then
			NoERightShift = Value
			Exit Function
		End If
		If Bits = 31 Then
			If Value And &H80000000 Then
				NoERightShift = 1
			Else
				NoERightShift = 0
			End If
			Exit Function
		End If
			NoERightShift = (Value And &H7FFFFFFE) \ Array_Power(Bits)
		If Value And &H80000000 Then
			NoERightShift = NoERightShift Or (&H40000000 \ Array_Power(Bits-1))
		End If
	End Function
	Private Function RotateLeft(Value,Bits)'轉位
		RotateLeft = LeftShift(Value,Bits) Or NoERightShift(Value,(32 - Bits))
	End Function
	Private Function Byte_Array(Byte_Data)'填充和生成數組
		Dim Data_Length,String_Length,Array_Length,Array_Item,Max_Item,Lng_Asc
			String_Length = Len(Byte_Data)
			Data_Length = String_Length * 8
			Array_Length = (((String_Length + 8)\64)+1)*16 -1
		ReDim Data_Array(Array_Length)
		For Array_Item = 0 To Array_Length
			Data_Array(Array_Item) = &H00000000
		Next
		For Array_Item = 0 To String_Length-1
			Max_Item = (Array_Item)\4
			Lng_Asc = AscW(Mid(Byte_Data,Array_Item+1,1))
			Data_Array(Max_Item) = Data_Array(Max_Item) Or LeftShift(Lng_Asc,24-(Array_Item And 3)*8)
		Next
			Data_Array(String_Length\4) = Data_Array(String_Length\4) Or LeftShift(&H80,24-(Array_Item And 3)*8)
			Data_Array(Array_Length) = Data_Length
		Byte_Array = Data_Array
	End Function
	Private Function AddUnsigned(lX, lY)
		Dim lX4
		Dim lY4
		Dim lX8
		Dim lY8
		Dim lResult
	
		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
	
		AddUnsigned = lResult
	End Function
	private function sft(t,b,c,d)
 		if t<20 Then
			sft = (b And c) Or ((Not b) And d)
			Exit Function
		End If
		if t<40 Then
			sft = b Xor c Xor d
			Exit Function
		End If
		if t<60 Then
			sft = (b And c) Or (b And d) Or (c And d)
			Exit Function
		End If
			sft = b Xor c Xor d
	End Function
	Private function skt(t)
		If t < 20 Then
			skt = Clng(1518500249)
		Else
			If t < 40 Then
				skt = Clng(1859775393)
			Else
				if t < 60 Then
				 	skt = Clng(-1894007588)
				Else
					skt = Clng(-899497514)
				End If
			End If
		End If
	End Function
	Private Function getHex(Lng_num)
		Dim Str
			Str = Hex(Lng_num)
		While Len(Str) < 8
			Str = 0 & Str
		Wend
		getHex = Str 
	End Function
	Public Function SHA1(Byte_Data)
		Dim	x,W(79),a,b,c,d,e,i,j,aa,bb,cc,dd,ee,t
			Create_Array
			x = Byte_Array(Byte_Data)
			a = Clng(1732584193)
			b = Clng(-271733879)
			c = Clng(-1732584194)
			d = Clng(271733878)
			e = Clng(-1009589776)
		For i = 0 To UBound(x) Step +16
			aa = a
			bb = b
			cc = c
			dd = d
			ee = e
			For j = 0 To 79 Step +1
				If j < 16 Then
					w(j) = x(i+j)
				Else
					w(j) = RotateLeft(w(j-3) Xor w(j-8) Xor w(j-14) Xor w(j-16),1)
				End If
				t = AddUnsigned(AddUnsigned(RotateLeft(a,5),sft(j,b,c,d)),AddUnsigned(AddUnsigned(e,w(j)),skt(j)))
				e = d
				d = c
				c = RotateLeft(b,30)
				b = a
				a = t
			Next
			a = AddUnsigned(a,aa)
			b = AddUnsigned(b,bb)
			c = AddUnsigned(c,cc)
			d = AddUnsigned(d,dd)
			e = AddUnsigned(e,ee)
		Next
			SHA1 = Lcase(getHex(a) & getHex(b) & getHex(c) & getHex(d) & getHex(e))
	End Function
End Class
%>