開始：
在網絡上，看到有SQL Server 2000和SQL Server 2005 的存儲過程加密和解密的方法，后來分析了其中的代碼，發現它們的原理都是一樣的。后來自己根據實際的應用環境，編寫了兩個存儲過程，一個加密存儲過程（sp_EncryptObject），和一個解密存儲過程（sp_EncryptObject），它們可以應用於SQL Server中的儲過程，函數，視圖，以及觸發器。
感覺這兩個存儲過程蠻有意思的，拿來與大家分享；如果你看過類似的，就當作重溫一下也好。
用於加密的存儲過程 （sp_EncryptObject） ：
存儲過程（sp_EncryptObject）加密的方法是在存儲過程，函數，視圖的“As”位置前加上“with encryption”；如果是觸發器，就在“for”位置前加“with encryption”。
如果觸發器是{ AFTER | INSTEAD OF} 需要修改下面代碼"For"位置：
if objectproperty(object_id(@Object),'ExecIsAfterTrigger')=0 set @Replace='As' ; else set @Replace='For ';
存儲過程完成代碼：
View Code
Use master Go if object_ID('[sp_EncryptObject]') is not null Drop Procedure [sp_EncryptObject] Go create procedure sp_EncryptObject ( @Object sysname='All' ) as /* 當@Object=All的時候，對所有的函數，存儲過程，視圖和觸發器進行加密 調用方法： 1. Execute sp_EncryptObject 'All' 2. Execute sp_EncryptObject 'ObjectName' */ begin set nocount on if @Object <>'All' begin if not exists(select 1 from sys.objects a where a.object_id=object_id(@Object) And a.type in('P','V','TR','FN','IF','TF')) begin --SQL Server 2008 raiserror 50001 N'無效的加密對象！加密對象必須是函數，存儲過程，視圖或觸發器。' --SQL Server 2012 --throw 50001, N'無效的加密對象！加密對象必須是函數，存儲過程，視圖或觸發器。',1 return end if exists(select 1 from sys.sql_modules a where a.object_id=object_id(@Object) and a.definition is null) begin --SQL Server 2008 raiserror 50001 N'對象已經加密！' --SQL Server 2012 --throw 50001, N'對象已經加密！',1 return end end declare @sql nvarchar(max),@C1 nchar(1),@C2 nchar(1),@type nvarchar(50),@Replace nvarchar(50) set @C1=nchar(13) set @C2=nchar(10) declare cur_Object cursor for select object_name(a.object_id) As ObjectName,a.definition from sys.sql_modules a inner join sys.objects b on b.object_id=a.object_id and b.is_ms_shipped=0 and not exists(select 1 from sys.extended_properties x where x.major_id=b.object_id and x.minor_id=0 and x.class=1 and x.name='microsoft_database_tools_support' ) where b.type in('P','V','TR','FN','IF','TF') and (b.name=@Object or @Object='All') and b.name <>'sp_EncryptObject' and a.definition is not null order by Case when b.type ='V' then 1 when b.type ='TR' then 2 when b.type in('FN','IF','TF') then 3 else 4 end,b.create_date,b.object_id open cur_Object fetch next from cur_Object into @Object,@sql while @@fetch_status=0 begin Begin Try if objectproperty(object_id(@Object),'ExecIsAfterTrigger')=0 set @Replace='As' ; else set @Replace='For '; if (patindex('%'+@C1+@C2+@Replace+@C1+@C2+'%',@sql)>0) begin set @sql=Replace(@sql,@C1+@C2+@Replace+@C1+@C2,@C1+@C2+'With Encryption'+@C1+@C2+@Replace+@C1+@C2) end else if(patindex('%'+@C1+@Replace+@C1+'%',@sql)>0) begin set @sql=Replace(@sql,@C1+@Replace+@C1,@C1+'With Encryption'+@C1+@Replace+@C1) end else if(patindex('%'+@C2+@Replace+@C2+'%',@sql)>0) begin set @sql=Replace(@sql,@C2+@Replace+@C2,@C2+'With Encryption'+@C2+@Replace+@C2) end else if(patindex('%'+@C2+@Replace+@C1+'%',@sql)>0) begin set @sql=Replace(@sql,@C2+@Replace+@C1,@C1+'With Encryption'+@C2+@Replace+@C1) end else if(patindex('%'+@C1+@C2+@Replace+'%',@sql)>0) begin set @sql=Replace(@sql,@C1+@C2+@Replace,@C1+@C2+'With Encryption'+@C1+@C2+@Replace) end else if(patindex('%'+@C1+@Replace+'%',@sql)>0) begin set @sql=Replace(@sql,@C1+@Replace,@C1+'With Encryption'+@C1+@Replace) end else if(patindex('%'+@C2+@Replace+'%',@sql)>0) begin set @sql=Replace(@sql,@C2+@Replace,@C2+'With Encryption'+@C2+@Replace) end set @type = case when object_id(@Object,'P')>0 then 'Proc' when object_id(@Object,'V')>0 then 'View' when object_id(@Object,'TR')>0 then 'Trigger' when object_id(@Object,'FN')>0 or object_id(@Object,'IF')>0 or object_id(@Object,'TF')>0 then 'Function' end set @sql=Replace(@sql,'Create '+@type,'Alter '+@type) Begin Transaction exec(@sql) print N'已完成加密對象('+@type+')：'+@Object Commit Transaction End Try Begin Catch Declare @Error nvarchar(2047) Set @Error='Object: '+@Object+@C1+@C2+'Error: '+Error_message() Rollback Transaction print @Error print @sql End Catch fetch next from cur_Object into @Object,@sql end close cur_Object deallocate cur_Object end Go exec sp_ms_marksystemobject 'sp_EncryptObject' --標識為系統對象 go
如果SQL Server 2012，請修改下面兩個位置的代碼。在SQL Server 2012，建議在使用throw來代替raiserror。
解密方法：
解密過程，最重要采用異或方法：
[字符1]經過函數 fn_x（x）加密變成[加密后字符1]，如果我們已知[加密后字符1]，反過來查[字符1],可以這樣：
[字符1] = [字符2] ^ fn_x([字符2]) ^ [加密后字符1]
這里我列舉一個簡單的例子：
--創建加密函數（fn_x） if object_id('fn_x') is not null drop function fn_x go create function fn_x ( @x nchar(1) )returns nchar(1) as begin return(nchar((65535-unicode(@x)))) end go declare @nchar_1_encrypt nchar(1),@nchar_2 nchar(1) --對字符'A'進行加密，存入變量@nchar_1_encrypt set @nchar_1_encrypt=dbo.fn_x(N'A') --參考的字符@nchar_2 set @nchar_2='x' --算出@nchar_1_encrypt 加密前的字符 select nchar(unicode(@nchar_2)^unicode(dbo.fn_x(@nchar_2))^unicode(@nchar_1_encrypt)) as [@nchar_1] /* @nchar_1 -------------------- A */
[注]： 從SQL Server 2000至 SQL Server 2012 采用異或方法都可以解密
用於解密的存儲過程（sp_DecryptObject）：
View Code
Use master Go if object_ID('[sp_DecryptObject]') is not null Drop Procedure [sp_DecryptObject] Go create procedure sp_DecryptObject ( @Object sysname, --要解密的對象名：函數，存儲過程，視圖或觸發器 @MaxLength int=4000 --評估內容的長度 ) as set nocount on /* 1. 解密 */ if not exists(select 1 from sys.objects a where a.object_id=object_id(@Object) And a.type in('P','V','TR','FN','IF','TF')) begin --SQL Server 2008 raiserror 50001 N'無效的對象！要解密的對象必須是函數，存儲過程，視圖或觸發器。' --SQL Server 2012 --throw 50001, N'無效的對象！要解密的對象必須是函數，存儲過程，視圖或觸發器。',1 return end if exists(select 1 from sys.sql_modules a where a.object_id=object_id(@Object) and a.definition is not null) begin --SQL Server 2008 raiserror 50001 N'對象沒有加密！' --SQL Server 2012 --throw 50001, N'無效的對象！要解密的對象必須是函數，存儲過程，視圖或觸發器。',1 return end declare @sql nvarchar(max) --解密出來的SQL語句 ,@imageval nvarchar(max) --加密字符串 ,@tmpStr nvarchar(max) --臨時SQL語句 ,@tmpStr_imageval nvarchar(max) --臨時SQL語句(加密后) ,@type char(2) --對象類型('P','V','TR','FN','IF','TF') ,@objectID int --對象ID ,@i int --While循環使用 ,@Oject1 nvarchar(1000) set @objectID=object_id(@Object) set @type=(select a.type from sys.objects a where a.object_id=@objectID) declare @Space4000 nchar(4000) set @Space4000=replicate('-',4000) /* @tmpStr 會構造下面的SQL語句 ------------------------------------------------------------------------------- alter trigger Tr_Name on Table_Name with encryption for update as return /**/ alter proc Proc_Name with encryption as select 1 as col /**/ alter view View_Name with encryption as select 1 as col /**/ alter function Fn_Name() returns int with encryption as begin return(0) end/**/ */ set @Oject1=quotename(object_schema_name(@objectID))+'.'+quotename(@Object) set @tmpStr= case when @type ='P ' then N'Alter Procedure '+@Oject1+' with encryption as select 1 as column1 ' when @type ='V ' then N'Alter View '+@Oject1+' with encryption as select 1 as column1 ' when @type ='FN' then N'Alter Function '+@Oject1+'() returns int with encryption as begin return(0) end ' when @type ='IF' then N'Alter Function '+@Oject1+'() returns table with encryption as return(Select a.name from sys.types a) ' when @type ='TF' then N'Alter Function '+@Oject1+'() returns @t table(name nvarchar(50)) with encryption as begin return end ' else 'Alter Trigger '+@Oject1+'on '+quotename(object_schema_name(@objectID))+'.'+(select Top(1) quotename(object_name(parent_id)) from sys.triggers a where a.object_id=@objectID)+' with encryption for update as return ' end set @tmpStr=@tmpStr+'/*'+@Space4000 set @i=0 while @i < (ceiling(@MaxLength*1.0/4000)-1) begin set @tmpStr=@tmpStr+ @Space4000 Set @i=@i+1 end set @tmpStr=@tmpStr+'*/' ------------ set @imageval =(select top(1) a.imageval from sys.sysobjvalues a where a.objid=@objectID and a.valclass=1) begin tran exec(@tmpStr) set @tmpStr_imageval =(select top(1) a.imageval from sys.sysobjvalues a where a.objid=@objectID and a.valclass=1) rollback tran ------------- set @tmpStr=stuff(@tmpStr,1,5,'create') set @sql='' set @i=1 while @i<= (datalength(@imageval)/2) begin set @sql=@sql+isnull(nchar(unicode(substring(@tmpStr,@i,1)) ^ unicode(substring(@tmpStr_imageval,@i,1))^unicode(substring(@imageval,@i,1)) ),'') Set @i+=1 end /* 2. 列印 */ declare @patindex int while @sql>'' begin set @patindex=patindex('%'+char(13)+char(10)+'%',@sql) if @patindex >0 begin print substring(@sql,1,@patindex-1) set @sql=stuff(@sql,1,@patindex+1,'') end else begin set @patindex=patindex('%'+char(13)+'%',@sql) if @patindex >0 begin print substring(@sql,1,@patindex-1) set @sql=stuff(@sql,1,@patindex,'') end else begin set @patindex=patindex('%'+char(10)+'%',@sql) if @patindex >0 begin print substring(@sql,1,@patindex-1) set @sql=stuff(@sql,1,@patindex,'') end else begin print @sql set @sql='' end end end end Go exec sp_ms_marksystemobject 'sp_DecryptObject' --標識為系統對象 go
如果SQL Server 2012，請修改下面兩個位置的代碼。方法類似於前面的加密過程：
搭建測試環境：
在一個測試環境中（DB: Test），先執行上面的加密存儲過程（sp_EncryptObject）和解密存儲過程（sp_EncryptObject）;再創建兩個表：TableA & TableB
use test go --創建表: TableA & TableB if object_id('myTableA') is not null drop table myTableA if object_id('myTableB') is not null drop table myTableB go create table myTableA (ID int identity,data nvarchar(50),constraint PK_myTableA primary key(ID)) create table myTableB (ID int ,data nvarchar(50),constraint PK_myTableB primary key(ID)) go
接下來，我們要創建6個未加密的對象（對象類型包含 'P','V','TR','FN','IF','TF'）：
1.視圖（myView）：
View Code
if object_id('myView') is not null drop view myView go create view myView As select * from TableA; go
2.觸發器（MyTrigger）：
View Code
if object_id('MyTrigger') is not null drop Trigger MyTrigger go create trigger MyTrigger on TableA for update As insert into TableB(ID,data) select a.ID,a.Data From Inserted a go
3.存儲過程（MyProc）：
View Code
if object_id('MyProc') is not null drop proc MyProc go create proc MyProc ( @data nvarchar(50) ) As insert into TableA(data) values(@data) go
4.用戶定義表值函數(TF)（MyFunction_TF）：
View Code
if object_id('MyFunction_TF') is not null drop function MyFunction_TF go create function MyFunction_TF ( ) returns @t table ( id int, data nvarchar(50) ) As begin insert @t(id,data) select id,data from TableA return end go
5.內聯表值函數(IF) （MyFunction_IF）：
View Code
if object_id('MyFunction_IF') is not null drop function MyFunction_IF go create function MyFunction_IF ( ) returns table As return(select top(3) id, data from TableA order by id desc) go
6.標量函數(FN)（MyFunction_FN）：
View Code
if object_id('MyFunction_FN') is not null drop function MyFunction_FN go create function MyFunction_FN ( ) returns nvarchar(50) As begin return(select top(1) data from TableA order by id desc) end go
當執行完了上面的1-6步驟的腳本，我們通過查詢系統視圖sys.sql_modules，可以看到未加密前的定義信息：
select b.name as object,b.type,a.definition from sys.sql_modules a inner join sys.objects b on b.object_id=a.object_id where b.create_date>=convert(date,getdate()) order by b.object_id
加密測試：
下面我就通過調用加密存儲過程（sp_EncryptObject），一次性對它們進行加密：
use test go exec sp_EncryptObject 'all' go
當我們再查回系統視圖sys.sql_modules，會發現definition列返回的是null值，說明定義內容已經給加密：
解密測試：
解密過程，必須在DAC連接SQL Server，我們這里例子是從 SSMS(SQL Server Management Studio) 查詢編輯器啟動 DAC，如圖：
解密存儲過程（sp_DecryptObject），只能一次對一個存儲過程、函數、視圖或觸發器，進行解密：
use test go exec sp_DecryptObject MyTrigger go
當定義內容長度超過4000，我們可以指定@MaxLength的值，如：
exec sp_DecryptObject fn_My,20000 go
這里（fn_My）是一個函數，定義內容超過了8000：
... ...
小結：
雖然，上面的腳本，我已經在SQL Server 2008 R2 和SQL Server 2012測試過，但無法避免一些未知錯誤 。如果你自己在測試上面的腳本，請不要在生產環境上。如果你在應用過程，碰到有什么問題或有什么意見和建議可以發email聯系我或跟帖，在此非常感謝！