sql存储过程加密和解密(MSSQL)

在网络上，看到有SQL Server 2000和SQL Server 2005 的存储过程加密和解密的方法，后来分析了其中的代码，发现它们的原理都是一样的。后来自己根据实际的应用环境，编写了两个存储过程，一个加密存储过程（sp_EncryptObject），和一个解密存储过程（sp_EncryptObject），它们可以应用于SQL Server中的储过程，函数，视图，以及触发器。

感觉这两个存储过程蛮有意思的，拿来与大家分享；如果你看过类似的，就当作重温一下也好。

用于加密的存储过程（sp_EncryptObject）：

存储过程（sp_EncryptObject）加密的方法是在存储过程，函数，视图的“As”位置前加上“with encryption”；如果是触发器，就在“for”位置前加“with encryption”。

如果触发器是{ AFTER | INSTEAD OF} 需要修改下面代码"For"位置：

if objectproperty(object_id(@Object),'ExecIsAfterTrigger')=0 set @Replace='As' ; else set @Replace='For ';

存储过程完成代码：

  1 Use master
  2 Go
  3 if object_ID('[sp_EncryptObject]') is not null
  4     Drop Procedure [sp_EncryptObject]
  5 Go
  6 create procedure sp_EncryptObject 
  7 (
  8     @Object sysname='All'
  9 )
 10 as
 11 /*
 12     当@Object=All的时候，对所有的函数，存储过程，视图和触发器进行加密
 13     调用方法：
 14     1. Execute sp_EncryptObject 'All'
 15     2. Execute sp_EncryptObject 'ObjectName'
 16 */
 17 begin
 18     set nocount on
 19     
 20     if @Object <>'All'
 21     begin
 22         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'))
 23         begin
 24             --SQL Server 2008
 25             raiserror 50001 N'无效的加密对象！加密对象必须是函数，存储过程，视图或触发器。'
 26 
 27             --SQL Server 2012
 28             --throw 50001, N'无效的加密对象！加密对象必须是函数，存储过程，视图或触发器。',1  
 29 
 30             return
 31         end
 32         
 33         if exists(select 1 from sys.sql_modules a where a.object_id=object_id(@Object) and a.definition is null)
 34         begin
 35             --SQL Server 2008
 36             raiserror 50001 N'对象已经加密！'
 37 
 38             --SQL Server 2012
 39             --throw 50001, N'对象已经加密！',1  
 40             return
 41         end
 42     end
 43     
 44     declare @sql nvarchar(max),@C1 nchar(1),@C2 nchar(1),@type nvarchar(50),@Replace nvarchar(50)
 45     set @C1=nchar(13)
 46     set @C2=nchar(10)
 47     
 48     
 49     declare cur_Object 
 50         cursor for 
 51             select object_name(a.object_id) As ObjectName,a.definition 
 52                 from sys.sql_modules a  
 53                     inner join sys.objects b on b.object_id=a.object_id
 54                         and b.is_ms_shipped=0
 55                         and not exists(select 1 
 56                                             from sys.extended_properties x
 57                                             where x.major_id=b.object_id
 58                                                 and x.minor_id=0
 59                                                 and x.class=1
 60                                                 and x.name='microsoft_database_tools_support'
 61                                         )
 62                 where b.type in('P','V','TR','FN','IF','TF')
 63                     and (b.name=@Object or @Object='All')
 64                     and b.name <>'sp_EncryptObject'
 65                     and a.definition is not null                    
 66                 order by Case 
 67                             when b.type ='V' then 1 
 68                             when b.type ='TR' then 2
 69                             when b.type in('FN','IF','TF') then 3 
 70                             else 4 end,b.create_date,b.object_id
 71                 
 72     open cur_Object
 73     fetch next from cur_Object into @Object,@sql
 74     while @@fetch_status=0
 75     begin
 76         
 77         Begin Try
 78                      
 79             if objectproperty(object_id(@Object),'ExecIsAfterTrigger')=0 set @Replace='As' ; else set @Replace='For ';
 80                 
 81             if (patindex('%'+@C1+@C2+@Replace+@C1+@C2+'%',@sql)>0)
 82             begin
 83                 set @sql=Replace(@sql,@C1+@C2+@Replace+@C1+@C2,@C1+@C2+'With Encryption'+@C1+@C2+@Replace+@C1+@C2)
 84             end
 85             else if(patindex('%'+@C1+@Replace+@C1+'%',@sql)>0)
 86             begin 
 87                 set @sql=Replace(@sql,@C1+@Replace+@C1,@C1+'With Encryption'+@C1+@Replace+@C1)
 88             end
 89             else if(patindex('%'+@C2+@Replace+@C2+'%',@sql)>0)
 90             begin 
 91                 set @sql=Replace(@sql,@C2+@Replace+@C2,@C2+'With Encryption'+@C2+@Replace+@C2)
 92             end
 93             else if(patindex('%'+@C2+@Replace+@C1+'%',@sql)>0)
 94             begin 
 95                 set @sql=Replace(@sql,@C2+@Replace+@C1,@C1+'With Encryption'+@C2+@Replace+@C1)
 96             end
 97             else if(patindex('%'+@C1+@C2+@Replace+'%',@sql)>0)
 98             begin 
 99                 set @sql=Replace(@sql,@C1+@C2+@Replace,@C1+@C2+'With Encryption'+@C1+@C2+@Replace)
100             end
101             else if(patindex('%'+@C1+@Replace+'%',@sql)>0)
102             begin 
103                 set @sql=Replace(@sql,@C1+@Replace,@C1+'With Encryption'+@C1+@Replace)
104             end
105             else if(patindex('%'+@C2+@Replace+'%',@sql)>0)
106             begin 
107                 set @sql=Replace(@sql,@C2+@Replace,@C2+'With Encryption'+@C2+@Replace)
108             end
109                     
110             set @type =
111                 case 
112                     when object_id(@Object,'P')>0 then 'Proc'
113                     when object_id(@Object,'V')>0 then 'View'
114                     when object_id(@Object,'TR')>0  then 'Trigger'
115                     when object_id(@Object,'FN')>0 or object_id(@Object,'IF')>0 or object_id(@Object,'TF')>0 then 'Function'
116                 end
117             set @sql=Replace(@sql,'Create '+@type,'Alter '+@type)
118             
119             Begin Transaction
120             exec(@sql)            
121             print N'已完成加密对象('+@type+')：'+@Object            
122             Commit Transaction
123             
124         End Try
125         Begin Catch
126             Declare @Error nvarchar(2047)
127             Set @Error='Object: '+@Object+@C1+@C2+'Error: '+Error_message()
128 
129 
130             Rollback Transaction          
131             print @Error
132             print @sql   
133         End Catch
134                     
135         fetch next from cur_Object into @Object,@sql
136         
137     end
138     
139     close cur_Object
140     deallocate cur_Object        
141 end
142  
143 Go
144 exec sp_ms_marksystemobject 'sp_EncryptObject' --标识为系统对象
145 go

如果SQL Server 2012，请修改下面两个位置的代码。在SQL Server 2012，建议在使用throw来代替raiserror。

解密方法：

解密过程，最重要采用异或方法：

[字符1]经过函数 fn_x（x）加密变成[加密后字符1]，如果我们已知[加密后字符1]，反过来查[字符1],可以这样：

[字符1] = [字符2] ^ fn_x([字符2]) ^ [加密后字符1]

这里我列举一个简单的例子：

 1 --创建加密函数（fn_x）
 2 if object_id('fn_x') is not null drop function fn_x
 3 go
 4 create function fn_x
 5 (
 6     @x nchar(1)
 7 )returns nchar(1)
 8 as
 9 begin
10 return(nchar((65535-unicode(@x))))
11 end
12 go
13 declare @nchar_1_encrypt nchar(1),@nchar_2 nchar(1)
14 
15 
16 --对字符'A'进行加密，存入变量@nchar_1_encrypt
17 set @nchar_1_encrypt=dbo.fn_x(N'A') 
18 
19 
20 --參考的字符@nchar_2
21 set @nchar_2='x' 
22 
23 --算出@nchar_1_encrypt 加密前的字符
24 select nchar(unicode(@nchar_2)^unicode(dbo.fn_x(@nchar_2))^unicode(@nchar_1_encrypt)) as [@nchar_1]
25 
26 /*
27 @nchar_1
28 --------------------
29 A
30 */

[注]： 从SQL Server 2000至 SQL Server 2012 采用异或方法都可以解密

用于解密的存储过程（sp_DecryptObject）：

  1 Use master
  2 Go
  3 if object_ID('[sp_DecryptObject]') is not null
  4     Drop Procedure [sp_DecryptObject]
  5 Go
  6 create procedure sp_DecryptObject 
  7 (
  8     @Object sysname,    --要解密的对象名：函数，存储过程，视图或触发器
  9     @MaxLength int=4000 --评估内容的长度
 10 )
 11 as
 12 set nocount on
 13 /* 1. 解密 */
 14  
 15 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'))
 16 begin
 17     --SQL Server 2008
 18     raiserror 50001 N'无效的对象！要解密的对象必须是函数，存储过程，视图或触发器。' 
 19 
 20     --SQL Server 2012
 21     --throw 50001, N'无效的对象！要解密的对象必须是函数，存储过程，视图或触发器。',1   
 22     return
 23 end
 24  
 25 if exists(select 1 from sys.sql_modules a where a.object_id=object_id(@Object) and a.definition is not null)
 26 begin
 27     --SQL Server 2008
 28     raiserror 50001 N'对象没有加密！' 
 29 
 30     --SQL Server 2012
 31     --throw 50001, N'无效的对象！要解密的对象必须是函数，存储过程，视图或触发器。',1 
 32     return
 33 end
 34  
 35 declare  @sql nvarchar(max)                --解密出来的SQL语句
 36         ,@imageval nvarchar(max)        --加密字符串
 37         ,@tmpStr nvarchar(max)            --临时SQL语句
 38         ,@tmpStr_imageval nvarchar(max) --临时SQL语句(加密后)
 39         ,@type char(2)                    --对象类型('P','V','TR','FN','IF','TF')
 40         ,@objectID int                    --对象ID
 41         ,@i int                            --While循环使用
 42         ,@Oject1 nvarchar(1000)
 43  
 44 set @objectID=object_id(@Object)
 45 set @type=(select a.type from sys.objects a where a.object_id=@objectID)
 46  
 47 declare @Space4000 nchar(4000)
 48 set @Space4000=replicate('-',4000)
 49  
 50 /*
 51 @tmpStr 会构造下面的SQL语句
 52 -------------------------------------------------------------------------------
 53 alter trigger Tr_Name on Table_Name with encryption for update as return /**/
 54 alter proc Proc_Name with encryption  as select 1 as col /**/
 55 alter view View_Name with encryption as select 1 as col /**/
 56 alter function Fn_Name() returns int with encryption as begin return(0) end/**/
 57 */
 58 set @Oject1=quotename(object_schema_name(@objectID))+'.'+quotename(@Object)
 59 set @tmpStr=
 60         case     
 61             when @type ='P ' then N'Alter Procedure '+@Oject1+' with encryption as select 1 as column1 '
 62             when @type ='V ' then N'Alter View '+@Oject1+' with encryption as select 1 as column1 '
 63             when @type ='FN' then N'Alter Function '+@Oject1+'() returns int with encryption as begin return(0) end '
 64             when @type ='IF' then N'Alter Function '+@Oject1+'() returns table with encryption as return(Select a.name from sys.types a) '
 65             when @type ='TF' then N'Alter Function '+@Oject1+'() returns @t table(name nvarchar(50)) with encryption as begin return end '
 66             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 ' 
 67         end        
 68  
 69     
 70 set @tmpStr=@tmpStr+'/*'+@Space4000
 71 set @i=0
 72 while @i < (ceiling(@MaxLength*1.0/4000)-1)
 73 begin
 74     set @tmpStr=@tmpStr+ @Space4000
 75     Set @i=@i+1
 76 end
 77 set @tmpStr=@tmpStr+'*/'
 78  
 79 ------------
 80 set @imageval =(select top(1) a.imageval from sys.sysobjvalues a where a.objid=@objectID and a.valclass=1)
 81  
 82 begin tran
 83 exec(@tmpStr)
 84 set @tmpStr_imageval =(select top(1) a.imageval from sys.sysobjvalues a where a.objid=@objectID and a.valclass=1)
 85  
 86 rollback tran
 87  
 88 -------------
 89 set @tmpStr=stuff(@tmpStr,1,5,'create')
 90 set @sql=''
 91 set @i=1
 92 while @i<= (datalength(@imageval)/2)
 93 begin
 94     set @sql=@sql+isnull(nchar(unicode(substring(@tmpStr,@i,1)) ^ unicode(substring(@tmpStr_imageval,@i,1))^unicode(substring(@imageval,@i,1)) ),'')
 95     Set @i+=1
 96 end
 97  
 98 /* 2. 列印 */
 99  
100  
101 declare @patindex int    
102 while @sql>''
103 begin
104     
105     set @patindex=patindex('%'+char(13)+char(10)+'%',@sql)
106     if @patindex >0
107     begin
108         print substring(@sql,1,@patindex-1)
109         set @sql=stuff(@sql,1,@patindex+1,'')
110     end    
111     else 
112     begin
113         set @patindex=patindex('%'+char(13)+'%',@sql)
114         if @patindex >0
115         begin
116             print substring(@sql,1,@patindex-1)
117             set @sql=stuff(@sql,1,@patindex,'')
118         end
119         else
120         begin
121             set @patindex=patindex('%'+char(10)+'%',@sql)
122             if @patindex >0
123             begin
124                 print substring(@sql,1,@patindex-1)
125                 set @sql=stuff(@sql,1,@patindex,'')
126             end        
127             else
128             begin
129                 print @sql
130                 set @sql=''
131             end    
132         end        
133     end
134         
135 end
136  
137 Go
138 exec sp_ms_marksystemobject 'sp_DecryptObject' --标识为系统对象
139 go

如果SQL Server 2012，请修改下面两个位置的代码。方法类似于前面的加密过程：

搭建测试环境：

在一个测试环境中（DB: Test），先执行上面的加密存储过程（sp_EncryptObject）和解密存储过程（sp_EncryptObject）;再创建两个表：TableA & TableB

use test
go
--创建表: 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

接下来，我们要创建6个未加密的对象（对象类型包含 'P','V','TR','FN','IF','TF'）：

1.视图（myView）：

1 if object_id('myView') is not null drop view myView
2 go
3 create view myView
4 As
5 select * from TableA;
6 go

2.触发器（MyTrigger）：

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.存储过程（MyProc）：

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.用户定义表值函数(TF)（MyFunction_TF）：

 1 if object_id('MyFunction_TF') is not null drop function MyFunction_TF
 2 go
 3 create function MyFunction_TF 
 4 (
 5 )
 6 returns  @t table
 7 (
 8     id int,
 9     data nvarchar(50)
10 )
11 As
12 begin
13 insert @t(id,data) select id,data from TableA
14 return
15 end
16 go

5.内联表值函数(IF) （MyFunction_IF）：

1 if object_id('MyFunction_IF') is not null drop function MyFunction_IF
2 go
3 create function MyFunction_IF 
4 (
5 )
6 returns table
7 As
8 return(select top(3) id, data from TableA order by id desc)
9 go

6.标量函数(FN)（MyFunction_FN）：

 1 if object_id('MyFunction_FN') is not null drop function MyFunction_FN
 2 go
 3 create function MyFunction_FN 
 4 (
 5 )
 6 returns nvarchar(50)
 7 As
 8 begin
 9 return(select top(1) data from TableA order by id desc)
10 end
11 go

当执行完了上面的1-6步骤的脚本，我们通过查询系统视图sys.sql_modules，可以看到未加密前的定义信息：

1 select b.name as object,b.type,a.definition
2     from sys.sql_modules a 
3         inner join sys.objects b on b.object_id=a.object_id
4         where b.create_date>=convert(date,getdate())
5         order by b.object_id

加密测试：

下面我就通过调用加密存储过程（sp_EncryptObject），一次性对它们进行加密：

use test
go
exec sp_EncryptObject 'all'
go

当我们再查回系统视图sys.sql_modules，会发现definition列返回的是null值，说明定义内容已经给加密：

解密测试：

解密过程，必须在DAC连接SQL Server，我们这里例子是从 SSMS(SQL Server Management Studio) 查询编辑器启动 DAC，如图：

解密存储过程（sp_DecryptObject），只能一次对一个存储过程、函数、视图或触发器，进行解密：

use test
go
exec sp_DecryptObject MyTrigger
go

当定义内容长度超过4000，我们可以指定@MaxLength的值，如：

exec sp_DecryptObject fn_My,20000
go

这里（fn_My）是一个函数，定义内容超过了8000：

... ...

小结：

虽然，上面的脚本，我已经在SQL Server 2008 R2 和SQL Server 2012测试过，但无法避免一些未知错误。