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：

Use master
Go
if object_ID('[sp_EncryptObject]') is not null
    Drop Procedure [sp_EncryptObject]
Go
create procedure sp_EncryptObject 
(
    @Object sysname='All'
)
as
/*
    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
    调用方法：
    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'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。'

            --SQL Server 2012
            --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  

            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'对象已经加密！'

            --SQL Server 2012
            --throw 50001, N'对象已经加密！',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'已完成加密对象('+@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' --标识为系统对象
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：

--创建加密函数（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)


--对字符'A'进行加密，存入变量@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]：  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）：

Use master
Go
if object_ID('[sp_DecryptObject]') is not null
    Drop Procedure [sp_DecryptObject]
Go
create procedure sp_DecryptObject 
(
    @Object sysname,    --要解密的对象名：函数，存储过程，视图或触发器
    @MaxLength int=4000 --评估内容的长度
)
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'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。' 

    --SQL Server 2012
    --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   
    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'对象没有加密！' 

    --SQL Server 2012
    --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 
    return
end
 
declare  @sql nvarchar(max)                --解密出来的SQL语句
        ,@imageval nvarchar(max)        --加密字符串
        ,@tmpStr nvarchar(max)            --临时SQL语句
        ,@tmpStr_imageval nvarchar(max) --临时SQL语句(加密后)
        ,@type char(2)                    --对象类型('P','V','TR','FN','IF','TF')
        ,@objectID int                    --对象ID
        ,@i int                            --While循环使用
        ,@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 会构造下面的SQL语句
-------------------------------------------------------------------------------
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' --标识为系统对象
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）：

if object_id('myView') is not null drop view myView
go
create view myView
As
select * from TableA;
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）：

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.内联表值函数(IF) （MyFunction_IF）：

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.标量函数(FN)（MyFunction_FN）：

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

 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：

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 。