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