（4.16）存储过程的加密与解密

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