How to encrypt/decrypt string in sql server

--ENCRIPT
CREATE FUNCTION FNC_ENCRIPTION_PW(@str nvarchar(4000))
RETURNS varbinary(8000)
AS
BEGIN
DECLARE @encript varbinary(8000)
SET @encript = ENCRYPTBYPASSPHRASE('KEY',@str)
RETURN (@encript)
END
GO


--DECRIPT
CREATE FUNCTION FNC_DECRIPTION_PW(@encryp varbinary(8000))
RETURNS nvarchar(4000)
AS
BEGIN
DECLARE @decript varbinary(4000)
SET @decript = DECRYPTBYPASSPHRASE('KEY',@encryp)
RETURN (@decript)
END
GO



--HOW USE
DECLARE @decript nvarchar(4000)
DECLARE @encript varbinary(8000)
SET @encript = [dbo].[FNC_ENCRIPTION_PW]('password')
SELECT @encript
SET @decript = [dbo].[FNC_DECRIPTION_PW](@encript)
SELECT @decript

If Help...
For decrypt
-----------------------

DECLARE @pwd varchar(100),@OriginalPwd as varchar(100),@OriginalString as Varchar(100),@Count as int,@iLoop as int,@temp as int,@rightChar as int    

Set @pwd =@Password    
set @Count =LEN (@pwd)    
set @iLoop = 1    
Set @rightChar = 1    
set @OriginalString = ''    
set @OriginalPwd=''    
set @temp = 1    
    
 -- SET NOCOUNT ON added to prevent extra result sets from    
 -- interfering with SELECT statements.    
 --SET NOCOUNT ON;    
 SELECT @OriginalString= REVERSE(@pwd)    
     
 WHILE @temp<=@Count    <pre lang="SQL">
 begin    
  SELECT @OriginalPwd = @OriginalPwd + Char(ascii(RIGHT(LEFT(@OriginalString,@rightChar),1))-@iLoop)         
   if @iLoop=4    
    begin    
     set @iLoop=0    
    end    
  set @iLoop=@iLoop+1       
  set @rightChar=@rightChar+1       
  set @temp=@temp+1    
 END    
 select password=@OriginalPwd  
 PRINT 'Original String Is :- ' +@OriginalPwd    

And i M Sure Y Are able To Manage It For Encrypt....