T-SQL实现MD5加密函数

/***************************************************************************** 
* Name: T-SQL MD5算法实现 
* Author: Rambo Qian 
* Create Date: 2003-04-10 
* Last Modified by: Rambo Qian 
* Last Update Date: 2003-04-16 
* Version: V1.0.00 
*****************************************************************************/ 
GO 
 
IF EXISTS(SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[MD5_m_OnBits]') AND xtype IN(N'FN', N'IF', N'TF')) 
  DROP FUNCTION [dbo].[MD5_m_OnBits] 
GO 
/***************************************************************************** 
* Name: MD5_m_OnBits 
* Description: 常数组 
*****************************************************************************/ 
CREATE FUNCTION dbo.MD5_m_OnBits( 
  @i  TINYINT 
) 
RETURNS INT 
WITH ENCRYPTION 
AS 
BEGIN 
  DECLARE @iRes  INT 
  SELECT @iRes = 
    CASE @i 
      WHEN 0 THEN 1      -- 00000000000000000000000000000001 
      WHEN 1 THEN 3      -- 00000000000000000000000000000011 
      WHEN 2 THEN 7      -- 00000000000000000000000000000111 

      WHEN 3 THEN 15      -- 00000000000000000000000000001111 
      WHEN 4 THEN 31      -- 00000000000000000000000000011111 
      WHEN 5 THEN 63      -- 00000000000000000000000000111111 
      WHEN 6 THEN 127     -- 00000000000000000000000001111111 
      WHEN 7 THEN 255     -- 00000000000000000000000011111111 
      WHEN 8 THEN 511     -- 00000000000000000000000111111111 
      WHEN 9 THEN 1023     -- 00000000000000000000001111111111 
      WHEN 10 THEN 2047     -- 00000000000000000000011111111111 
      WHEN 11 THEN 4095     -- 00000000000000000000111111111111 
      WHEN 12 THEN 8191     -- 00000000000000000001111111111111 
      WHEN 13 THEN 16383    -- 00000000000000000011111111111111 
      WHEN 14 THEN 32767    -- 00000000000000000111111111111111 
      WHEN 15 THEN 65535    -- 00000000000000001111111111111111 
      WHEN 16 THEN 131071    -- 00000000000000011111111111111111 
      WHEN 17 THEN 262143    -- 00000000000000111111111111111111 
      WHEN 18 THEN 524287    -- 00000000000001111111111111111111 
      WHEN 19 THEN 1048575   -- 00000000000011111111111111111111 
      WHEN 20 THEN 2097151   -- 00000000000111111111111111111111 
      WHEN 21 THEN 4194303   -- 00000000001111111111111111111111 
      WHEN 22 THEN 8388607   -- 00000000011111111111111111111111 
      WHEN 23 THEN 16777215   -- 00000000111111111111111111111111 
      WHEN 24 THEN 33554431   -- 00000001111111111111111111111111 
      WHEN 25 THEN 67108863   -- 00000011111111111111111111111111 
      WHEN 26 THEN 134217727  -- 00000111111111111111111111111111 
      WHEN 27 THEN 268435455  -- 00001111111111111111111111111111 
      WHEN 28 THEN 536870911  -- 00011111111111111111111111111111 
      WHEN 29 THEN 1073741823  -- 00111111111111111111111111111111 
      WHEN 30 THEN 2147483647  -- 01111111111111111111111111111111 
      ELSE 0 
    END