SQL存储过程解密

CREATE TABLE [dbo].[SQL_DECODE](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [SQLTEXT] [nvarchar](max) NOT NULL,
 CONSTRAINT [ID] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)
) ON [PRIMARY]

GO

CREATE PROCEDURE [dbo].[DECODE_PROC](
    @PROC_NAME SYSNAME = NULL
)
AS
SET NOCOUNT ON

DECLARE @PROC_NAME_LEN INT    --存储过程名长度
DECLARE @MAX_COL_ID SMALLINT    --最大列ID
SELECT @MAX_COL_ID = MAX(subobjid) FROM sys.sysobjvalues WHERE objid = OBJECT_ID(@PROC_NAME) GROUP BY imageval

SELECT @PROC_NAME_LEN = DATALENGTH(@PROC_NAME) + 29
DECLARE @REAL_01 NVARCHAR(MAX)    --真实加密存储过程数据
DECLARE @FACK_01 NVARCHAR(MAX)    --修改为假的存储过程，长度（40003 - 存在过程名长度），原理不明？
DECLARE @FACK_ENCRYPT_01 NVARCHAR(MAX)    --伪加密存储过街程数据
DECLARE @REAL_DECRYPT_01 NVARCHAR(MAX)    --最终解密后的数据，初始化为原始加密长度的一半的“A”，原理不明？

SET @REAL_01 = (
    SELECT imageval FROM sys.sysobjvalues WHERE objid = object_id(@PROC_NAME) AND valclass = 1 AND subobjid = 1
)

DECLARE @REAL_DATA_LEN BIGINT
SET @REAL_DATA_LEN = DATALENGTH(@REAL_01)
--PRINT @REAL_DATA_LEN

DECLARE @FACK_LEN BIGINT
SET @FACK_LEN = @REAL_DATA_LEN * 10    --改造：假的长度在原真实数据长度上放大10倍

--此处需将NVARCHAR显示转换成NVARCHAR(MAX)，不然将只能产生4K长度
SET @FACK_01 = ‘ALTER PROCEDURE ‘ + @PROC_NAME + ‘ WITH ENCRYPTION AS ‘ + REPLICATE(CONVERT(NVARCHAR(MAX), ‘-‘), @FACK_LEN - @PROC_NAME_LEN)
--PRINT ‘@FACK_01 = ‘ + STR(LEN(@FACK_01))
EXECUTE (@FACK_01)
SET @FACK_ENCRYPT_01 = (
    SELECT imageval FROM sys.sysobjvalues WHERE objid = object_id(@PROC_NAME) AND valclass = 1 AND subobjid = 1
)

SET @FACK_01 = ‘CREATE PROCEDURE ‘ + @PROC_NAME + ‘ WITH ENCRYPTION AS ‘ + REPLICATE(CONVERT(VARCHAR(MAX), ‘-‘), @FACK_LEN - @PROC_NAME_LEN)
SET @REAL_DECRYPT_01 = REPLICATE(CONVERT(NVARCHAR(MAX), N‘A‘), (DATALENGTH(@REAL_01) /2))
--PRINT ‘LEN(@REAL_DECRYPT_01) = ‘ + STR(LEN(@REAL_DECRYPT_01))


--按位对 @REAL_01、 @FACK_01、 @REAL_DECRYPT_01 进行异或操作。
DECLARE @INT_PROC_SPACE BIGINT
SET @INT_PROC_SPACE = 1
WHILE @INT_PROC_SPACE <= (DATALENGTH(@REAL_01) /2 )
BEGIN
    SET @REAL_DECRYPT_01 = STUFF(
        @REAL_DECRYPT_01, 
        @INT_PROC_SPACE, 
        1, 
        NCHAR(UNICODE(SUBSTRING(@REAL_01, @INT_PROC_SPACE, 1)) ^ (UNICODE(SUBSTRING(@FACK_01, @INT_PROC_SPACE, 1)) ^ UNICODE(SUBSTRING(@FACK_ENCRYPT_01, @INT_PROC_SPACE, 1))))
    )
    SET @INT_PROC_SPACE = @INT_PROC_SPACE + 1
END

--移除WITH ENCRYPTION
SET @REAL_DECRYPT_01 = REPLACE(@REAL_DECRYPT_01, ‘WITH ENCRYPTION‘, ‘‘)
INSERT INTO [SQL_DECODE] VALUES (@REAL_DECRYPT_01)

--PRINT ‘@REAL_DECRYPT_01 = ‘ + @REAL_DECRYPT_01
--PRINT ‘LEN(@REAL_DECRYPT_01) = ‘ + STR(LEN(@REAL_DECRYPT_01))

--删除原存储过程
SET @FACK_01 = ‘DROP PROCEDURE ‘ + @PROC_NAME
EXEC(@FACK_01)

GO

exec dbo.DECODE_PROC ‘存储过程名‘