用DecryptByKey函数解密字段问题?
我把密码字段设置为varchar,然后创建密钥,打开密钥,插入数据,可是读取的时候却显示为NULL,请问怎么回事
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '??xxx'CREATE SYMMETRIC KEY dcmy WITH ALGORITHM = DES ENCRYPTION BY PASSWORD = 'xxx??'--打开对称密钥OPEN SYMMETRIC KEY dcmy DECRYPTION BY PASSWORD = 'xxx??'--以加密的方式存放数据INSERT INTO [tb_Teacher] (TeaName,TeaPwd) VALUES ('老师五',EncryptByKey(Key_GUID('dcmy'), '456456'))select * from tb_Teacherselect CONVERT(varchar, DecryptByKey(TeaPwd)) from tb_Teachercreate table [tb_Teacher](TeaName nvarchar(20),TeaPwd nvarchar(200));GOCREATE SYMMETRIC KEY dcmy WITH ALGORITHM = DES ENCRYPTION BY PASSWORD = '1234567890'--打开对称密钥OPEN SYMMETRIC KEY dcmy DECRYPTION BY PASSWORD = '1234567890'--以加密的方式存放数据INSERT INTO [tb_Teacher] (TeaName,TeaPwd) VALUES ('老师五',EncryptByKey(Key_GUID('dcmy'), '456456'))select * from tb_Teacher/*TeaName TeaPwd-------------------- -----------------老师五 ?菮??劦洼?? ????娺簍????*/select CONVERT(varchar, DecryptByKey(TeaPwd)) from tb_Teacher/*456456*/