SQL Server中加密是層級(jí)的，每一個(gè)上層為下提供保護(hù)。如圖：
實(shí)例：
/**
SMK(Service Master Key)在SQL Server安裝時(shí)生成,由Windows DPAPI(Data Protection API)提供保護(hù)
**/
/**創(chuàng)建數(shù)據(jù)庫(kù)級(jí)別DMK(Database Master Key),受SMK保護(hù)**/
create master key encryption by password=N'Passw0rd'
go
/**數(shù)據(jù)庫(kù)內(nèi)的加密對(duì)象受DMK保護(hù)
支持的對(duì)稱加密算法:DES | TRIPLE_DES | TRIPLE_DES_3KEY | RC2 | RC4 | RC4_128| DESX | AES_128 | AES_192 | AES_256
非對(duì)稱加密算法：RSA_512 | RSA_1024 | RSA_2048
注意避免使用RC,DESX類算法,2014之后會(huì)刪除此功能
**/
--1.創(chuàng)建非對(duì)稱密鑰.
create asymmetric key asyc_key_enc
with algorithm=RSA_1024
encryption by password=N'Pass@word'
go
--2.創(chuàng)建對(duì)稱密鑰.
create symmetric key symc_key_enc
with algorithm=Triple_DES
encryption by password=N'Pass@word'
go
--3.創(chuàng)建證書.證書也可被其它方式保護(hù)
create certificate cert_ENC
with subject='certificate for ENC',expiry_date='20990101'
go
--4.對(duì)稱密鑰可由以上三種方式提供加密保護(hù)
--4.1 由非對(duì)稱密鑰加密
create symmetric key symc_key_enc_byAsyc
with algorithm=AES_128
encryption by asymmetric key asyc_key_enc
go
--4.2 由對(duì)稱密鑰加密
open symmetric key symc_key_enc
decryption by password=N'
Pass@word';
create symmetric key symc_key_enc_bySymc
with algorithm = DES
encryption by symmetric key symc_key_enc
go
--4.3 由證書加密
create symmetric key symc_key_enc_byCert
with algorithm =AES_128
encryption by certificate cert_ENC
go
/**列級(jí)數(shù)據(jù)加密和解密.MSSQL提供以下4對(duì)加密/解密函數(shù)對(duì)列數(shù)據(jù)加密
EncryptByCert() 和DecryptByCert()—利用證書對(duì)數(shù)據(jù)進(jìn)行加密和解密
EncryptByAsymKey() and DecryptByAsymKey()—利用非對(duì)稱密鑰對(duì)數(shù)據(jù)進(jìn)行加密和解密
EncryptByKey() and DecryptByKey()—利用對(duì)稱密鑰對(duì)數(shù)據(jù)進(jìn)行加密和解密
EncryptByPassphrase() and DecryptByPassphrase()—利用密碼字段產(chǎn)生對(duì)稱密鑰對(duì)數(shù)據(jù)進(jìn)行加密和解密
注意:被加密和解密的數(shù)據(jù),必需是varbinary類型
**/
--以ENCRYPTBYKEY為例，其它的大同小異
--對(duì)***號(hào)IDN進(jìn)行加密和解密
create table tb(IDN int,Name varchar(20));
insert into tb
values (123456789,'BigBrother'),(090807001,'SpiderMan'),(336655789,'SuperMan')
go
--新增列Ency_IDN存儲(chǔ)加密數(shù)據(jù),使用之前由非對(duì)稱密鑰加密的對(duì)稱密鑰symc_key_enc_byAsyc來(lái)加密數(shù)據(jù)
alter table tb add Ency_IDN varbinary(128);
go
open symmetric key symc_key_enc_byAsyc
decryption by asymmetric key asyc_key_enc
with password=N'
Pass@word';
update tb
set Ency_IDN=ENCRYPTBYKEY(KEY_GUID('symc_key_enc_byAsyc'),CONVERT(Varbinary,IDN));--加密前要轉(zhuǎn)成varbinary
close symmetric key symc_key_enc_byAsyc --顯式關(guān)閉對(duì)稱密鑰
go
--解密被加密的列數(shù)據(jù)
open symmetric key symc_key_enc_byAsyc
decryption by asymmetric key asyc_key_enc
with password=N'
Pass@word';
select IDN,Ency_IDN,convert(int,DECRYPTBYKEY(Ency_IDN))as Decr_IDN
from tb;
close symmetric key symc_key_enc_byAsyc --顯式關(guān)閉對(duì)稱密鑰
go
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