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Oracle Transparent Data Encryption - 透明数据加密

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    Oracle的透明数据加密,是Oracle高级安全选项中的一个部分,需要额外支付软件费用。

    这一选项,可以结合多种手段进行加密,包括使用Wallet(PKCS#12标准)以及支持PKCS#11 RAS硬件设备。

    在10g中,透明加密支持基于列级的加密,而在Oracle 11gR2中,增加了基于表空间的透明加密。

    以下是官方文档中关于加密解密的流程图:

    

    以下是一个简单测试。

    首先在SQLNET.ora文件中增加如下一段:

    

ENCRYPTION_WALLET_LOCATION=

     (SOURCE=(METHOD=FILE)(METHOD_DATA=

     (DIRECTORY=D:\\Oracle\\11.2.0\\NETWORK\\ADMIN\\encryption_wallet\\)))

    

    在SQL*Plus中创建Wallet密钥:

    

SQL> connect / as sysdba

    Connected.

    SQL> alter system set encryption key authenticated by "eygle";

    System altered.

    

    关闭和打开Wallet:

    

SQL> alter system set encryption wallet close;

    alter system set encryption wallet close

    *

    ERROR at line 1:

    ORA-28390: auto login wallet not open

    SQL> alter system set encryption wallet close identified by "eygle";

    System altered.

    SQL> alter system set wallet open identified by "eygle";

    System altered.

    

    在创建数据表时可以指定加密:

    

SQL> connect eygle/eygle

    Connected.

    SQL> create table tde (id number(10),data varchar2(50) encrypt);

    Table created.

    SQL> insert into tde select user_id,username from dba_users;

    9 rows created.

    SQL> commit;

    Commit complete.

    SQL> connect / as sysdba

    Connected.

    SQL> select * from eygle.tde;

     ID DATA

    ---------- --------------------------------------------------

     0 SYS

     5 SYSTEM

     34 EYGLE

     9 OUTLN

     31 APPQOSSYS

     30 DBSNMP

     32 WMSYS

     14 DIP

     21 ORACLE_OCM

    

    加密和解密是自动进行的。

    查询dba_encrypted_columns视图可以找到加密列:

    

SQL> select * from dba_encrypted_columns;

    OWNER      TABLE_NAME      COLUMN_NAME          ENCRYPTION_ALG                SAL INTEGRITY_AL

    ---------- --------------- -------------------- ----------------------------- --- ------------

    EYGLE      TDE             DATA                 AES 192 bits key              YES SHA-1

    

    如果关闭Wallet,则加密列不可访问:

    

SQL> select * from eygle.tde;

    select * from eygle.tde

          *

    ERROR at line 1:

    ORA-28365: wallet is not open

    SQL> alter system set encryption wallet close identified by "eygle";

    System altered.

    SQL> select * from eygle.tde;

    select * from eygle.tde

          *

    ERROR at line 1:

    ORA-28365: wallet is not open

    SQL> desc eygle.tde

    Name                                                              Null?    Type

    ----------------------------------------------------------------- -------- -------------------------------

    ID                                                                         NUMBER(10)

    DATA                                                                       VARCHAR2(50) ENCRYPT

    SQL> select id from eygle.tde;

     ID

    ----------

     0

     5

     34

     9

     31

     30

     32

     14

     21

    9 rows selected.

    

    在加密列时,存在两个选项:Salt和No Salt。

    Salt在加密前对数据增加随即字符串,增加破解的难度,使得同样的字符串加密结果不同;而对于NO Salt,则同样字符串可以获得同样的加密输出,其安全性相对略低。

    在加密列上,如果使用Salt方式,则不能创建索引,Salt加密和索引两种属性互斥,不能同时设置:

    SQL> create index idx01 on tde(data);

    create index idx01 on tde(data)

                *

    ERROR at line 1:

    ORA-28338: Column(s) cannot be both indexed and encrypted with salt

    当使用缺省Salt方式加密时,此时允许对于加密列创建索引:

    SQL> create table tde2 (id number(10) encrypt no salt,data varchar2(50) );

    Table created.

    SQL> insert into tde2 select user_id,username from dba_users;

    9 rows created.

    SQL> select * from tde2;

     ID DATA

    ---------- --------------------------------------------------

     0 SYS

     5 SYSTEM

     34 EYGLE

     9 OUTLN

     31 APPQOSSYS

     30 DBSNMP

     32 WMSYS

     14 DIP

     21 ORACLE_OCM

    9 rows selected.

    SQL> commit;

    Commit complete.

    SQL> create index idx1 on tde2(id);

    Index created.

    当执行导出时,Oracle会给出提示:

    

D:\\>expdp eygle/eygle directory=temp dumpfile=tde2.dmp tables=TDE

    Export: Release 11.2.0.2.0 - Production on Thu Sep 8 15:35:19 2011

    Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

    Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production

    With the Partitioning, OLAP, Data Mining and Real Application Testing options

    Starting "EYGLE"."SYS_EXPORT_TABLE_01":  eygle/******** directory=temp dumpfile=tde2.dmp tables=TDE

    Estimate in progress using BLOCKS method...

    Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

    Total estimation using BLOCKS method: 64 KB

    Processing object type TABLE_EXPORT/TABLE/TABLE

    . . exported "EYGLE"."TDE"                               5.562 KB       9 rows

    ORA-39173: Encrypted data has been stored unencrypted in dump file set.

    Master table "EYGLE"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded

    ******************************************************************************

    Dump file set for EYGLE.SYS_EXPORT_TABLE_01 is:

     D:\\TEMP\\TDE2.DMP

    Job "EYGLE"."SYS_EXPORT_TABLE_01" completed with 1 error(s) at 15:35:23

    

    提示表明,加密数据在转储文件中,以非加密方式存储,但是当执行导入时,需要存在加密Wallet才能够执行导入,否则将会出现ORA-28362的异常。

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