How to Enable Encryption at Rest in Oracle

How do I enable encryption at rest in Oracle Database?

Encryption at rest in Oracle secures data files, tablespaces, or specific columns with Transparent Data Encryption (TDE) so stolen disks expose only ciphertext.

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Description

Why use Oracle encryption at rest?

Protect customer PII, comply with PCI-DSS/GDPR, and remove the need for application-level encryption. Even if a drive is stolen, data stays unreadable without the wallet key.

What prerequisites must be in place?

Enterprise Edition with the Advanced Security option is required. The database must be in ARCHIVELOG mode, and you need OS access to store the keystore (wallet).

How do I create and open the keystore?

Run ADMINISTER KEY MANAGEMENT commands as SYSDBA to create, open, and back up the software keystore that stores the master key.

Step-by-step keystore setup

1) Create directory /u01/app/oracle/keystores.
2) CREATE KEYSTORE.
3) OPEN KEYSTORE.
4) SET ENCRYPTION KEY.

How do I encrypt an existing tablespace?

Use ALTER TABLESPACE … ENCRYPTION ONLINE. Oracle rewrites each block in the background, so the tablespace remains available.

Can I encrypt only sensitive columns?

Yes—ALTER TABLE … MODIFY (column ENCRYPT) encrypts just the chosen columns, minimizing CPU overhead.

How do I verify encryption status?

Query V$ENCRYPTED_TABLESPACES, DBA_TABLESPACES, and DBA_ENCRYPTED_COLUMNS for a quick audit trail.

Best practices for production

Rotate the master key regularly, automate wallet backups, enable FORCE KEYSTORE CLOSE on shutdown, and monitor for any auto-login wallet exposure.

How do I decrypt if requirements change?

Run ALTER TABLESPACE … DECRYPT or ALTER TABLE … MODIFY (column DECRYPT) during low-traffic windows to avoid I/O spikes.

What happens to performance?

Expect ≤5% CPU increase for AES256. Use hardware acceleration (AES-NI) and keep tablespaces small to minimize rekey time.

Why How to Enable Encryption at Rest in Oracle is important

How to Enable Encryption at Rest in Oracle Example Usage


-- Store Orders table in an encrypted tablespace
CREATE TABLE Orders (
  id           NUMBER PRIMARY KEY,
  customer_id  NUMBER REFERENCES Customers(id),
  order_date   DATE,
  total_amount NUMBER(12,2)
) TABLESPACE orders_tbs;

-- Verify encryption status
SELECT tablespace_name, encrypted
FROM   dba_tablespaces
WHERE  tablespace_name = 'ORDERS_TBS';

How to Enable Encryption at Rest in Oracle Syntax


-- 1. Create software keystore (wallet)
ADMINISTER KEY MANAGEMENT CREATE KEYSTORE '/u01/app/oracle/keystores' IDENTIFIED BY "MyKsPass123";

-- 2. Open keystore for use
ADMINISTER KEY MANAGEMENT SET KEYSTORE OPEN IDENTIFIED BY "MyKsPass123";

-- 3. Set master key (with automatic backup)
ADMINISTER KEY MANAGEMENT SET ENCRYPTION KEY IDENTIFIED BY "MyKsPass123" WITH BACKUP USING 'init_key_bkp';

-- 4. Encrypt existing tablespace that holds ecommerce data
ALTER TABLESPACE users ENCRYPTION ONLINE USING 'AES256' ENCRYPT;

-- 5. Create an encrypted tablespace for financial data
CREATE TABLESPACE orders_tbs DATAFILE '/u01/oradata/ORDERS01.dbf' SIZE 1G ENCRYPTION USING 'AES256' DEFAULT STORAGE(ENCRYPT);

-- 6. Column-level encryption example
ALTER TABLE Customers MODIFY (email ENCRYPT USING 'AES256');

Common Mistakes

Ignoring keystore backups: Failing to back up the keystore means a lost master key can render the entire database unreadable. Always run SET ENCRYPTION KEY … WITH BACKUP and copy the backup off-box.
Leaving auto-login wallet enabled in prod: Auto-login wallets ease restarts but expose keys to anyone with file-system access. Disable auto-login on production and use password-protected wallets instead.

Frequently Asked Questions (FAQs)

Does TDE require application changes?

No. Oracle encrypts/decrypts at the storage layer, so applications continue to issue normal SQL.

Can I encrypt only new data?

Column/Tablespace encryption rewrites existing blocks; you cannot encrypt just future rows. Use different tablespaces and move fresh data if partial coverage is needed.