Red Hat Directory Server 8.0 Administrator's Guide

For highly sensitive information, this potential for information loss could present a significant

security risk. In order to remove that security risk, Directory Server allows portions of its

database to be encrypted. Once encrypted, the data are safe even in the event that an attacker

has a copy of the server's database files.

Database encryption allows attributes to be encrypted in the database. Both encryption and the

encryption cipher are configurable per attribute per backend. When configured, every instance

of a particular attribute, even index data, is encrypted for every entry stored in that database.

NOTE

To enable database encryption on an attribute with existing stored data, export

the database to LDIF first, then make the configuration change, then re-import

the data to the database. The server does not enforce consistency between

encryption configuration and stored data; therefore, pay careful attention that all

existing data are exported before enabling or disabling encryption.

Indexed attributes may be encrypted, and database encryption is fully compatible with indexing.

The contents of the index files that are normally derived from attribute values are also encrypted

to prevent an attacker from recovering part or all of the encrypted data from an analysis of the

indexes.

Since the server pre-encrypts all index keys before looking up an index for an encrypted

attribute, there is some effect on server performance for searches that make use of an

encrypted index, but the effect is not serious enough that it is no longer worthwhile to use an

index.

2.3.1. Encryption Keys

In order to use database encryption, the server must be configured for SSL and have SSL

enabled because database encryption uses the server's SSL encryption key and the same PIN

input methods as SSL. The PIN must either be entered manually upon server startup or a PIN

file must be used.

Randomly generated symmetric cipher keys are used to encrypt and decrypt attribute data. A

separate key is used for each configured cipher. These keys are wrapped using the public key

from the server's SSL certificate, and the resulting wrapped key is stored within the server's

configuration files. The effective strength of the database encryption is never higher than the

strength of the server's SSL key used for wrapping. Without access to the server's private key, it

is not possible to recover the symmetric keys from the wrapped copies.

CAUTION

Database Encryption