IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Hardware & Software Remarks
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S 4.72 Database encryption
Initiation responsibility: Head of IT Section, IT Security Management
Implementation responsibility: Administrators, application developers
Depending on the type of information stored in a database and the related
requirements of confidentiality and integrity, it might be necessary to encrypt
this data. A distinction can be made between online and offline encryption
here:
- During online encryption, the data are encrypted and decrypted while the
IT systems are in operation, without the involved users being aware of this
process. For this purpose, tools can be used which either encrypt the entire
hard disk at the operating-system level, or only encrypt the application data
of the database.
- During offline encryption, the data are only encrypted after having been
processed, and decrypted before undergoing further processing. In general,
this is done with tools which are not part of the database system. This
technique can prove particularly useful for data backups and data
transmissions. In this case, it must be ensured that sufficient disk space is
available, as encrypting and decrypting can only be carried out successfully
if the hard disk is capable of holding both the original and the encrypted
version of the database.
Furthermore, it is possible to save data as plain text in the database, but
transmit it in encrypted form during access via a network. This can be
realised, for example, with the Secure Network Services of the Oracle
SQL*Net product group.
Which data should be encrypted using which techniques is best decided on
during selection of the standard database software (refer to S 2.124 Selection
of suitable database software). During this process, the requirements of data
encryption should be compared with the corresponding features of the
database software. However, it should at least be ensured that the passwords
of the database user IDs are stored in encrypted form.
If the encryption requirements cannot be fulfilled completely by any of the
standard database software available on the market, the use of add-ons should
be considered for the purpose of closing the security gaps. If no add-ons are
available either, a concept for implementing an encryption strategy at the
corporation or authority should be prepared.
Additional controls:
- Are appropriate encryption techniques offered by the database or add-ons?
- Have the responsible persons been briefed on proper key management?
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IT-Baseline Protection Manual: Oktober 2000