Transparent Data Encryption (often abbreviated to TDE) is a technology employed by

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

, IBM and

Oracle An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word '' ...

encrypt In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...

database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...

files. TDE offers encryption at file level. TDE solves the problem of protecting data at rest, encrypting databases both on the hard drive and consequently on

backup In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", w ...

media. It does not protect

data in transit Data in transit, also referred to as data in motion and data in flight, is data en route between source and destination, typically on a computer network. Data in transit can be separated into two categories: information that flows over the publi ...

nor

data in use Data in use is an information technology term referring to active data which is stored in a non-persistent digital state typically in computer random-access memory (RAM), CPU caches, or CPU registers. Scranton, PA data scientist Daniel Allen in 19 ...

. Enterprises typically employ TDE to solve compliance issues such as

PCI DSS The Payment Card Industry Data Security Standard (PCI DSS) is an information security standard used to handle credit cards from major card brands. The standard is administered by the Payment Card Industry Security Standards Council and its use i ...

which require the protection of data at rest. Microsoft offers TDE as part of its

Microsoft SQL Server Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which ma ...

2008, 2008 R2, 2012, 2014, 2016, 2017 and 2019. TDE was only supported on the Evaluation, Developer, Enterprise and Datacenter editions of Microsoft SQL Server, until it was also made available in the Standard edition for 2019. SQL TDE is supported by

hardware security module A hardware security module (HSM) is a physical computing device that safeguards and manages secrets (most importantly digital keys), performs encryption and decryption functions for digital signatures, strong authentication and other cryptograp ...

s from Thales e-Security, Townsend Security and SafeNet, Inc. IBM offers TDE as part of Db2 as of version 10.5 fixpack 5. It is also supported in cloud versions of the product by default, Db2 on Cloud and Db2 Warehouse on Cloud. Oracle requires the

Oracle Advanced Security Oracle Advanced Security, an extra-cost option for Oracle database environments, extends Oracle Net Services in the field of database computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery ...

option for Oracle 10g and 11g to enable TDE. Oracle TDE addresses encryption requirements associated with public and private privacy and security mandates such as PCI and

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

SB 1386. Oracle Advanced Security TDE column encryption was introduced in Oracle Database 10g Release 2. Oracle Advanced Security TDE tablespace encryption and support for

s (HSMs) were introduced with Oracle Database 11gR1. Keys for TDE can be stored in an HSM to manage keys across servers, protect keys with hardware, and introduce a separation of duties. The same key is used to encrypt columns in a table, regardless of the number of columns to be encrypted. These encryption keys are encrypted using the database server master key and are stored in a dictionary table in the database.

Microsoft SQL Server TDE

SQL Server utilizes an encryption hierarchy that enables databases to be shared within a cluster or migrated to other instances without re-encrypting them. The hierarchy consists of a combination of symmetric and asymmetric ciphers: * Windows Data Protection API (DPAPI) protects a single instance-wide Service Master Key (SMK). * The Service Master Key encrypts the Database Master Key (DMK). * The Database Master Key is used in conjunction with a certificate to encrypt the Database Encryption Key. * The Database Encryption Key is used to encrypt the underlying database files with either the AES or

3DES In cryptography, Triple DES (3DES or TDES), officially the Triple Data Encryption Algorithm (TDEA or Triple DEA), is a Symmetric-key algorithm, symmetric-key block cipher, which applies the Data Encryption Standard, DES cipher algorithm three ti ...

cipher. * The ''master'' database that contains various system level information, user accounts and management services is not encrypted. During database backups,

compression Compression may refer to: Physical science *Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression *Gas compression *Compression ratio, of a c ...

occurs after encryption. Due to the fact that strongly encrypted data cannot be significantly compressed, backups of TDE encrypted databases require additional resources. To enable automatic booting, SQL Server stores the lowest level encryption keys in persistent storage (using the

DPAPI Data Protection Application Programming Interface (DPAPI) is a simple cryptography, cryptographic application programming interface available as a built-in component in Windows 2000 and later versions of Microsoft Windows operating systems. In the ...

store). This presents a potential security issue because the stored keys can be directly recovered from a live system or from backups and used to decrypt the databases.Simon McAuliffe
"The Anatomy and (In)Security of Microsoft SQL Server Transparent Data Encryption (TDE)"
19-Mar-2016

References

{{Reflist

External links

Alternative 3rd party solution for all SQL Server Editions

Another alternative 3rd party solution for all SQL Server Editions

Enterprise Security Features Supported by Microsoft SQL Server 2008 R2 Editions

Security Features Supported by Microsoft SQL Server 2012 Editions

Understanding Transparent Data Encryption (TDE) (Microsoft)

Oracle Transparent Data Encryption best practices

* http://download.oracle.com/docs/cd/B19306_01/network.102/b14268/asotrans.htm#BABDFHHH
P6R's PKCS#11 Provider and Oracle TDE

Disk encryption

Microsoft SQL Server TDE

See also

References

External links