Encrypt tables with Transparent Data Encryption (TDE)
Configure Transparent Data Encryption (TDE) to protect all data in a table, except for the primary key columns. Different tables can use different keys.
Two keys are used for table encryption:
-
Local encryption key: Encrypts/decrypts internal table encryption key values.
-
Table encryption key: HCD creates a single key entry in the
hcd_system.encrypted_keys
table for each cipher algorithm, key strength, and local encryption key combination that is defined for table encryption.Tables with the same encryption settings use the same encryption key.
Data is encrypted when written to SSTables on disk. Applications can read and write to SSTables that use different encryption algorithms or no encryption at all.
Create a table with encryption and compression
DataStax recommends creating tables with both encryption and compression enabled, using EncryptingLZ4Compressor
as the encryption class.
Prerequisites
-
cipher_algorithm[/mode/padding]
DSE supports the following
JCE
cipher algorithms:-
AES/CBC/PKCS5Padding (valid with length 128, 192, or 256).
-
AES/ECB/PKCS5Padding (valid with length 128, 192, or 256)
-
DES/CBC/PKCS5Padding (valid with length 56)
-
DESede/CBC/PKCS5Padding (valid with length 112 or 168)
-
Blowfish/CBC/PKCS5Padding (valid with length 32-448)
-
RC2/CBC/PKCS5Padding (valid with length 40-128) Default value:
AES/CBC/PKCS5Padding
(with length 128).
-
Complete the key setup described in Setting up local encryption keys.
Use the cqlsh
utility to create a table with encryption and compression
-
Change to the keyspace where you want to create the table. The following examples use
test
as the keyspace name:cqlsh
USE test;
-
Create the table with encryption and compression.
The following example encrypts a table named
encryption_test
using theDESede
algorithm, with a key length of112
. Data is compressed using theEncryptingLZ4Compressor
compressor.If the HCD account does not have read/write permission or the file is missing, an error message Failed to initialize Encryptor displays.
CREATE TABLE test.encryption_test (d int PRIMARY KEY) WITH COMPRESSION = { 'class': 'EncryptingLZ4Compressor', 'cipher_algorithm' : 'DESede/CBC/PKCS5Padding', 'secret_key_strength' : 112, 'system_key_file' : 'system_key' };
See Table encryption options and syntax for more information.
-
To change the encryption settings, use the
ALTER TABLE
command and specify the settings to modify.The following command changes the encryption key used to encrypt the table data, and modifies the key strength.
ALTER TABLE test.encryption_test WITH COMPRESSION = { 'class': 'EncryptingLZ4Compressor', 'cipher_algorithm' : 'AES/ECB/PKCS5Padding', 'secret_key_strength' : 128, 'system_key_file' : 'system_key' };
-
If you changed encryption settings, run the following command on all nodes in the cluster to rewrite the SSTables using the new encryption key:
nodetool upgradesstables -a test encryption_test
Table encryption options and syntax
When a table definition uses an encryption class, all table data except for primary keys is encrypted with a key entry from the hcd_system.encrypted_keys
table.
If no keys match the cipher_algorithm
, secret_key_strength
, and system_key_file
settings, a new key is created and added to the table.
The following syntax only shows encryption options.
All other compression options, such as |
Syntax
COMPRESSION = {
'class' : '<encryption_class>'[,
'cipher_algorithm' : '<cipher_algorithm_type>'] [,
'secret_key_strength' : <length>] [,
'system_key_file': '<key_filename>'] };
Options
-
encryption_class
Specifies the encryption type. Use one of the class names from the following table. (Required)
Name Encrypts Compresses Encryptor [1]
Yes
No
EncryptingLZ4Compressor
Yes
Yes
EncryptingDeflateCompressor
Yes
Yes
EncryptingSnappyCompressor
Yes
Yes
[1] When using the Encryptor class, specify a larger young generation heap (the
-Xmn
parameter) to improve garbage collection (GC).cipher_algorithm_type
-
Sets the type of encryption key. DSE supports the following JCE algorithms and corresponding
length
.
-
cipher_algorithm[/mode/padding]
DSE supports the following
JCE
cipher algorithms:-
AES/CBC/PKCS5Padding (valid with length 128, 192, or 256).
-
AES/ECB/PKCS5Padding (valid with length 128, 192, or 256)
-
DES/CBC/PKCS5Padding (valid with length 56)
-
DESede/CBC/PKCS5Padding (valid with length 112 or 168)
-
Blowfish/CBC/PKCS5Padding (valid with length 32-448)
-
RC2/CBC/PKCS5Padding (valid with length 40-128) Default value:
AES/CBC/PKCS5Padding
(with length 128).length
-
Specifies the length of the encryption key.
Default:
128
. (Optional) key_filename
-
Specifies the file name of the local encryption key used to encrypt the table key.
Default:
system_key
. (Optional)
-