How to encrypt Data at Rest in ClickHouse?

Advanced Data Security Series: How to encrypt Data at Rest in ClickHouse?


Why should Data at Rest be encrypted?

Encrypting data at rest is important because it helps to protect sensitive information in case of a data breach or unauthorized access. When data is at rest, it means that it is stored on a physical medium, such as a hard drive, a USB drive, or a backup tape. If an attacker gains physical access to the medium, they could potentially extract sensitive information from the data. Encryption at rest helps to protect against this type of attack by making it difficult for an attacker to extract any useful information from the data.

Here are a few reasons why data at rest should be encrypted:

  1. Compliance: Many industries are subject to regulations that require sensitive data to be encrypted at rest. Encrypting data at rest helps organizations to meet compliance requirements and avoid penalties.
  2. Data protection: Encryption at rest helps to protect sensitive information, such as personal information, financial information, and intellectual property, from unauthorized access, theft, or loss.
  3. Data integrity: Encryption at rest helps to protect the integrity of data by ensuring that it cannot be tampered with or modified without permission.
  4. Protecting against physical attacks: Encryption at rest is an effective way to protect against physical attacks, such as theft or a lost device, as it makes it difficult for an attacker to extract any useful information from the data.
  5. Protecting against cyber-attacks: Encryption at rest can protect against cyber-attacks, such as a data breach or unauthorized access, as it makes it difficult for an attacker to extract any useful information from the data.

Encryption at rest is a key measure to protect sensitive information, it’s important to make sure to choose a secure encryption algorithm, and to keep the encryption keys and configuration files secure and backed up in case of disaster recovery scenarios.

How to encrypt Data at Rest in ClickHouse?

Encrypting data at rest in ClickHouse can be done in a few steps:

Step 1: Enable encryption: Enable encryption in the ClickHouse server configuration file by adding the following line:

encryption=1

Step 2: Generate a key: Create an encryption key using the openssl command. The key should be stored in a safe location and protected by a password:

openssl rand -base64 32 > encryption_key.key

Step 3: Create an encryption configuration file: Create an encryption configuration file, specifying the encryption algorithm and key file:

[encryption]
key_file = /path/to/encryption_key.key
algorithm = AES256

Step 4: Modify the table: To encrypt a specific table, modify the table settings to include the ‘encryption’ setting and the location of the encryption configuration file:

ALTER TABLE <table_name>
SETTINGS encryption='/path/to/encryption.conf';

Step 5: Create a new table, To encrypt a new table, include the ‘encryption’ setting and the location of the encryption configuration file in the CREATE TABLE statement:

CREATE TABLE <table_name> (...)
ENGINE = MergeTree()
SETTINGS encryption='/path/to/encryption.conf';

Step 6: Encrypt the data: Insert data into the table as usual. The data will be automatically encrypted before it is written to disk.
It’s important to note that encryption at rest only encrypts data on disk, it doesn’t encrypt data in transit or data in memory. You should use SSL/TLS to encrypt data in transit, and use proper security protocols to protect the data in memory. Also, encryption at rest does have some performance overhead, so it’s important to test the performance of the system before applying it to a production environment.

It’s important to test the system before applying it to a production environment and to keep the encryption key and configuration file secure and backed up, in case of a disaster recovery scenario.

Also, keep in mind that encrypting data at rest doesn’t replace the need for other security measures, it should be used in conjunction with other security measures such as access control, monitoring,

About Shiv Iyer 56 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.