What Is Encryption Rules

In a database encryption system, an encryption rule represents a combination of an encryption algorithm and the corresponding encryption mode; configuring an encryption rule is equivalent to selecting an encryption algorithm and employing one of its encryption modes.

Taking the national cryptographic standard SM4 as an example, SM4 supports the following operating modes; each mode has distinct characteristics and security levels. The detailed information is as follows:

• ECB (Electronic Codebook Mode): Each block is encrypted independently; this mode offers lower security and is not recommended for encrypting large amounts of data.
• CBC (Cipher Block Chaining Mode): Uses an initialization vector (IV); the encryption of each block depends on the ciphertext of the preceding block, providing high security.
• CTR (Counter Mode): Transforms a block cipher into a stream cipher, making it suitable for parallel encryption and offering high security.
• CFB (Cipher Feedback): Transforms block encryption into stream encryption, making it suitable for real-time data transmission.
• OFB (Optimized Feedback Logic Stream Cipher Mode): A stream cipher mode utilizing optimized feedback logic.
• GCM (Galois/Counter Mode): A typical AEAD mode.
• CCM (Counter/CBC-MAC Mode): A lightweight AEAD mode.

This product selectively supports the SM4 GCM mode based on encryption security requirements and product specifications.