[REPRINT] - SM4

 

Background: Cryptography Standards in China

China has developed its own suite of cryptographic standards, known as the SM (ShangMi) algorithms, to address national security concerns and reduce reliance on foreign technologies. The State Cryptography Administration (SCA) oversees these standards, which are now mandatory in many sectors, especially those involving government, finance, and critical infrastructure. The SM series includes symmetric ciphers, hash functions, and public-key algorithms, with SM4 and SM3 being the most widely adopted for encryption and hashing, respectively.

For more on global cryptography standards, see NIST SP 800-175B.

Overview of SM Algorithms

The SM algorithms are a family of cryptographic primitives designed to meet China’s unique regulatory and security requirements. They include:

• SM2 – Public key cryptography based on elliptic curves
• SM3 – Cryptographic hash function
• SM4 – Block cipher for symmetric encryption

This article focuses on SM4 and SM3, which are now integral to secure communications, data integrity, and compliance in China.

https://www.onlinehashcrack.com/guides/cryptography-algorithms/sm4-sm3-algorithms-china-s-standards-explained.php

 

 

SM4 is a block cipher standard published by the Chinese National Cryptography Administration in 2006 as part of the GB/T 32907-2016 standard. It is the national encryption standard for securing wireless communications (e.g., Wi-Fi) and other secure communication systems within China. SM4 operates on 128-bit data blocks and uses a 128-bit encryption key.

The SM4 algorithm uses 32 rounds of encryption operations based on a combination of non-linear substitution, linear transformation, and key addition. Its structure is similar in some respects to other modern block ciphers, utilizing an S-box for substitution and a linear transformation for diffusion.

SM4 has been officially standardized by ISO/IEC as part of ISO/IEC 18033-3:2010 through Amendment 1, published in 2021. It is widely deployed in government, banking, and commercial applications across China. It is optimized for both software and hardware implementations, providing strong security with relatively high performance.