A Comparative Analysis of SM1, SM4, and AES: Security, Vulnerability, and Performance Evaluation


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In the ever-evolving landscape of cybersecurity, selecting the right encryption algorithm is crucial for safeguarding sensitive information. Three prominent contenders in the encryption arena are SM1, SM4, and AES (Advanced Encryption Standard). This article aims to provide a comprehensive comparison of these encryption algorithms based on their security, vulnerability, and performance characteristics.

What is SM1

SM1 refers to the first encryption algorithm in a series of cryptographic algorithms specified by the Chinese State Cryptography Administration (SCA). The algorithm is part of the Chinese National Standard for Information Security Technology, and it is commonly used for securing data in China.

SM1 employs a block cipher with a block size of 128 bits and a key size of 128 bits. It is used for various cryptographic applications, including data encryption and integrity verification.

The SM1 algorithm is a commercial cryptographic block standard symmetric algorithm compiled by the Chinese State Cryptography Administration. The algorithm is not publicly disclosed; it only exists in the form of IP cores within chips. Chips employing this algorithm can be used in secure products such as smart IC cards, smart cryptographic keys, encryption cards, encryption devices, etc. Simultaneously, it finds wide applications in various fields of electronic government, electronic commerce, and the national economy, including important areas like National e-Government and Police Information Systems.

What is SM4

SM4, also known as SMS4, is a symmetric key block cipher that is part of the Chinese National Standard for cryptographic algorithms. It was released by the Chinese State Cryptography Administration (SCA) and is specified in the standard GB/T 32907-2016. SM4 is often used for various cryptographic applications within China.

Key features of the SM4 algorithm include:

  • Block Size: SM4 operates on blocks of data, and the block size is fixed at 128 bits.
  • Key Size: The key size for SM4 is 128 bits.
  • Rounds: The algorithm employs a fixed number of rounds during its execution. SM4 uses 32 rounds to process the data.
  • Feistel Network Structure: SM4 is based on a Feistel network structure, a specific design commonly used in block ciphers.

SM4 is designed to provide a balance between security and efficiency. It is used in various cryptographic applications such as secure communications, electronic payment systems, and other scenarios where data confidentiality is essential.

Similar to SM1, SM4 is primarily intended for domestic use in China and may not have the same level of international recognition as widely adopted encryption standards like AES. As with any cryptographic algorithm, its security relies on factors such as the key size, the number of rounds, and resistance to various cryptanalytic attacks.

What is AES

AES stands for Advanced Encryption Standard. It is a widely used and globally recognized symmetric encryption algorithm established by the National Institute of Standards and Technology (NIST) in 2001. AES is a symmetric key algorithm, meaning the same key is used for both encryption and decryption of data.

Key features of AES include:

  • Block Cipher: AES operates on fixed-size blocks of data, with a block size of 128 bits.
  • Key Sizes: AES supports key sizes of 128, 192, and 256 bits. The key size determines the strength of the encryption.
  • Rounds: AES performs multiple rounds of processing on the data, with the number of rounds depending on the key size. For 128-bit keys, there are 10 rounds; for 192-bit keys, there are 12 rounds; and for 256-bit keys, there are 14 rounds.
  • Substitution-Permutation Network (SPN) Structure: AES uses a substitution-permutation network, a specific type of cryptographic network structure that involves both substitution and permutation operations.

AES has become the de facto standard for symmetric encryption and is widely used to secure sensitive data, communications, and various applications. It has been extensively studied and analyzed by the cryptographic community, contributing to its reputation as a secure encryption algorithm.


Security is paramount when it comes to encryption algorithms, as their primary purpose is to protect data from unauthorized access. AES, established by the National Institute of Standards and Technology (NIST), is widely recognized for its robust security. It employs key sizes of 128, 192, or 256 bits, providing a high level of resistance against brute-force attacks.

SM1 and SM4, on the other hand, are part of the Chinese National Standard for encryption algorithms. While they are considered secure, the lack of widespread international scrutiny raises questions about their resilience against sophisticated attacks. SM1 employs a 128-bit key, similar to AES, but the extent of its security has not been as rigorously tested on the global stage.

In terms of security, AES currently holds a stronger reputation due to its extensive evaluation and adoption by various organizations worldwide.


There hasn’t been any widely reported or publicly disclosed vulnerability in the SM1 encryption algorithm.

There hasn’t been any widely reported or publicly disclosed vulnerability in the SM4 encryption algorithm.

Vulnerabilities in encryption algorithms can be exploited by malicious actors to compromise the confidentiality of data. As of my knowledge cutoff in January 2022, no major vulnerabilities have been discovered in AES that would significantly compromise its security. The algorithm has withstood extensive cryptanalysis, contributing to its widespread adoption. SM1 and SM4, being less internationally scrutinized, may have potential vulnerabilities yet to be uncovered. It’s important to note that the security landscape is dynamic, and the discovery of vulnerabilities can lead to algorithm adjustments or replacements.


Performance considerations are crucial for the practical implementation of encryption algorithms, especially in resource-constrained environments. AES is known for its efficiency and speed, making it a popular choice for various applications, ranging from securing communications to protecting stored data. SM1 and SM4, while designed with performance in mind, may exhibit variations in efficiency depending on the specific use case. International standardization and widespread adoption of AES have led to optimized implementations and hardware support, contributing to its superior performance in many scenarios.


In the realm of encryption, the choice between SM1, SM4, and AES involves careful consideration of security, vulnerability, and performance factors. AES, having undergone extensive evaluation and global adoption, currently stands as a robust and secure encryption standard. SM1 and SM4, while viable options, may face challenges in gaining international trust and recognition. As the cybersecurity landscape evolves, continuous monitoring of vulnerabilities and advancements in encryption technologies is essential to ensure the protection of sensitive information.