SM2

SM2 is a term that can refer to more than one technology, most notably a Chinese public-key cryptography standard and, in a different field, a U.S. Navy missile system. In the cryptographic sense, SM2 denotes a family of public-key algorithms defined by Chinese national standards for digital signatures, public-key encryption, and key exchange. It is part of the SM (Shangmi) series of cryptographic specifications and is intended to provide Chinese equivalents or alternatives to international standards. The SM2 algorithms are based on elliptic curve cryptography over a prime field and use a defined curve, base point, and order specified by the standard. The SM2 signature algorithm produces a signature from a private key and a message hash, with verification performed using the corresponding public key. SM2 encryption offers public-key encryption with a derived symmetric key, and SM2 key-exchange protocols enable authenticated key agreement. The standard commonly uses the SM3 hash function, with some profiles incorporating the SM4 symmetric cipher for data protection.

SM2 has been adopted in various Chinese government and financial systems and is used in digital certificates, identity verification, and secure communications within national infrastructure. Open-source and commercial cryptographic libraries provide SM2 support, reflecting its integration into Chinese digital security ecosystems. Interoperability with non-Chinese systems may require mappings or compatibility layers due to different parameter choices and conventions.

Other uses of the acronym include the Standard Missile 2 (SM-2), a family of U.S. Navy surface-to-air missiles deployed on Aegis-equipped ships since the 1980s; this is unrelated to the cryptographic SM2.