SM4

SM4, Sm4 or SM-4 may refer to:

Technology and engineering

• SM4 (cipher), a block cipher used in the Chinese National Standard
• SM-4, minicomputer
• VR Class Sm4, a type of train operated by the VR Group
• HST-SM4, the final servicing mission to the Hubble Space Telescope
• Standard Missile 4, a missile

Other uses

• SM4 (classification), a swimming classification
• SM4, a part of the SM postcode area, in Sutton, England