In cryptography, MISTY1 (or MISTY-1) is a block cipher designed in 1995 by Mitsuru Matsui and others for Mitsubishi Electric. MISTY1 is one of the selected algorithms in the European NESSIE project, and has been recommended for Japanese government use by the CRYPTREC project. KASUMI is a strengthened version of the MISTY1 cipher and has been adopted as the standard encryption algorithm for European mobile phones. In 2005, KASUMI was broken, but there is no practical attack against it yet; see the article for more details.
"MISTY" can stand for "Mitsubishi Improved Security Technology", it is also the initials of the researchers involved in its development: Matsui Mitsuru, Ichikawa Tetsuya, Sorimachi Toru, Tokita Toshio, and Yamagishi Atsuhiro
MISTY1 is covered by patents, although the algorithm is freely available for academic (non-profit) use. RFC 2994.
In the paper "Block Ciphers and Stream Ciphers" by Alex Biryukov, it is noted that KASUMI, also termed A5/3, is a strengthened version of block cipher MISTY1 running in a Counter mode.
US Patent Issued to Fujitsu on Dec. 18 for "Encryption Device, Encryption Method and Storage Medium Storing Its Program" (Japanese Inventors)
Dec 21, 2012; ALEXANDRIA, Va., Dec. 21 -- United States Patent no. 8,335,313, issued on Dec. 18, was assigned to Fujitsu Ltd. (Kawasaki,...