- Seigo Arita, Kazuto Matsuo, Koh-ichi Nagao, and Mahoro Shimura, A Weil descent attack against elliptic curve cryptosystems over quartic extension fields, IEICE Trans. Fundamentals E89-A (2006), no. 5, 28.
- Koh-ichi Nagao, Decomposed attack for the jacobian of a hyperelliptic curve over an extension field, IACR (2007), 15 pages.[eprint]