著者

SeongHan SHIN Shota YAMADA Goichiro HANAOKA Yusuke ISHIDA Atsushi KUNII Junichi OKETANI Shimpei KUNII Kiyoshi TOMOMURA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

vol.E105-A, no.8, pp.1121-1133, 2022-08-01

被引用文献数

1

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AONT (All-or-Nothing Transform) is a kind of (n, n)-threshold secret sharing scheme that distributes a message m into a set of n shares such that the message m can be reconstructed if and only if n shares are collected. At CRYPTO 2000, Desai proposed a simple and faster AONT based on the CTR mode of encryption (called CTRT) and proved its security in the ideal cipher model. Though AES-128, whose key length k = 128 and block length l = 128, can be used in CTRT as a block cipher, AES-256 and AES-192 cannot be used due to its intrinsic restriction of k ≤ l. In this paper, we propose an extended CTRT (for short, XCTRT) suitable for AES-256. By thoroughly evaluating all the tricky cases, we prove that XCTRT is secure in the ideal cipher model under the same CTRT security definition. Also, we discuss the security result of XCTRT in concrete parameter settings. For more flexibility of key length, we propose a variant of XCTRT dealing with l<k ≤ 2l by slightly modifying the construction of the last block. After showing implementation details and performance evaluation of CTRT, XCTRT, and the variant, we can say that our XCTRT and its variant have high-speed encoding and decoding performance and are quite practical enough to be deployed in real-world applications.

著者

YUSUKE ISHIDA YOSHINOBU OKABE HIDENORI TOKUYASU RYOHEI KAJI GEN SUGIYAMA TOMOYUKI USHIJIMA YU SASAKI MAKIKO YASUMOTO KEI KURAOKA OSAMU TSURUTA MICHIO SATA

出版者

久留米大学医学部

雑誌

The Kurume Medical Journal (ISSN:00235679)

巻号頁・発行日

vol.60, no.2, pp.67-70, 2013-05-31 (Released:2014-04-14)

参考文献数

6

被引用文献数

3 10

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Ampullary tumors are diagnosed by endoscopic biopsy of the ampulla of Vater. We encountered a rare case of acute pancreatitis following endoscopic biopsy of the ampulla. A 53-year-old man referred to our hospital for detailed examination of a suspected tumor of the ampulla of Vater. We conducted endoscopic biopsy from the ampulla. He developed severe abdominal pain four hours after the procedure. The serum amylase and serum lipase were elevated and abdominal computed tomography (CT) revealed pancreatic enlargement and diffuse stranding of the peri-pancreatic fat, compatible with the findings of acute pancreatitis. We diagnosed the patient as having acute pancreatitis caused by endoscopic biopsy of the ampulla of Vater. Conservative therapy improved his condition, however, a large pancreatic walled-off necrosis (WON) developed. Therefore, we performed endoscopic ultrasonography (EUS)-guided cyst drainage on the 74th day after admission. The WON diminished gradually in size and the symptoms disappeared, and the patient was discharged in good physical condition on the 137th day after admission. In this case, the ampullary biopsy may have caused mucosal edema or intraductal hematoma, resulting in pancreatic duct obstruction. It is important for endoscopists both to be aware of this potential complication following endoscopic biopsy of the ampulla and to inform the patients about possible complications of this procedure.