Researchers set new cryptanalysis world record for pairing-based cryptography

923-bit encryption key was cracked in 148 days, researchers from Japan say

Researchers from Fujitsu Laboratories, Japan's National Institute of Information and Communications Technology (NICT) and Kyushu University have set a new cryptanalysis world record by cracking a 278-digit-long (923-bit) key used in a pairing-based cryptography system, Japanese IT services provider Fujitsu said Monday.

The cryptanalysts who worked on this project cracked the 923-bit encryption key in 148.2 days by using 21 computers with a total of 252 cores. It had been previously estimated that pairing-based cryptography of this length would require several hundred thousand years to break, the researchers said.

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The previous record dated from 2009 when researchers from NICT and Japan's Hakodate Future University cracked a 204-digit-long (676-bits) key. Cracking a 923-bit key was hundreds of times more difficult.

The researchers explained that they overcame this problem by using several new technologies, including optimization techniques, a new two-dimensional search algorithm and parallel programming.

Pairing-based cryptography (PBC) can be used for identity-based encryption, keyword searchable encryption and other applications for which traditional public key cryptography is unsuitable.

PBC has been very attractive for cryptographers since 2000, when it was used to develop a one-round three-party key agreement protocol as an alternative to the two-round three-party Diffie-Hellman key exchange. However, being a novelty in the cryptographic world, its security has not been thoroughly studied.

The researchers hope that their cryptanalysis effort will help standardizing organizations and governments determine what role PBC will play in developing the next-generation cryptography standards and what is the appropriate key length to use with this type of encryption going forward.

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