	US 11,888,968 B2
	Signature device, verification device, signature method, verification method, and computer readable medium
Katsuyuki Takashima, Tokyo (JP); Tatsuaki Okamoto, Tokyo (JP); and Pratish Datta, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP); and NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Filed by Mitsubishi Electric Corporation, Tokyo (JP); and NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Filed on Jul. 22, 2021, as Appl. No. 17/382,884.
Application 17/382,884 is a continuation of application No. PCT/JP2019/047995, filed on Dec. 9, 2019.
Claims priority of application No. 2019-048622 (JP), filed on Mar. 15, 2019.
Prior Publication US 2021/0359848 A1, Nov. 18, 2021
Int. Cl. H04L 9/08 (2006.01); G06F 17/16 (2006.01); H04L 9/32 (2006.01)

CPC H04L 9/0825 (2013.01) [G06F 17/16 (2013.01); H04L 9/0861 (2013.01); H04L 9/3247 (2013.01)]

13 Claims

1. A signature device comprising:

processing circuitry to:

acquire a signature key in which an attribute vector is set over a basis B* of a basis B and the basis B*, which are dual bases in dual vector spaces,

generate a signature for a message by setting predicate information of arithmetic branching programs (ABP) for the acquired signature key, and

output the generated signature and the message,

wherein the signature key includes elements respectively corresponding to elements of the attribute vector, and in each of the element of the signature key, index information I* associated with a corresponding one of the elements of the attribute vector is set as a coefficient of one or more but not all basis vectors in the basis B*.