零知識 受信者 指定 디지틀 署名方式 = Zero-knowledge nominative signature

다국어 초록 (Multilingual Abstract)

The nice concept of undeniable signatures was presented by Chaum and van Antwerpen. Briefly, an undeniable signature is a
signature which cannot be verified without the help of the signer.
They are therefore less personal than ordinary signatures in the sense that a signature cannot be related to the signer without his help. On the other hand, the signer can only repudiate an alleged signature by proving that it is incorrect.
Boyar, Cham, Damgard and Pedersen introduce convertible undeniable signatures. In this schemes, release of a single bit string by the signer turns all of his signatures, which were originally undeniable signatures, into ordinary digital signatures.
In this paper, we propose a new kind of signature scheme, called "nominative signatures", that is the dual scheme of undeniable signatures. Also we construct a zero -knowledge protocol that implements it.
The new technique called "nominatiue signatures" achieves these objectives: Only nominee can verify the nominator(signer)'s signature and if necessary, only nominee can prove to the third party that the signature is issued to him(her) and is valid. Contrary to the undeniable signature scheme, nominative signatures are confirmed via a protocol between the nominee and the third party, so the cooperation of the nominee is necessary. That is, Not a signer(nominator) but verifiednominee) can control the abuse of signatures. - undeniable signature cannot be verified without the cooperation of the signer, so the signer controls the abuse of signatures.
Our nominative signatures is very valuable for the case which the content of signature is concerned with the verifier's privacy.
And, we present an efficient integrated system of nominative signatures and (convertible) undeniable signatures. i.e. we show how nominative signature scheme can be changed into a (convertible) undeniable signatures.

목차 (Table of Contents)

• 목차
• 1 서론 = 1
• 2 계산 복잡도 이론 = 6
• 2.1.개요 = 6
• 2.2.문제와 알고리즘 = 6
• 2.2.1.문제 = 6
• 2.2.2.알고리즘 = 8
• 2.2.3.알고리즘 및 문제의 분석 = 9
• 2.3.계산 모델 = 10
• 2.3.1.확률적 튜링 기계 = 11
• 2.4.계산 복잡도 클래스 = 13
• 2.4.1.클래스 P = 13
• 2.4.2.클래스 NP = 14
• 2.4.3.클래스 BPP = 16
• 3 영지식 대화명 증명방식 = 18
• 3.1.개요 = 18
• 3.2.NP 증명방식 = 19
• 3.3.대화명 증명방식 = 20
• 3.4.영지식 대화명 증명 = 23
• 3.5.언어·지식·계산능력의 영지식 = 24
• 4 부인 방지 서명방식 = 27
• 4.1. 개요 = 27
• 4.2. D.Chaum의 부인 방지 서명방식 = 27
• 5 수신자 지정 서명방식 = 32
• 5.1 개요 = 32
• 5.2.수신자 지정 서명방식의 요구조건 = 33
• 5.3.수신자 지정 서명방식의 형식적인 정의 = 34
• 5.4.영지식 수신자 지정 서명방식 = 37
• 6 통합 시스템 = 43
• 6.1 개요 = 43
• 6.2 통합 시스템 = 43
• 6.2.1 수신자 지정 서명방식 = 45
• 6.2.2 부인 방지 서명 방식 = 45
• 6.2.3 convertible한 부인 방지 서명 방식 = 49
• 7 결론 = 52
• 참고문헌 = 54
• ABSTRACT = 59