MoneyMorph: Censorship Resistant Rendezvous using Permissionless Cryptocurrencies

AbstractCryptocurrencies play a major role in the global financial ecosystem. Their presence across different geopolitical corridors, including in repressive regimes, has been one of their striking features. In this work, we leverage this feature for bootstrapping Censorship Resistant communication. We conceptualize the notion of stego-bootstrapping scheme and its security in terms of rareness and security against chosencovertext attacks. We present MoneyMorph, a provably secure stego-bootstrapping scheme using cryptocurrencies. MoneyMorph allows a censored user to interact with a decoder entity outside the censored region, through blockchain transactions as rendezvous, to obtain bootstrapping information such as a censorshipresistant proxy and its public key. Unlike the usual bootstrapping approaches (e.g., emailing) with heuristic security, if any, MoneyMorph employs public-key steganography over blockchain transactions to ensure provable cryptographic security. We design rendezvous over Bitcoin, Zcash, Monero, and Ethereum, and analyze their effectiveness in terms of available bandwidth and transaction cost. With its highly cryptographic structure, we show that Zcash provides 1148 byte bandwidth per transaction costing less than 0.01 USD as fee.

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Certificateless Short Signature Scheme from Bilinear Pairings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.380-384.2435 ◽

2013 ◽

Vol 380-384 ◽

pp. 2435-2438 ◽

Cited By ~ 2

Author(s):

Shu Rong Feng ◽

Jiao Mo ◽

Hua Zhang ◽

Zheng Ping Jin

Keyword(s):

Bilinear Pairings ◽

Public Key ◽

Security Level ◽

Signature Scheme ◽

Signature Schemes ◽

Short Signature ◽

Certificateless Signature ◽

Provably Secure

Certificateless short signature schemes can not only have the advantage of certificateless signature, but also provide a short signature size in communication. However, all existing certificateless short signature schemes only proven secure against a normal adversary which can only obtain the valid signature for the original public key rather than a super adversary which can obtain the valid signature for the replaced public key. Recently, Fan et al. proposed a certificateless short signature scheme which is very efficient, but we found it is still cannot against super adversary. In this paper, we first analysis their scheme, and then present an improved scheme which can against super adversaries. Furthermore, our scheme can provide both the strongest security level and the shortest signature size compared the existed provably secure certificateless short signature scheme.

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Yet Another Efficient and Provably-Secure Certificateless Public Key Signature Scheme without Pairing

2010 International Conference on Communications and Mobile Computing ◽

10.1109/cmc.2010.231 ◽

2010 ◽

Author(s):

Liangliang Wang ◽

Mingxing He ◽

Yanyan Zhang

Keyword(s):

Public Key ◽

Signature Scheme ◽

Provably Secure

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A practical public key cryptosystem provably secure against adaptive chosen ciphertext attack

Advances in Cryptology — CRYPTO '98 - Lecture Notes in Computer Science ◽

10.1007/bfb0055717 ◽

1998 ◽

pp. 13-25 ◽

Cited By ~ 644

Author(s):

Ronald Cramer ◽

Victor Shoup

Keyword(s):

Public Key ◽

Public Key Cryptosystem ◽

Chosen Ciphertext Attack ◽

Provably Secure

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Design and Analysis of Fast Provably Secure Public-Key Cryptosystems Based on a Modular Squaring

Information Security and Cryptology — ICISC 2001 - Lecture Notes in Computer Science ◽

10.1007/3-540-45861-1_8 ◽

2002 ◽

pp. 81-102 ◽

Cited By ~ 10

Author(s):

Mototsugu Nishioka ◽

Hisayoshi Satoh ◽

Kouichi Sakurai

Keyword(s):

Public Key ◽

Public Key Cryptosystems ◽

Provably Secure

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Another Attack on Tso's Short Signature Scheme Based on Bilinear Pairings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.63-64.785 ◽

2011 ◽

Vol 63-64 ◽

pp. 785-788

Author(s):

Fan Yu Kong ◽

Lei Wu ◽

Jia Yu

Keyword(s):

Random Oracle Model ◽

Bilinear Pairings ◽

Random Oracle ◽

Public Key ◽

Signature Scheme ◽

Short Signature ◽

Provably Secure

In 2009, R. Tso et al. proposed an efficient pairing-based short signature scheme which is provably secure in the Random Oracle Model. In this paper, we propose a new key substitution attack on Raylin Tso et al.’s short signature scheme. For a given message and the corresponding valid signature, the malicious attacker can generate a substituted public key. Everyone verifies the signature successfully with the malicious attacker’s substituted public key. Therefore, Raylin Tso et al.’s short signature scheme has a security flaw in the multi-user setting.

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Provably Secure Public Key Cryptosystem Based on Chebyshev Polynomials

Journal of Communications ◽

10.12720/jcm.10.6.380-384 ◽

2015 ◽

Author(s):

Shijie Yan ◽

◽

Ping Zhen ◽

Lequan Min

Keyword(s):

Chebyshev Polynomials ◽

Public Key ◽

Public Key Cryptosystem ◽

Provably Secure

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Efficient Convertible User Designating Confirmer Partially Blind Signature with Provable Security

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.282-283.307 ◽

2011 ◽

Vol 282-283 ◽

pp. 307-311

Author(s):

Li Zhen Ma

Keyword(s):

Provable Security ◽

Discrete Logarithm ◽

Random Oracle Model ◽

Random Oracle ◽

Blind Signature ◽

Discrete Logarithm Problem ◽

Public Key ◽

Signature Schemes ◽

Partially Blind Signature ◽

Provably Secure

Any one who knows the signer’s public key can verify the validity of a given signature in partially blind signature schemes. This verifying universality may be used by cheats if the signed message is sensitive or personal. To solve this problem, a new convertible user designating confirmer partially blind signature, in which only the designated confirmer (designated by the user) and the user can verify and confirm the validity of given signatures and convert given signatures into publicly verifiable ones, is proposed. Compared with Huang et al.’s scheme, the signature size is shortened about 25% and the computation quantity is reduced about 36% in the proposed scheme. Under random oracle model and intractability of Discrete Logarithm Problem the proposed scheme is provably secure.

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A Provably Secure Revocable ID-Based Authenticated Group Key Exchange Protocol with Identifying Malicious Participants

The Scientific World JOURNAL ◽

10.1155/2014/367264 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Tsu-Yang Wu ◽

Tung-Tso Tsai ◽

Yuh-Min Tseng

Keyword(s):

Key Exchange ◽

Public Key ◽

Key Exchange Protocol ◽

Forward Secrecy ◽

Group Key ◽

Computation Technique ◽

Group Key Exchange ◽

Security Properties ◽

Authenticated Group Key ◽

Provably Secure

The existence of malicious participants is a major threat for authenticated group key exchange (AGKE) protocols. Typically, there are two detecting ways (passive and active) to resist malicious participants in AGKE protocols. In 2012, the revocable identity- (ID-) based public key system (R-IDPKS) was proposed to solve the revocation problem in the ID-based public key system (IDPKS). Afterwards, based on the R-IDPKS, Wu et al. proposed a revocable ID-based AGKE (RID-AGKE) protocol, which adopted a passive detecting way to resist malicious participants. However, it needs three rounds and cannot identify malicious participants. In this paper, we fuse a noninteractive confirmed computation technique to propose the first two-round RID-AGKE protocol with identifying malicious participants, which is an active detecting way. We demonstrate that our protocol is a provably secure AGKE protocol with forward secrecy and can identify malicious participants. When compared with the recently proposed ID/RID-AGKE protocols, our protocol possesses better performance and more robust security properties.

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