1,354,404 research outputs found
Ring Signature Confidential Transactions for Monero
No full textThis article introduces a method of hiding transaction amounts in
the strongly decentralized anonymous cryptocurrency Monero. Similar
to Bitcoin, Monero is a cryptocurrency which is distributed through
a proof of work ``mining\u27\u27 process. The original Monero protocol
was based on CryptoNote, which uses ring signatures and one-time keys
to hide the destination and origin of transactions. Recently the technique
of using a commitment scheme to hide the amount of a transaction has
been discussed and implemented by Bitcoin Core Developer Gregory Maxwell.
In this article, a new type of ring signature, A Multi-layered Linkable
Spontaneous Anonymous Group signature is described which allows for hidden
amounts, origins and destinations of transactions with reasonable
efficiency and verifiable, trustless coin generation. The author would like to note that early drafts of this were publicized in the Monero Community and on the bitcoin research irc channel. Blockchain hashed drafts are available in \cite{Snoe}
PayMo: Payment Channels For Monero
No full textDecentralized cryptocurrencies still suffer from three interrelated weaknesses: Low transaction rates, high transaction fees, and long
confirmation times. Payment Channels promise to be a solution to these issues, and many constructions for real-life cryptocurrencies,
such as Bitcoin, are known. Somewhat surprisingly, no such solution is known for Monero, the largest privacy-preserving cryptocurrency,
without requiring system-wide changes like a hard-fork of its blockchain.
In this work, we close this gap by presenting \textsc{PayMo}, the first payment channel protocol that is fully compatible with Monero.
\textsc{PayMo} does not require any modification of Monero and can be readily used to perform off-chain payments. Notably, transactions in \textsc{PayMo} are identical to standard transactions in Monero, therefore not hampering the coins\u27 fungibility. Using \textsc{PayMo}, we also construct the first fully compatible secure atomic-swap protocol for Monero: One can now securely swap a token of Monero with a token of several major cryptocurrencies such as Bitcoin, Ethereum,
Ripple, Cardano, etc. Before our work, it was not known how to implement secure atomic swaps protocols for Monero without forcing a hard fork.
Our main technical contribution is a new construction of an efficient verifiable timed linkable ring signature, where signatures can be hidden for a pre-determined amount of time, in a verifiable way. Our scheme is fully compatible with the transaction scheme of Monero and it might be of independent interest.
We implemented \textsc{PayMo} and our results show that, even with high network latency and with a single CPU core, two regular users can perform up to 93500 payments over a span of 2 minutes (the block production rate of Monero). This is approximately five orders of magnitude improvement over the current payment rate of Monero
Network analysis and traceability on monero blockchain
No full textMonero was introduced as a privacy-focused alternative to Bitcoin in 2014. Based on privacy enhancing features such as ring signatures, stealth addresses and RingCT, it is supposed to protect the privacy of users while still solving the issue of double spending, which is rare in crypto currency. However, Monero is not foolproof when it comes to privacy, as previous studies have shown that it is vulnerable to weakness such as the 0-mixin attack. In this study, we explore just how much of Monero transactions are traceable, using previously known exploits to de-anonymize Monero inputs. The end goal of this study is to show that Monero is not as untraceable as thought to be, and that for Monero to achieve its privacy goals, it has to enforce privacy-by-default measures, such as using a minimum number of mixins.Bachelor of Engineering (Computer Science
Anonymity Reduction Attacks to Monero
No full textMonero is one of the most valuable cryptocurrencies in the market, focusing on users’ privacy. The built-in features in Monero help users to obfuscate the information of the senders and the receivers, hence achieve a better privacy compared to other cryptocurrencies such as Bitcoin. Previous studies discovered multiple problems within Monero systems, and based on these findings, Monero system has been improved. Although improvements have been made, we discovered that new attacks targeting the anonymity reduction can still be conducted in Monero system. In this paper we propose two attacks. The first is an extension of a known attack called Monero Ring Attack. The second one exploits Payment ID to discover the real output of a mixin. We then propose countermeasures to these attacks
Monero Mining: CryptoNight Analysis
No full textΤο κρυπτονόμισμα Bitcoin αποτελεί την πρώτη πετυχημένη εφαρμογή της ιδέας του ηλεκτρονικού χρήματος χωρίς την διαμεσολάβηση τρίτων. Στην πορεία, πολλά κρυπτο- νομίσματα βασίστηκαν στην συγκεκριμένη τεχνολογία, εστιάζοντας το καθένα στους δικούς του στόχους και σκοπούς. Το κρυπτονόμισμα Monero είναι ένα τέτοιο εγχείρημα, βασικός σκοπός του οποίου είναι η διασφάλιση της ιδιωτικότητας και της ανωνυμίας. Σε έναν κόσμο όπου η παρακολούθηση εντείνεται, το εγχείρημα του Monero σημαίνει τον συναγερμό για την διαρκή καταπάτηση ενός εκ των θεμελιωδών ανθρώπινων δικαιωμάτων. Επιπλέον, καθώς οι επιχειρήσεις έχουν περιορίσει δραματικά τον υγιή ανταγωνισμό σχεδόν σε όλα τα διαδεδομένα κρυπτονομίσματα, το Monero προσπαθεί να τον διατηρήσει στην κοινότητά του. Ένα από τα δομικά στοιχεία του Monero είναι η διατήρηση της ισότητας μεταξύ των "ανθρακωρύχων" (miners), η οποία επιτυγχάνεται μέσω της ισονομίας (egalitarianism). Η ισονομία είναι συνέπεια μιας ιδιότητας της κρυπτογραφικής συνάρτησης που χρησιμοποιείται για την "εξόρυξη" νομισμάτων. Η συνάρτηση που χρησιμοποιείται στο Monero για αυτόν τον σκοπό λέγεται CryptoNight και είναι μέρος του CryptoNote πρωτοκόλλου. Το στοιχείο της συνάρτησης που επιτυγχάνει την ισονομία είναι μια κρυπτογραφική ιδιότητα, η οποία ονομάζεται memory-hardness. Η CryptoNight συνάρ- τηση θεωρείται ότι διαθέτει αυτήν την ιδιότητα. Όμως, μέχρι σήμερα αυτό παραμένει ισχυρισμός. Απ' όσο γνωρίζουμε, δεν υπάρχει μαθηματική απόδειξη για αυτόν τον ισχυρισμό αλλά ούτε και κάποια επίθεση που να τον διαψεύδει. Θέλοντας να ελέγξουμε την ορθότητα αυτού του ισχυρισμού, προσπαθήσαμε να κατασκευάσουμε μια μαθηματική απόδειξη. Αναφέρουμε τους λόγους για τους οποίους αποτυγχάνουμε να διατυπώσουμε μία τέτοια απόδειξη και προσπαθούμε να τους χρησι- μοποιήσουμε για να καταρρίψουμε αυτόν τον ισχυρισμό. Απ' όσο γνωρίζουμε, η παρού- σα εργασία είναι η πρώτη που μελετά αυτήν την ιδιότητα για την συνάρτηση CryptoNight και παρουσιάζεται για πρώτη φορά γραφικά η εσωτερική δομή της. Τέλος, παρουσιάζουμε την γνώση που αποκτήσαμε και ελπίζουμε αυτή η εργασία να φανεί χρήσιμη μελλοντικά σε συναδέλφους που θέλουν να συμβάλλουν στην έρευνα στο ευρύτερο πεδίο. Στόχος αυτής της έρευνας είναι να συνεισφέρει στην προσπάθεια του εγχειρήματος Monero για την διασφάλιση της ιδιωτικότητας, της ανωνυμίας και της ισότητας.Bitcoin has been a successful implementation of the concept of peer-to-peer electronic cash. Based on this technology several cryptocurrency projects have arisen, each one focusing on its purposes and goals. Monero is a decentralized cryptocurrency focusing on privacy and anonymity. In a world of surveillance, Monero raises the alarm about one of the fundamental human rights, which is continuously violated: Privacy. In addition, Monero is built to achieve equality between miners. Corporations are taking over almost every successful cryptocurrency, by making mining participation harder and harder for the hobbyists and supporters. Monero tries to keep its community clean of unhealthy competition. This is achieved through egalitarianism, which is based οn a cryptographic mining function. This function is called CryptoNight and is part of the CryptoNote protocol, the heart of Monero's structure. The feature of this function that makes it egalitarian is a cryptographic property, named memory-hardness. CryptoNight is alleged to be memory-hard. But, still today, this is just a claim. We put to the test this claim, trying to construct a formal mathematical proof, but we fail to do so. We discuss the reasons for our failure and try to use them to construct an attack on this feature. To our knowledge, we are the first to study this CryptoNight's property and the first to present graphically all the stages of CryptoNight's functionality. Finally, we present the knowledge gained and wish for this document to be useful in the future to colleagues that want to contribute in this field. The aim of this work is to contribute to Monero's fight for privacy, anonymity and equality
Anonymity reduction attacks to Monero
No full text© 2019, Springer Nature Switzerland AG. Monero is one of the most valuable cryptocurrencies in the market, focusing on users’ privacy. The built-in features in Monero help users to obfuscate the information of the senders and the receivers, hence achieve a better privacy compared to other cryptocurrencies such as Bitcoin. Previous studies discovered multiple problems within Monero systems, and based on these findings, Monero system has been improved. Although improvements have been made, we discovered that new attacks targeting the anonymity reduction can still be conducted in Monero system. In this paper we propose two attacks. The first is an extension of a known attack called Monero Ring Attack. The second one exploits Payment ID to discover the real output of a mixin. We then propose countermeasures to these attacks
Monero: Public Keys of spent TXOs
No full textMonero's untraceability is based on the sampling of decoy inputs for each real transaction input. If a decoy input is a reference to an output which is known to be spent, it does not contribute to the size of the anonymity set of the real input. To prevent the sampling of spent outputs as decoys, the blackballing tool (released together with Monero v.0.12) can be used.
This data set provides a list of public keys which should be avoided as mixins. It consists of the following three files:
Monero TX outputs which are known to be spent (spent_outputs.csv)
Monero TX outputs which are at risk of being identified as spent, due to occuring in a ring with only 2 or 3 possible inputs (risky_outputs.csv)
Monero TX outputs which may have been spent on either the MoneroV or the Monero Original blockchain and are therefore at a higher risk to be identified. (referenced_on_fork.csv
Traceable Monero: Anonymous Cryptocurrency with Enhanced Accountability
No full textMonero provides a high level of anonymity for both users and their transactions. However, many criminal activities might be committed with the protection of anonymity in cryptocurrency transactions. Thus, user accountability (or traceability) is also important in Monero transactions, which is unfortunately lacking in the current literature. In this paper, we fill this gap by introducing a new cryptocurrency named Traceable Monero to balance the user anonymity and accountability. Our framework relies on a tracing authority, but is optimistic, in that it is only involved when investigations in certain transactions are required. We formalize the system model and security model of Traceable Monero. We present a detailed construction of Traceable Monero by overlaying Monero with two types of tracing mechanisms, tracing the one-Time addresses with money flows and tracing the long-Term addresses. We prove the security of Traceable Monero and implement a prototype of the system, which demonstrates that Traceable Monero incurs merely a very small overhead in generating and verifying a transaction compared to Monero transactions
Coinhive's monero drive-by crypto-jacking
No full textThis paper provides study of behaviour on a drive-by crypto-jacking, specifically Coinhive’s Monero. Crypto-jacking is a form of cyber threat where a host machine’s processing power hijacked thru infected website to solve cryptographic puzzles as an unwitting participant. The sample study share host machine and network behaviours when host visited websites that have been embedded with Coinhive’s Monero related script. These data collection of behaviour can be utilize to identify and detect Coinhive’s Monero mining activities in networks
On the unforkability of monero
No full text© 2019 Association for Computing Machinery. Monero, ranked as one of the top privacy-preserving cryptocurrencies by market cap, introduced semi-annual hard fork in 2018. Although hard fork is not an uncommon event in the cryptocurrency industry, the two hard forks in 2018 caused an anonymity risk to Monero where transactions became traceable due to the problem of key reuse. This problem was triggered by the existence of multiple copies of the same coin on different Monero blockchain branches such that the users spent the coins multiple times without preemptive action. We investigate the Monero hard fork events by analysing the transaction data on three different branches of the Monero blockchain. Although we have discovered an insignificant portion of traceable inputs compared to the total available inputs in our dataset, our analyses show that the scalability of the event depends on external factors such as market price and market availability. We propose a cheap, easy to implement strategy to prevent the problem of key reuse, should in the future stronger Monero forks emerge in the market
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