If Bitcoin becomes the prevalent payment system on the Internet, crime fighters will join forces with regulators and enforce blacklisting of transaction prefixes at the parties who offer real products and services in exchange for bitcoin. Blacklisted bitcoins will be hard to spend and therefore less liquid and less valuable. This requires every recipient of Bitcoin payments not only to check al...

In Bitcoin, transaction malleability describes the fact that the signatures that prove the ownership of bitcoins being transferred in a transaction do not provide any integrity guarantee for the signatures themselves. This allows an attacker to mount a malleability attack in which it intercepts, modifies, and rebroadcasts a transaction, causing the transaction issuer to believe that the origina...

Introduction Cryptocurrency investment and trading are rapidly growing activities due to the development of applications platforms that offer fast, continuous, easy entry into cryptocurrency world. To understand decision making in holders, we assessed temporal discounting, is, whether Bitcoin holders disregard rewards if they distant time overvalue more immediate. Further, compared performance ...

© Dunay et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and redistribution in any medium, provided that the original author and source are credited. Bitcoin is a relatively new and attractive asset. It is used for peer-to-peer transactions and is built upon an interesting system calle...

We investigate Bitcoin network monitoring the dynamics of blocks and transactions. We unveil that 43% of the transactions are still not included in the Blockchain after 1h from the first time they were seen in the network and 20% of the transactions are still not included in the Blockchain after 30 days, revealing therefore great inefficiency in the Bitcoin system. However, we observe that most...

Bitcoin exchanges operate between digital and fiat currency networks, thus providing an opportunity to connect real-world identities to pseudonymous addresses, an important task for anti-money laundering efforts. We seek to characterize, understand, and identify patterns centered around exchanges in the context of a directed hypergraph model for Bitcoin transactions. We introduce the idea of mo...

We show how to realize two-factor authentication for a Bitcoin wallet employing the two-party ECDSA signature protocol adapted from MacKenzie & Reiter (2004). We also present a prototypic implementation of a Bitcoin wallet that offers both: two-factor authentication and verification over a separate channel. Since we use a smart phone as the second authentication factor, our solution can be used...

Bitcoin smart contracts allow the development of new protocols on top of Bitcoin itself. This usually involves the definition of complex scripts, far beyond the requirement of a single signature. In this paper we introduce the concept of private key locked transactions, a novel type of transactions that allows the atomic verification of a given private key (belonging to an asymmetric key pair) ...

Bitcoin, the first electronic payment system, is becoming a popular currency. We provide a statistical analysis of the log-returns of the exchange rate of Bitcoin versus the United States Dollar. Fifteen of the most popular parametric distributions in finance are fitted to the log-returns. The generalized hyperbolic distribution is shown to give the best fit. Predictions are given for future va...

Bitcoin is [6] a peer-to-peer distributed currency system. Bitcoin attempts to provide anonymity to users by cycling keys [6] however such protection is of limited value. [8] In this paper I present a new means of forming transactions that prevents a sender of bitcoins from linking the public key of the reciever to a transaction, requiring only a single additional option for what