Tag Archives: cryptocurrency

Using Hacked LastPass Keys to Steal Cryptocurrency

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/09/using-hacked-lastpass-keys-to-steal-cryptocurrency.html

Remember last November, when hackers broke into the network for LastPass—a password database—and stole password vaults with both encrypted and plaintext data for over 25 million users?

Well, they’re now using that data break into crypto wallets and drain them: $35 million and counting, all going into a single wallet.

That’s a really profitable hack. (It’s also bad opsec. The hackers need to move and launder all that money quickly.)

Look, I know that online password databases are more convenient. But they’re also risky. This is why my Password Safe is local only. (I know this sounds like a commercial, but Password Safe is not a commercial product.)

Cryptocurrency Startup Loses Encryption Key for Electronic Wallet

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/09/cryptocurrency-startup-loses-encryption-key-for-electronic-wallet.html

The cryptocurrency fintech startup Prime Trust lost the encryption key to its hardware wallet—and the recovery key—and therefore $38.9 million. It is now in bankruptcy.

I can’t understand why anyone thinks these technologies are a good idea.

Cryptographic Flaw in Libbitcoin Explorer Cryptocurrency Wallet

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/08/cryptographic-flaw-in-libbitcoin-explorer-cryptocurrency-wallet.html

Cryptographic flaws still matter. Here’s a flaw in the random-number generator used to create private keys. The seed has only 32 bits of entropy.

Seems like this flaw is being exploited in the wild.

EDITED TO ADD (8/14): A good explainer.

North Korea Hacking Cryptocurrency Sites with 3CX Exploit

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/04/north-korea-hacking-cryptocurrency-sites-with-3cx-exploit.html

News:

Researchers at Russian cybersecurity firm Kaspersky today revealed that they identified a small number of cryptocurrency-focused firms as at least some of the victims of the 3CX software supply-chain attack that’s unfolded over the past week. Kaspersky declined to name any of those victim companies, but it notes that they’re based in “western Asia.”

Security firms CrowdStrike and SentinelOne last week pinned the operation on North Korean hackers, who compromised 3CX installer software that’s used by 600,000 organizations worldwide, according to the vendor. Despite the potentially massive breadth of that attack, which SentinelOne dubbed “Smooth Operator,” Kaspersky has now found that the hackers combed through the victims infected with its corrupted software to ultimately target fewer than 10 machines­—at least as far as Kaspersky could observe so far—­and that they seemed to be focusing on cryptocurrency firms with “surgical precision.”

Nick Weaver on Regulating Cryptocurrency

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/03/nick-weaver-on-regulating-cryptocurrency.html

Nicholas Weaver wrote an excellent paper on the problems of cryptocurrencies and the need to regulate the space—with all existing regulations. His conclusion:

Regulators, especially regulators in the United States, often fear accusations of stifling innovation. As such, the cryptocurrency space has grown over the past decade with very little regulatory oversight.

But fortunately for regulators, there is no actual innovation to stifle. Cryptocurrencies cannot revolutionize payments or finance, as the basic nature of all cryptocurrencies render them fundamentally unsuitable to revolutionize our financial system—which, by the way, already has decades of successful experience with digital payments and electronic money. The supposedly “decentralized” and “trustless” cryptocurrency systems, both technically and socially, fail to provide meaningful benefits to society—and indeed, necessarily also fail in their foundational claims of decentralization and trustlessness.

When regulating cryptocurrencies, the best starting point is history. Regulating various tokens is best done through the existing securities law framework, an area where the US has a near century of well-established law. It starts with regulating the issuance of new cryptocurrency tokens and related securities. This should substantially reduce the number of fraudulent offerings.

Similarly, active regulation of the cryptocurrency exchanges should offer substantial benefits, including eliminating significant consumer risk, blocking key money-laundering channels, and overall producing a far more regulated and far less manipulated market.

Finally, the stablecoins need basic regulation as money transmitters. Unless action is taken they risk becoming substantial conduits for money laundering, but requiring them to treat all users as customers should prevent this risk from developing further.

Read the whole thing.

Ransomware Payments Are Down

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/01/ransomware-payments-are-down.html

Chainalysis reports that worldwide ransomware payments were down in 2022.

Ransomware attackers extorted at least $456.8 million from victims in 2022, down from $765.6 million the year before.

As always, we have to caveat these findings by noting that the true totals are much higher, as there are cryptocurrency addresses controlled by ransomware attackers that have yet to be identified on the blockchain and incorporated into our data. When we published last year’s version of this report, for example, we had only identified $602 million in ransomware payments in 2021. Still, the trend is clear: Ransomware payments are significantly down.

However, that doesn’t mean attacks are down, or at least not as much as the drastic drop-off in payments would suggest. Instead, we believe that much of the decline is due to victim organizations increasingly refusing to pay ransomware attackers.

Decarbonizing Cryptocurrencies through Taxation

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/01/decarbonizing-cryptocurrencies-through-taxation.html

Maintaining bitcoin and other cryptocurrencies causes about 0.3 percent of global CO2 emissions. That may not sound like a lot, but it’s more than the emissions of Switzerland, Croatia, and Norway combined. As many cryptocurrencies crash and the FTX bankruptcy moves into the litigation stage, regulators are likely to scrutinize the cryptocurrency world more than ever before. This presents a perfect opportunity to curb their environmental damage.

The good news is that cryptocurrencies don’t have to be carbon intensive. In fact, some have near-zero emissions. To encourage polluting currencies to reduce their carbon footprint, we need to force buyers to pay for their environmental harms through taxes.

The difference in emissions among cryptocurrencies comes down to how they create new coins. Bitcoin and other high emitters use a system called “proof of work“: to generate coins, participants, or “miners,” have to solve math problems that demand extraordinary computing power. This allows currencies to maintain their decentralized ledger—the blockchain—but requires enormous amounts of energy.

Greener alternatives exist. Most notably, the “proof of stake” system enables participants to maintain their blockchain by depositing cryptocurrency holdings in a pool. When the second-largest cryptocurrency, Ethereum, switched from proof of work to proof of stake earlier this year, its energy consumption dropped by more than 99.9% overnight.

Bitcoin and other cryptocurrencies probably won’t follow suit unless forced to, because proof of work offers massive profits to miners—and they’re the ones with power in the system. Multiple legislative levers could be used to entice them to change.

The most blunt solution is to ban cryptocurrency mining altogether. China did this in 2018, but it only made the problem worse; mining moved to other countries with even less efficient energy generation, and emissions went up. The only way for a mining ban to meaningfully reduce carbon emissions is to enact it across most of the globe. Achieving that level of international consensus is, to say the least, unlikely.

A second solution is to prohibit the buying and selling of proof-of-work currencies. The European Parliament’s Committee on Economic and Monetary Affairs considered making such a proposal, but voted against it in March. This is understandable; as with a mining ban, it would be both viewed as paternalistic and difficult to implement politically.

Employing a tax instead of an outright ban would largely skirt these issues. As with taxes on gasoline, tobacco, plastics, and alcohol, a cryptocurrency tax could reduce real-world harm by making consumers pay for it.

Most ways of taxing cryptocurrencies would be inefficient, because they’re easy to circumvent and hard to enforce. To avoid these pitfalls, the tax should be levied as a fixed percentage of each proof-of-work-cryptocurrency purchase. Cryptocurrency exchanges should collect the tax, just as merchants collect sales taxes from customers before passing the sum on to governments. To make it harder to evade, the tax should apply regardless of how the proof-of-work currency is being exchanged—whether for a fiat currency or another cryptocurrency. Most important, any state that implements the tax should target all purchases by citizens in its jurisdiction, even if they buy through exchanges with no legal presence in the country.

This sort of tax would be transparent and easy to enforce. Because most people buy cryptocurrencies from one of only a few large exchanges—such as Binance, Coinbase, and Kraken—auditing them should be cheap enough that it pays for itself. If an exchange fails to comply, it should be banned.

Even a small tax on proof-of-work currencies would reduce their damage to the planet. Imagine that you’re new to cryptocurrency and want to become a first-time investor. You’re presented with a range of currencies to choose from: bitcoin, ether, litecoin, monero, and others. You notice that all of them except ether add an environmental tax to your purchase price. Which one do you buy?

Countries don’t need to coordinate across borders for a proof-of-work tax on their own citizens to be effective. But early adopters should still consider ways to encourage others to come on board. This has precedent. The European Union is trying to influence global policy with its carbon border adjustments, which are designed to discourage people from buying carbon-intensive products abroad in order to skirt taxes. Similar rules for a proof-of-work tax could persuade other countries to adopt one.

Of course, some people will try to evade the tax, just as people evade every other tax. For example, people might buy tax-free coins on centralized exchanges and then swap them for polluting coins on decentralized exchanges. To some extent, this is inevitable; no tax is perfect. But the effort and technical know-how needed to evade a proof-of-work tax will be a major deterrent.

Even if only a few countries implement this tax—and even if some people evade it—the desirability of bitcoin will fall globally, and the environmental benefit will be significant. A high enough tax could also cause a self-reinforcing cycle that will drive down these cryptocurrencies’ prices. Because the value of many cryptocurrencies rely largely on speculation, they are dependent on future buyers. When speculators are deterred by the tax, the lack of demand will cause the price of bitcoin to fall, which could prompt more current holders to sell—further lowering prices and accelerating the effect. Declining prices will pressure the bitcoin community to abandon proof of work altogether.

Taxing proof-of-work exchanges might hurt them in the short run, but it would not hinder blockchain innovation. Instead, it would redirect innovation toward greener cryptocurrencies. This is no different than how government incentives for electric vehicles encourage carmakers to improve green alternatives to the internal combustion engine. These incentives don’t restrict innovation in automobiles—they promote it.

Taxing environmentally harmful cryptocurrencies can gain support across the political spectrum, from people with varied interests. It would benefit blockchain innovators and cryptocurrency researchers by shifting focus from environmental harm to beneficial uses of the technology. It has the potential to make our planet significantly greener. It would increase government revenues.

Even bitcoin maximalists have reason to embrace the proposal: it would offer the bitcoin community a chance to prove it can survive and grow sustainably.

This essay was written with Christos Porios, and previously appeared in the Atlantic.

Regulating DAOs

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/regulating-daos.html

In August, the US Treasury’s Office of Foreign Assets Control (OFAC) sanctioned the cryptocurrency platform Tornado Cash, a virtual currency “mixer” designed to make it harder to trace cryptocurrency transactions—and a worldwide favorite money-laundering platform. Americans are now forbidden from using it. According to the US government, Tornado Cash was sanctioned because it allegedly laundered over $7 billion in cryptocurrency, $455 million of which was stolen by a North Korean state-sponsored hacking group.

Tornado Cash is not a traditional company run by human beings, but instead a series of “smart contracts”: self-executing code that exists only as software. Critics argue that prohibiting Americans from using Tornado Cash is a restraint of free speech, pointing to court rulings in the 1990s that established that computer language is a form of language, and that software programs are a form of speech. They also suggest that the Treasury Department has the authority to sanction only humans and not software.

We think that the most useful way to understand the speech issues involved with regulating Tornado Cash and other decentralized autonomous organizations (DAOs) is through an analogy: the golem. There are many versions of the Jewish golem legend, but in most of them, a person-like clay statue comes to life after someone writes the word “truth” in Hebrew on its forehead, and eventually starts doing terrible things. The golem stops only when a rabbi erases one of those letters, turning “truth” into the Hebrew word for “death,” and the golem ceases to function.

The analogy between DAOs and golems is quite precise, and has important consequences for the relationship between free speech and code. Ultimately, just as the golem needed the intervention of a rabbi to stop wreaking havoc on the world, so too do DAOs need to be subject to regulation.

The equivalency of code and free speech was established during the first “crypto wars” of the 1990s, which were about cryptography, not cryptocurrencies. US agencies tried to use export control laws to prevent sophisticated cryptography software from being exported outside the US. Activists and lawyers cleverly showed how code could be transformed into speech and vice versa, turning the source code for a cryptographic product into a printed book and daring US authorities to prevent its export. In 1996, US District Judge Marilyn Hall Patel ruled that computer code is a language, just like German or French, and that coded programs deserve First Amendment protection. That such code is also functional, instructing a computer to do something, was irrelevant to its expressive capabilities, according to Patel’s ruling. However, both a concurring and dissenting opinion argued that computer code also has the “functional purpose of controlling computers and, in that regard, does not command protection under the First Amendment.”

This disagreement highlights the awkward distinction between ordinary language and computer code. Language does not change the world, except insofar as it persuades, informs, or compels other people. Code, however, is a language where words have inherent power. Type the appropriate instructions and the computer will implement them without hesitation, second-guessing, or independence of will. They are like the words inscribed on a golem’s forehead (or the written instructions that, in some versions of the folklore, are placed in its mouth). The golem has no choice, because it is incapable of making choices. The words are code, and the golem is no different from a computer.

Unlike ordinary organizations, DAOs don’t rely on human beings to carry out many of their core functions. Instead, those functions have been translated into a set of instructions that are implemented in software. In the case of Tornado Cash, its code exists as part of Ethereum, a widely used cryptocurrency that can also run arbitrary computer code.

Cryptocurrency zealots thought that DAOs would allow them to place their trust in secure computer code, which would do exactly what they wanted it to do, rather than fallible human beings who might fail or cheat. Humans could still have input, but under rules that were enshrined in self-running software. The past several years of DAO activity has taught these zealots a series of painful and expensive lessons on the limits of both computer security and incomplete contracts: Software has bugs, and contracts may do weird things under unanticipated circumstances. The combination frequently results in multimillion-dollar frauds and thefts.

Further complicating the matter is that individual DAOs can have very different rules. DAOs were supposed to create truly decentralized services that could never turn into a source of state power and coercion. Today, some DAOs talk a big game about decentralization, but provide power to founders and big investors like Andreessen Horowitz. Others are deliberately set up to frustrate outside control. Indeed, the creators of Tornado Cash explicitly wanted to create a golem-like entity that would be immune from law. In doing so, they were following in a long libertarian tradition.

In 2014, Gavin Woods, one of Ethereum’s core developers, gave a talk on what he called “allegality” of decentralized software services. Woods’s argument was very simple. Companies like PayPal employ real people and real lawyers. That meant that “if they provide a service to you that is deemed wrong or illegal … then they get fucked … maybe [go] to prison.” But cryptocurrencies like Bitcoin “had no operator.” By using software running on blockchains rather than people to run your organization, you could do an end-run around normal, human law. You could create services that “cannot be shut down. Not by a court, not by a police force, not by a nation state.” People would be able to set whatever rules they wanted, regardless of what any government prohibited.

Woods’s speech helped inspire the first DAO (The DAO), and his ideas live on in Tornado Cash. Tornado Cash was designed, in its founder’s words, “to be unstoppable.” The way the protocol is “designed, decentralized and autonomous …[,] there’s nobody in charge.” The people who ran Tornado Cash used a decentralized protocol running on the Ethereum computing platform, which is itself radically decentralized. But they used indelible ink. The protocol was deliberately instructed never to accept an update command.

Other elements of Tornado Cash—­its website, and the GitHub repository where its source code was stored—­have been taken down. But the protocol that actually mixes cryptocurrency is still available through the Ethereum network, even if it doesn’t have a user-friendly front end. Like a golem that has been set in motion, it will just keep on going, taking in, processing, and returning cryptocurrency according to its original instructions.

This gets us to the argument that the US government, by sanctioning a software program, is restraining free speech. Not only is it more complicated than that, but it’s complicated in ways that undercut this argument. OFAC’s actions aren’t aimed against free speech and the publication of source code, as its clarifications have made clear. Researchers are not prohibited from copying, posting, “discussing, teaching about, or including open-source code in written publications, such as textbooks.” GitHub could potentially still host the source code and the project. OFAC’s actions are aimed at preventing persons from using software applications that undercut one of the most basic functions of government: regulating activities that it deems endangers national security.

The question is whether the First Amendment covers golems. When your words are used not to persuade or argue, but to animate a mindless entity that will exist as long as the Ethereum blockchain exists and will carry out your final instructions no matter what, should your golem be immune from legal action?

When Patel issued her famous ruling, she caustically dismissed the argument that “even one drop of ‘direct functionality’” overwhelmed people’s expressive rights. Arguably, the question with Tornado Cash is whether a possibly notional droplet of free speech expressivity can overwhelm the direct functionality of running code, especially code designed to refuse any further human intervention. The Tornado Cash protocol will accept and implement the routine commands described by its protocol: It will still launder cryptocurrency. But the protocol itself is frozen.

We certainly don’t think that the US government should ban DAOs or code running on Ethereum or other blockchains, or demand any universal right of access to their workings. That would be just as sweeping—and wrong—as the general claim that encrypted messaging results in a “lawless space,” or the contrary notion that regulating code is always a prior restraint on free speech. There is wide scope for legitimate disagreement about government regulation of code and its legal authorities over distributed systems.

However, it’s hard not to sympathize with OFAC’s desire to push back against a radical effort to undermine the very idea of government authority. What would happen if the Tornado Cash approach to the law prevailed? That is, what would be the outcome if judges and politicians decided that entities like Tornado Cash could not be regulated, on free speech or any other grounds?

Likely, anyone who wanted to facilitate illegal activities would have a strong incentive to turn their operation into a DAO—and then throw away the key. Ethereum’s programming language is Turing-complete. That means, as Woods argued back in 2014, that one could turn all kinds of organizational rules into software, whether or not they were against the law.

In practice, it wouldn’t be so easy. Turning business principles into running code is hard, and doing it without creating bugs or loopholes is much harder still. Ethereum and other blockchains still have hard limits on computing power. But human ingenuity can accomplish many things when there’s a lot of money at stake.

People have legitimate reasons for seeking anonymity in their financial transactions, but these reasons need to be weighed against other harms to society. As privacy advocate Cory Doctorow wrote recently: “When you combine anonymity with finance—­not the right to speak anonymously, but the right to run an investment fund anonymously—you’re rolling out the red carpet for serial scammers, who can run a scam, get caught, change names, and run it again, incorporating the lessons they learned.”

It’s a mistake to defend DAOs on the grounds that code is free speech. Some code is speech, but not all code is speech. And code can also directly affect the world. DAOs, which are in essence autonomous golems, made from code rather than clay, make this distinction especially stark.

This will become even more important as robots become more capable and prevalent. Robots are even more obviously golems than DAOs are, performing actions in the physical world. Should their code enjoy a safe harbor from the law? What if robots, like DAOs, are designed to obey only their initial instructions, however unlawful­—and refuse all further updates or commands? Assuming that code is free speech and only free speech, and ignoring its functional purpose, will at best tangle the law up in knots.

Tying free speech arguments to the cause of DAOs like Tornado Cash imperils some of the important free speech victories that were won in the past. But the risks for everyone might be even greater if that argument wins. A world where democratic governments are unable to enforce their laws is not a world where civic spaces or civil liberties will thrive.

This essay was written with Henry Farrell, and previously appeared on Lawfare.com.

NSA Employee Charged with Espionage

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/nsa-employee-charged-with-espionage.html

An ex-NSA employee has been charged with trying to sell classified data to the Russians (but instead actually talking to an undercover FBI agent).

It’s a weird story, and the FBI affidavit raises more questions than it answers. The employee only worked for the NSA for three weeks—which is weird in itself. I can’t figure out how he linked up with the undercover FBI agent. It’s not clear how much of this was the employee’s idea, and whether he was goaded by the FBI agent. Still, hooray for not leaking NSA secrets to the Russians. (And, almost ten years after Snowden, do we still have this much trouble vetting people before giving them security clearances?)

Mr. Dalke, who had already left the N.S.A. but told the agent that he still worked there on a temporary assignment, then revealed that had taken “highly sensitive information” related to foreign targeting of U.S. systems and information on cyber operations, the prosecutors said. He offered the information in exchange for cryptocurrency and said he was in “financial need.” Court records show he had nearly $84,000 in debt between student loans and credit cards.

EDITED TO ADD (10/5): Marcy Wheeler notes that the FBI seems to be sitting on some common recruitment point, and collecting potential Russian spies.

FBI Seizes Stolen Cryptocurrencies

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/09/fbi-seizes-stolen-cryptocurrencies.html

The Wall Street Journal is reporting that the FBI has recovered over $30 million in cryptocurrency stolen by North Korean hackers earlier this year. It’s only a fraction of the $540 million stolen, but it’s something.

The Axie Infinity recovery represents a shift in law enforcement’s ability to trace funds through a web of so-called crypto addresses, the virtual accounts where cryptocurrencies are stored. These addresses can be created quickly without them being linked to a cryptocurrency company that could freeze the funds.

In its effort to mask the stolen crypto, Lazarus Group used more than 12,000 different addresses, according to Chainalysis. Unlike bank transactions that happen through private networks, movement between crypto accounts is visible to the world on the blockchain.

Advanced blockchain-monitoring tools and cooperation from centralized crypto exchanges enabled the FBI to trace the crypto to where Lazarus Group tried to cash out, investigators said.

The money was laundered through the Tornado Cash mixer.

New Linux Cryptomining Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/09/new-linux-cryptomining-malware.html

It’s pretty nasty:

The malware was dubbed “Shikitega” for its extensive use of the popular Shikata Ga Nai polymorphic encoder, which allows the malware to “mutate” its code to avoid detection. Shikitega alters its code each time it runs through one of several decoding loops that AT&T said each deliver multiple attacks, beginning with an ELF file that’s just 370 bytes.

Shikitega also downloads Mettle, a Metasploit interpreter that gives the attacker the ability to control attached webcams and includes a sniffer, multiple reverse shells, process control, shell command execution and additional abilities to control the affected system.

[…]

The final stage also establishes persistence, which Shikitega does by downloading and executing five shell scripts that configure a pair of cron jobs for the current user and a pair for the root user using crontab, which it can also install if not available.

Shikitega also uses cloud hosting solutions to store parts of its payload, which it further uses to obfuscate itself by contacting via IP address instead of domain name. “Without [a] domain name, it’s difficult to provide a complete list of indicators for detections since they are volatile and they will be used for legitimate purposes in a short period of time,” AT&T said.

Bottom line: Shikitega is a nasty piece of code. AT&T recommends Linux endpoint and IoT device managers keep security patches installed, keep EDR software up to date and make regular backups of essential systems.

Another article.

Slashdot thread.

Responsible Disclosure for Cryptocurrency Security

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/09/responsible-disclosure-for-cryptocurrency-security.html

Stewart Baker discusses why the industry-norm responsible disclosure for software vulnerabilities fails for cryptocurrency software.

Why can’t the cryptocurrency industry solve the problem the way the software and hardware industries do, by patching and updating security as flaws are found? Two reasons: First, many customers don’t have an ongoing relationship with the hardware and software providers that protect their funds­—nor do they have an incentive to update security on a regular basis. Turning to a new security provider or using updated software creates risks; leaving everything the way it was feels safer. So users won’t be rushing to pay for and install new security patches.

Second, cryptocurrency is famously and deliberately decentralized, anonymized, and low friction. That means that the company responsible for hardware or software security may have no way to identify who used its product, or to get the patch to those users. It also means that many wallets with security flaws will be publicly accessible, protected only by an elaborate password. Once word of the flaw leaks, the password can be reverse engineered by anyone, and the legitimate owners are likely to find themselves in a race to move their assets before the thieves do. Even in the software industry, hackers routinely reverse engineer Microsoft’s patches to find the security flaws they fix and then try to exploit them before the patches have been fully installed.

He doesn’t have any good ideas to fix this. I don’t either. Just add it to the pile of blockchain’s many problems.

A Taxonomy of Access Control

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/08/a-taxonomy-of-access-control.html

My personal definition of a brilliant idea is one that is immediately obvious once it’s explained, but no one has thought of it before. I can’t believe that no one has described this taxonomy of access control before Ittay Eyal laid it out in this paper. The paper is about cryptocurrency wallet design, but the ideas are more general. Ittay points out that a key—or an account, or anything similar—can be in one of four states:

safe Only the user has access,
loss No one has access,
leak Both the user and the adversary have access, or
theft Only the adversary has access.

Once you know these states, you can assign probabilities of transitioning from one state to another (someone hacks your account and locks you out, you forgot your own password, etc.) and then build optimal security and reliability to deal with it. It’s a truly elegant way of conceptualizing the problem.

On the Dangers of Cryptocurrencies and the Uselessness of Blockchain

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/06/on-the-dangers-of-cryptocurrencies-and-the-uselessness-of-blockchain.html

Earlier this month, I and others wrote a letter to Congress, basically saying that cryptocurrencies are an complete and total disaster, and urging them to regulate the space. Nothing in that letter is out of the ordinary, and is in line with what I wrote about blockchain in 2019. In response, Matthew Green has written—not really a rebuttal—but a “a general response to some of the more common spurious objections…people make to public blockchain systems.” In it, he makes several broad points:

  1. Yes, current proof-of-work blockchains like bitcoin are terrible for the environment. But there are other modes like proof-of-stake that are not.
  2. Yes, a blockchain is an immutable ledger making it impossible to undo specific transactions. But that doesn’t mean there can’t be some governance system on top of the blockchain that enables reversals.
  3. Yes, bitcoin doesn’t scale and the fees are too high. But that’s nothing inherent in blockchain technology—that’s just a bunch of bad design choices bitcoin made.
  4. Blockchain systems can have a little or a lot of privacy, depending on how they are designed and implemented.

There’s nothing on that list that I disagree with. (We can argue about whether proof-of-stake is actually an improvement. I am skeptical of systems that enshrine a “they who have the gold make the rules” system of governance. And to the extent any of those scaling solutions work, they undo the decentralization blockchain claims to have.) But I also think that these defenses largely miss the point. To me, the problem isn’t that blockchain systems can be made slightly less awful than they are today. The problem is that they don’t do anything their proponents claim they do. In some very important ways, they’re not secure. They don’t replace trust with code; in fact, in many ways they are far less trustworthy than non-blockchain systems. They’re not decentralized, and their inevitable centralization is harmful because it’s largely emergent and ill-defined. They still have trusted intermediaries, often with more power and less oversight than non-blockchain systems. They still require governance. They still require regulation. (These things are what I wrote about here.) The problem with blockchain is that it’s not an improvement to any system—and often makes things worse.

In our letter, we write: “By its very design, blockchain technology is poorly suited for just about every purpose currently touted as a present or potential source of public benefit. From its inception, this technology has been a solution in search of a problem and has now latched onto concepts such as financial inclusion and data transparency to justify its existence, despite far better solutions to these issues already in use. Despite more than thirteen years of development, it has severe limitations and design flaws that preclude almost all applications that deal with public customer data and regulated financial transactions and are not an improvement on existing non-blockchain solutions.”

Green responds: “‘Public blockchain’ technology enables many stupid things: today’s cryptocurrency schemes can be venal, corrupt, overpromised. But the core technology is absolutely not useless. In fact, I think there are some pretty exciting things happening in the field, even if most of them are further away from reality than their boosters would admit.” I have yet to see one. More specifically, I can’t find a blockchain application whose value has anything to do with the blockchain part, that wouldn’t be made safer, more secure, more reliable, and just plain better by removing the blockchain part. I postulate that no one has ever said “Here is a problem that I have. Oh look, blockchain is a good solution.” In every case, the order has been: “I have a blockchain. Oh look, there is a problem I can apply it to.” And in no cases does it actually help.

Someone, please show me an application where blockchain is essential. That is, a problem that could not have been solved without blockchain that can now be solved with it. (And “ransomware couldn’t exist because criminals are blocked from using the conventional financial networks, and cash payments aren’t feasible” does not count.)

For example, Green complains that “credit card merchant fees are similar, or have actually risen in the United States since the 1990s.” This is true, but has little to do with technological inefficiencies or existing trust relationships in the industry. It’s because pretty much everyone who can and is paying attention gets 1% back on their purchases: in cash, frequent flier miles, or other affinity points. Green is right about how unfair this is. It’s a regressive subsidy, “since these fees are baked into the cost of most retail goods and thus fall heavily on the working poor (who pay them even if they use cash).” But that has nothing to do with the lack of blockchain, and solving it isn’t helped by adding a blockchain. It’s a regulatory problem; with a few exceptions, credit card companies have successfully pressured merchants into charging the same prices, whether someone pays in cash or with a credit card. Peer-to-peer payment systems like PayPal, Venmo, MPesa, and AliPay all get around those high transaction fees, and none of them use blockchain.

This is my basic argument: blockchain does nothing to solve any existing problem with financial (or other) systems. Those problems are inherently economic and political, and have nothing to do with technology. And, more importantly, technology can’t solve economic and political problems. Which is good, because adding blockchain causes a whole slew of new problems and makes all of these systems much, much worse.

Green writes: “I have no problem with the idea of legislators (intelligently) passing laws to regulate cryptocurrency. Indeed, given the level of insanity and the number of outright scams that are happening in this area, it’s pretty obvious that our current regulatory framework is not up to the task.” But when you remove the insanity and the scams, what’s left?

EDITED TO ADD: Nicholas Weaver is also adamant about this. David Rosenthal is good, too.

EDITED TO ADD (7/8/2022): This post has been translated into German.

15.3 Million Request-Per-Second DDoS Attack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/05/15-3-million-request-per-second-ddos-attack.html

Cloudflare is reporting a large DDoS attack against an unnamed company “operating a crypto launchpad.”

While this isn’t the largest application-layer attack we’ve seen, it is the largest we’ve seen over HTTPS. HTTPS DDoS attacks are more expensive in terms of required computational resources because of the higher cost of establishing a secure TLS encrypted connection. Therefore it costs the attacker more to launch the attack, and for the victim to mitigate it. We’ve seen very large attacks in the past over (unencrypted) HTTP, but this attack stands out because of the resources it required at its scale.

The attack only lasted 15 seconds. No word on motive. Was this a test? Or was that 15-second delay critical for some other fraud?

News article.

Clever Cryptocurrency Theft

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/04/clever-cryptocurrency-theft.html

Beanstalk Farms is a decentralized finance project that has a majority stake governance system: basically people have proportional votes based on the amount of currency they own. A clever hacker used a “flash loan” feature of another decentralized finance project to borrow enough of the currency to give himself a controlling stake, and then approved a $182 million transfer to his own wallet.

It is insane to me that cryptocurrencies are still a thing.

De-anonymizing Bitcoin

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/04/de-anonymizing-bitcoin.html

Andy Greenberg wrote a long article — an excerpt from his new book — on how law enforcement de-anonymized bitcoin transactions to take down a global child porn ring.

Within a few years of Bitcoin’s arrival, academic security researchers — and then companies like Chainalysis — began to tear gaping holes in the masks separating Bitcoin users’ addresses and their real-world identities. They could follow bitcoins on the blockchain as they moved from address to address until they reached one that could be tied to a known identity. In some cases, an investigator could learn someone’s Bitcoin addresses by transacting with them, the way an undercover narcotics agent might conduct a buy-and-bust. In other cases, they could trace a target’s coins to an account at a cryptocurrency exchange where financial regulations required users to prove their identity. A quick subpoena to the exchange from one of Chainalysis’ customers in law enforcement was then enough to strip away any illusion of Bitcoin’s anonymity.

Chainalysis had combined these techniques for de-anonymizing Bitcoin users with methods that allowed it to “cluster” addresses, showing that anywhere from dozens to millions of addresses sometimes belonged to a single person or organization. When coins from two or more addresses were spent in a single transaction, for instance, it revealed that whoever created that “multi-input” transaction must have control of both spender addresses, allowing Chainalysis to lump them into a single identity. In other cases, Chainalysis and its users could follow a “peel chain” — a process analogous to tracking a single wad of cash as a user repeatedly pulled it out, peeled off a few bills, and put it back in a different pocket. In those peel chains, bitcoins would be moved out of one address as a fraction was paid to a recipient and then the remainder returned to the spender at a “change” address. Distinguishing those change addresses could allow an investigator to follow a sum of money as it hopped from one address to the next, charting its path through the noise of Bitcoin’s blockchain.

Thanks to tricks like these, Bitcoin had turned out to be practically the opposite of untraceable: a kind of honeypot for crypto criminals that had, for years, dutifully and unerasably recorded evidence of their dirty deals. By 2017, agencies like the FBI, the Drug Enforcement Agency, and the IRS’s Criminal Investigation division (or IRS-CI) had traced Bitcoin transactions to carry out one investigative coup after another, very often with the help of Chainalysis.

Stolen Bitcoins Returned

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/12/stolen-bitcoins-returned.html

The US has returned $154 million in bitcoins stolen by a Sony employee.

However, on December 1, following an investigation in collaboration with Japanese law enforcement authorities, the FBI seized the 3879.16242937 BTC in Ishii’s wallet after obtaining the private key, which made it possible to transfer all the bitcoins to the FBI’s bitcoin wallet.

Smart Contract Bug Results in $31 Million Loss

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/12/smart-contract-bug-results-in-31-million-loss.html

A hacker stole $31 million from the blockchain company MonoX Finance , by exploiting a bug in software the service uses to draft smart contracts.

Specifically, the hack used the same token as both the tokenIn and tokenOut, which are methods for exchanging the value of one token for another. MonoX updates prices after each swap by calculating new prices for both tokens. When the swap is completed, the price of tokenIn­that is, the token sent by the user­decreases and the price of tokenOut­or the token received by the user­increases.

By using the same token for both tokenIn and tokenOut, the hacker greatly inflated the price of the MONO token because the updating of the tokenOut overwrote the price update of the tokenIn. The hacker then exchanged the token for $31 million worth of tokens on the Ethereum and Polygon blockchains.

The article goes on to talk about how common these sorts of attacks are. The basic problem is that the code is the ultimate authority — there is no adjudication protocol — so if there’s a vulnerability in the code, there is no recourse. And, of course, there are lots of vulnerabilities in code.

To me, this is reason enough never to use smart contracts for anything important. Human-based adjudication systems are not useless pre-Internet human baggage, they’re vital.