Tag Archives: academicpapers

Human Rights by Design

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/12/human_rights_by.html

Good essay: “Advancing Human-Rights-By-Design In The Dual-Use Technology Industry,” by Jonathon Penney, Sarah McKune, Lex Gill, and Ronald J. Deibert:

But businesses can do far more than these basic measures. They could adopt a “human-rights-by-design” principle whereby they commit to designing tools, technologies, and services to respect human rights by default, rather than permit abuse or exploitation as part of their business model. The “privacy-by-design” concept has gained currency today thanks in part to the European Union General Data Protection Regulation (GDPR), which requires it. The overarching principle is that companies must design products and services with the default assumption that they protect privacy, data, and information of data subjects. A similar human-rights-by-design paradigm, for example, would prevent filtering companies from designing their technology with features that enable large-scale, indiscriminate, or inherently disproportionate censorship capabilities­ — like the Netsweeper feature that allows an ISP to block entire country top level domains (TLDs). DPI devices and systems could be configured to protect against the ability of operators to inject spyware in network traffic or redirect users to malicious code rather than facilitate it. And algorithms incorporated into the design of communications and storage platforms could account for human rights considerations in addition to business objectives. Companies could also join multi-stakeholder efforts like the Global Network Initiative (GNI), through which technology companies (including Google, Microsoft, and Yahoo) have taken the first step toward principles like transparency, privacy, and freedom of expression, as well as to self-reporting requirements and independent compliance assessments.

Propaganda and the Weakening of Trust in Government

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/11/propaganda_and_.html

On November 4, 2016, the hacker “Guccifer 2.0,: a front for Russia’s military intelligence service, claimed in a blogpost that the Democrats were likely to use vulnerabilities to hack the presidential elections. On November 9, 2018, President Donald Trump started tweeting about the senatorial elections in Florida and Arizona. Without any evidence whatsoever, he said that Democrats were trying to steal the election through “FRAUD.”

Cybersecurity experts would say that posts like Guccifer 2.0’s are intended to undermine public confidence in voting: a cyber-attack against the US democratic system. Yet Donald Trump’s actions are doing far more damage to democracy. So far, his tweets on the topic have been retweeted over 270,000 times, eroding confidence far more effectively than any foreign influence campaign.

We need new ideas to explain how public statements on the Internet can weaken American democracy. Cybersecurity today is not only about computer systems. It’s also about the ways attackers can use computer systems to manipulate and undermine public expectations about democracy. Not only do we need to rethink attacks against democracy; we also need to rethink the attackers as well.

This is one key reason why we wrote a new research paper which uses ideas from computer security to understand the relationship between democracy and information. These ideas help us understand attacks which destabilize confidence in democratic institutions or debate.

Our research implies that insider attacks from within American politics can be more pernicious than attacks from other countries. They are more sophisticated, employ tools that are harder to defend against, and lead to harsh political tradeoffs. The US can threaten charges or impose sanctions when Russian trolling agencies attack its democratic system. But what punishments can it use when the attacker is the US president?

People who think about cybersecurity build on ideas about confrontations between states during the Cold War. Intellectuals such as Thomas Schelling developed deterrence theory, which explained how the US and USSR could maneuver to limit each other’s options without ever actually going to war. Deterrence theory, and related concepts about the relative ease of attack and defense, seemed to explain the tradeoffs that the US and rival states faced, as they started to use cyber techniques to probe and compromise each others’ information networks.

However, these ideas fail to acknowledge one key differences between the Cold War and today. Nearly all states — whether democratic or authoritarian — are entangled on the Internet. This creates both new tensions and new opportunities. The US assumed that the internet would help spread American liberal values, and that this was a good and uncontroversial thing. Illiberal states like Russia and China feared that Internet freedom was a direct threat to their own systems of rule. Opponents of the regime might use social media and online communication to coordinate among themselves, and appeal to the broader public, perhaps toppling their governments, as happened in Tunisia during the Arab Spring.

This led illiberal states to develop new domestic defenses against open information flows. As scholars like Molly Roberts have shown, states like China and Russia discovered how they could "flood" internet discussion with online nonsense and distraction, making it impossible for their opponents to talk to each other, or even to distinguish between truth and falsehood. These flooding techniques stabilized authoritarian regimes, because they demoralized and confused the regime’s opponents. Libertarians often argue that the best antidote to bad speech is more speech. What Vladimir Putin discovered was that the best antidote to more speech was bad speech.

Russia saw the Arab Spring and efforts to encourage democracy in its neighborhood as direct threats, and began experimenting with counter-offensive techniques. When a Russia-friendly government in Ukraine collapsed due to popular protests, Russia tried to destabilize new, democratic elections by hacking the system through which the election results would be announced. The clear intention was to discredit the election results by announcing fake voting numbers that would throw public discussion into disarray.

This attack on public confidence in election results was thwarted at the last moment. Even so, it provided the model for a new kind of attack. Hackers don’t have to secretly alter people’s votes to affect elections. All they need to do is to damage public confidence that the votes were counted fairly. As researchers have argued, “simply put, the attacker might not care who wins; the losing side believing that the election was stolen from them may be equally, if not more, valuable.”

These two kinds of attacks — “flooding” attacks aimed at destabilizing public discourse, and “confidence” attacks aimed at undermining public belief in elections — were weaponized against the US in 2016. Russian social media trolls, hired by the “Internet Research Agency,” flooded online political discussions with rumors and counter-rumors in order to create confusion and political division. Peter Pomerantsev describes how in Russia, “one moment [Putin’s media wizard] Surkov would fund civic forums and human rights NGOs, the next he would quietly support nationalist movements that accuse the NGOs of being tools of the West.” Similarly, Russian trolls tried to get Black Lives Matter protesters and anti-Black Lives Matter protesters to march at the same time and place, to create conflict and the appearance of chaos. Guccifer 2.0’s blog post was surely intended to undermine confidence in the vote, preparing the ground for a wider destabilization campaign after Hillary Clinton won the election. Neither Putin nor anyone else anticipated that Trump would win, ushering in chaos on a vastly greater scale.

We do not know how successful these attacks were. A new book by John Sides, Michael Tesler and Lynn Vavreck suggests that Russian efforts had no measurable long-term consequences. Detailed research on the flow of news articles through social media by Yochai Benker, Robert Farris, and Hal Roberts agrees, showing that Fox News was far more influential in the spread of false news stories than any Russian effort.

However, global adversaries like the Russians aren’t the only actors who can use flooding and confidence attacks. US actors can use just the same techniques. Indeed, they can arguably use them better, since they have a better understanding of US politics, more resources, and are far more difficult for the government to counter without raising First Amendment issues.

For example, when the Federal Communication Commission asked for comments on its proposal to get rid of “net neutrality,” it was flooded by fake comments supporting the proposal. Nearly every real person who commented was in favor of net neutrality, but their arguments were drowned out by a flood of spurious comments purportedly made by identities stolen from porn sites, by people whose names and email addresses had been harvested without their permission, and, in some cases, from dead people. This was done not just to generate fake support for the FCC’s controversial proposal. It was to devalue public comments in general, making the general public’s support for net neutrality politically irrelevant. FCC decision making on issues like net neutrality used to be dominated by industry insiders, and many would like to go back to the old regime.

Trump’s efforts to undermine confidence in the Florida and Arizona votes work on a much larger scale. There are clear short-term benefits to asserting fraud where no fraud exists. This may sway judges or other public officials to make concessions to the Republicans to preserve their legitimacy. Yet they also destabilize American democracy in the long term. If Republicans are convinced that Democrats win by cheating, they will feel that their own manipulation of the system (by purging voter rolls, making voting more difficult and so on) are legitimate, and very probably cheat even more flagrantly in the future. This will trash collective institutions and leave everyone worse off.

It is notable that some Arizonan Republicans — including Martha McSally — have so far stayed firm against pressure from the White House and the Republican National Committee to claim that cheating is happening. They presumably see more long term value from preserving existing institutions than undermining them. Very plausibly, Donald Trump has exactly the opposite incentives. By weakening public confidence in the vote today, he makes it easier to claim fraud and perhaps plunge American politics into chaos if he is defeated in 2020.

If experts who see Russian flooding and confidence measures as cyberattacks on US democracy are right, then these attacks are just as dangerous — and perhaps more dangerous — when they are used by domestic actors. The risk is that over time they will destabilize American democracy so that it comes closer to Russia’s managed democracy — where nothing is real any more, and ordinary people feel a mixture of paranoia, helplessness and disgust when they think about politics. Paradoxically, Russian interference is far too ineffectual to get us there — but domestically mounted attacks by all-American political actors might.

To protect against that possibility, we need to start thinking more systematically about the relationship between democracy and information. Our paper provides one way to do this, highlighting the vulnerabilities of democracy against certain kinds of information attack. More generally, we need to build levees against flooding while shoring up public confidence in voting and other public information systems that are necessary to democracy.

The first may require radical changes in how we regulate social media companies. Modernization of government commenting platforms to make them robust against flooding is only a very minimal first step. Up until very recently, companies like Twitter have won market advantage from bot infestations — even when it couldn’t make a profit, it seemed that user numbers were growing. CEOs like Mark Zuckerberg have begun to worry about democracy, but their worries will likely only go so far. It is difficult to get a man to understand something when his business model depends on not understanding it. Sharp — and legally enforceable — limits on automated accounts are a first step. Radical redesign of networks and of trending indicators so that flooding attacks are less effective may be a second.

The second requires general standards for voting at the federal level, and a constitutional guarantee of the right to vote. Technical experts nearly universally favor robust voting systems that would combine paper records with random post-election auditing, to prevent fraud and secure public confidence in voting. Other steps to ensure proper ballot design, and standardize vote counting and reporting will take more time and discussion — yet the record of other countries show that they are not impossible.

The US is nearly unique among major democracies in the persistent flaws of its election machinery. Yet voting is not the only important form of democratic information. Apparent efforts to deliberately skew the US census against counting undocumented immigrants show the need for a more general audit of the political information systems that we need if democracy is to function properly.

It’s easier to respond to Russian hackers through sanctions, counter-attacks and the like than to domestic political attacks that undermine US democracy. To preserve the basic political freedoms of democracy requires recognizing that these freedoms are sometimes going to be abused by politicians such as Donald Trump. The best that we can do is to minimize the possibilities of abuse up to the point where they encroach on basic freedoms and harden the general institutions that secure democratic information against attacks intended to undermine them.

This essay was co-authored with Henry Farrell, and previously appeared on Motherboard, with a terrible headline that I was unable to get changed.

Using Machine Learning to Create Fake Fingerprints

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/11/using_machine_l.html

Researchers are able to create fake fingerprints that result in a 20% false-positive rate.

The problem is that these sensors obtain only partial images of users’ fingerprints — at the points where they make contact with the scanner. The paper noted that since partial prints are not as distinctive as complete prints, the chances of one partial print getting matched with another is high.

The artificially generated prints, dubbed DeepMasterPrints by the researchers, capitalize on the aforementioned vulnerability to accurately imitate one in five fingerprints in a database. The database was originally supposed to have only an error rate of one in a thousand.

Another vulnerability exploited by the researchers was the high prevalence of some natural fingerprint features such as loops and whorls, compared to others. With this understanding, the team generated some prints that contain several of these common features. They found that these artificial prints were more likely to match with other prints than would be normally possible.

If this result is robust — and I assume it will be improved upon over the coming years — it will make the current generation of fingerprint readers obsolete as secure biometrics. It also opens a new chapter in the arms race between biometric authentication systems and fake biometrics that can fool them.

More interestingly, I wonder if similar techniques can be brought to bear against other biometrics are well.

Research paper.

Slashdot thread

Information Attacks against Democracies

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/11/information_att.html

Democracy is an information system.

That’s the starting place of our new paper: “Common-Knowledge Attacks on Democracy.” In it, we look at democracy through the lens of information security, trying to understand the current waves of Internet disinformation attacks. Specifically, we wanted to explain why the same disinformation campaigns that act as a stabilizing influence in Russia are destabilizing in the United States.

The answer revolves around the different ways autocracies and democracies work as information systems. We start by differentiating between two types of knowledge that societies use in their political systems. The first is common political knowledge, which is the body of information that people in a society broadly agree on. People agree on who the rulers are and what their claim to legitimacy is. People agree broadly on how their government works, even if they don’t like it. In a democracy, people agree about how elections work: how districts are created and defined, how candidates are chosen, and that their votes count­ — even if only roughly and imperfectly.

We contrast this with a very different form of knowledge that we call contested political knowledge, which is, broadly, things that people in society disagree about. Examples are easy to bring to mind: how much of a role the government should play in the economy, what the tax rules should be, what sorts of regulations are beneficial and what sorts are harmful, and so on.

This seems basic, but it gets interesting when we contrast both of these forms of knowledge across autocracies and democracies. These two forms of government have incompatible needs for common and contested political knowledge.

For example, democracies draw upon the disagreements within their population to solve problems. Different political groups have different ideas of how to govern, and those groups vie for political influence by persuading voters. There is also long-term uncertainty about who will be in charge and able to set policy goals. Ideally, this is the mechanism through which a polity can harness the diversity of perspectives of its members to better solve complex policy problems. When no-one knows who is going to be in charge after the next election, different parties and candidates will vie to persuade voters of the benefits of different policy proposals.

But in order for this to work, there needs to be common knowledge both of how government functions and how political leaders are chosen. There also needs to be common knowledge of who the political actors are, what they and their parties stand for, and how they clash with each other. Furthermore, this knowledge is decentralized across a wide variety of actors­ — an essential element, since ordinary citizens play a significant role in political decision making.

Contrast this with an autocracy. There, common political knowledge about who is in charge over the long term and what their policy goals are is a basic condition of stability. Autocracies do not require common political knowledge about the efficacy and fairness of elections, and strive to maintain a monopoly on other forms of common political knowledge. They actively suppress common political knowledge about potential groupings within their society, their levels of popular support, and how they might form coalitions with each other. On the other hand, they benefit from contested political knowledge about nongovernmental groups and actors in society. If no one really knows which other political parties might form, what they might stand for, and what support they might get, that itself is a significant barrier to those parties ever forming.

This difference has important consequences for security. Authoritarian regimes are vulnerable to information attacks that challenge their monopoly on common political knowledge. They are vulnerable to outside information that demonstrates that the government is manipulating common political knowledge to their own benefit. And they are vulnerable to attacks that turn contested political knowledge­ — uncertainty about potential adversaries of the ruling regime, their popular levels of support and their ability to form coalitions­ — into common political knowledge. As such, they are vulnerable to tools that allow people to communicate and organize more easily, as well as tools that provide citizens with outside information and perspectives.

For example, before the first stirrings of the Arab Spring, the Tunisian government had extensive control over common knowledge. It required everyone to publicly support the regime, making it hard for citizens to know how many other people hated it, and it prevented potential anti-regime coalitions from organizing. However, it didn’t pay attention in time to Facebook, which allowed citizens to talk more easily about how much they detested their rulers, and, when an initial incident sparked a protest, to rapidly organize mass demonstrations against the regime. The Arab Spring faltered in many countries, but it is no surprise that countries like Russia see the Internet openness agenda as a knife at their throats.

Democracies, in contrast, are vulnerable to information attacks that turn common political knowledge into contested political knowledge. If people disagree on the results of an election, or whether a census process is accurate, then democracy suffers. Similarly, if people lose any sense of what the other perspectives in society are, who is real and who is not real, then the debate and argument that democracy thrives on will be degraded. This is what seems to be Russia’s aims in their information campaigns against the US: to weaken our collective trust in the institutions and systems that hold our country together. This is also the situation that writers like Adrien Chen and Peter Pomerantsev describe in today’s Russia, where no one knows which parties or voices are genuine, and which are puppets of the regime, creating general paranoia and despair.

This difference explains how the same policy measure can increase the stability of one form of regime and decrease the stability of the other. We have already seen that open information flows have benefited democracies while at the same time threatening autocracies. In our language, they transform regime-supporting contested political knowledge into regime-undermining common political knowledge. And much more recently, we have seen other uses of the same information flows undermining democracies by turning regime-supported common political knowledge into regime-undermining contested political knowledge.

In other words, the same fake news techniques that benefit autocracies by making everyone unsure about political alternatives undermine democracies by making people question the common political systems that bind their society.

This framework not only helps us understand how different political systems are vulnerable and how they can be attacked, but also how to bolster security in democracies. First, we need to better defend the common political knowledge that democracies need to function. That is, we need to bolster public confidence in the institutions and systems that maintain a democracy. Second, we need to make it harder for outside political groups to cooperate with inside political groups and organize disinformation attacks, through measures like transparency in political funding and spending. And finally, we need to treat attacks on common political knowledge by insiders as being just as threatening as the same attacks by foreigners.

There’s a lot more in the paper.

This essay was co-authored by Henry Farrell, and previously appeared on Lawfare.com.

Privacy and Security of Data at Universities

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/11/privacy_and_sec.html

Interesting paper: “Open Data, Grey Data, and Stewardship: Universities at the Privacy Frontier,” by Christine Borgman:

Abstract: As universities recognize the inherent value in the data they collect and hold, they encounter unforeseen challenges in stewarding those data in ways that balance accountability, transparency, and protection of privacy, academic freedom, and intellectual property. Two parallel developments in academic data collection are converging: (1) open access requirements, whereby researchers must provide access to their data as a condition of obtaining grant funding or publishing results in journals; and (2) the vast accumulation of “grey data” about individuals in their daily activities of research, teaching, learning, services, and administration. The boundaries between research and grey data are blurring, making it more difficult to assess the risks and responsibilities associated with any data collection. Many sets of data, both research and grey, fall outside privacy regulations such as HIPAA, FERPA, and PII. Universities are exploiting these data for research, learning analytics, faculty evaluation, strategic decisions, and other sensitive matters. Commercial entities are besieging universities with requests for access to data or for partnerships to mine them. The privacy frontier facing research universities spans open access practices, uses and misuses of data, public records requests, cyber risk, and curating data for privacy protection. This Article explores the competing values inherent in data stewardship and makes recommendations for practice by drawing on the pioneering work of the University of California in privacy and information security, data governance, and cyber risk.

Security of Solid-State-Drive Encryption

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/11/security_of_sol.html

Interesting research: “Self-encrypting deception: weaknesses in the encryption of solid state drives (SSDs)“:

Abstract: We have analyzed the hardware full-disk encryption of several SSDs by reverse engineering their firmware. In theory, the security guarantees offered by hardware encryption are similar to or better than software implementations. In reality, we found that many hardware implementations have critical security weaknesses, for many models allowing for complete recovery of the data without knowledge of any secret. BitLocker, the encryption software built into Microsoft Windows will rely exclusively on hardware full-disk encryption if the SSD advertises supported for it. Thus, for these drives, data protected by BitLocker is also compromised. This challenges the view that hardware encryption is preferable over software encryption. We conclude that one should not rely solely on hardware encryption offered by SSDs.

EDITED TO ADD: The NSA is known to attack firmware of SSDs.

EDITED TO ADD (11/13): CERT advisory. And older research.

Detecting Deep Fakes

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/10/detecting_deep_.html

This story nicely illustrates the arms race between technologies to create fake videos and technologies to detect fake videos:

These fakes, while convincing if you watch a few seconds on a phone screen, aren’t perfect (yet). They contain tells, like creepily ever-open eyes, from flaws in their creation process. In looking into DeepFake’s guts, Lyu realized that the images that the program learned from didn’t include many with closed eyes (after all, you wouldn’t keep a selfie where you were blinking, would you?). “This becomes a bias,” he says. The neural network doesn’t get blinking. Programs also might miss other “physiological signals intrinsic to human beings,” says Lyu’s paper on the phenomenon, such as breathing at a normal rate, or having a pulse. (Autonomic signs of constant existential distress are not listed.) While this research focused specifically on videos created with this particular software, it is a truth universally acknowledged that even a large set of snapshots might not adequately capture the physical human experience, and so any software trained on those images may be found lacking.

Lyu’s blinking revelation revealed a lot of fakes. But a few weeks after his team put a draft of their paper online, they got anonymous emails with links to deeply faked YouTube videos whose stars opened and closed their eyes more normally. The fake content creators had evolved.

I don’t know who will win this arms race, if there ever will be a winner. But the problem with fake videos goes deeper: they affect people even if they are later told that they are fake, and there always will be people that will believe they are real, despite any evidence to the contrary.

China’s Hacking of the Border Gateway Protocol

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/10/chinas_hacking_.html

This is a long — and somewhat technical — paper by Chris C. Demchak and Yuval Shavitt about China’s repeated hacking of the Internet Border Gateway Protocol (BGP): “China’s Maxim ­ Leave No Access Point Unexploited: The Hidden Story of China Telecom’s BGP Hijacking.”

BGP hacking is how large intelligence agencies manipulate Internet routing to make certain traffic easier to intercept. The NSA calls it “network shaping” or “traffic shaping.” Here’s a document from the Snowden archives outlining how the technique works with Yemen.

EDITED TO ADD (10/27): BoingBoing post.

How DNA Databases Violate Everyone’s Privacy

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/10/how_dna_databas.html

If you’re an American of European descent, there’s a 60% chance you can be uniquely identified by public information in DNA databases. This is not information that you have made public; this is information your relatives have made public.

Research paper:

“Identity inference of genomic data using long-range familial searches.”

Abstract: Consumer genomics databases have reached the scale of millions of individuals. Recently, law enforcement authorities have exploited some of these databases to identify suspects via distant familial relatives. Using genomic data of 1.28 million individuals tested with consumer genomics, we investigated the power of this technique. We project that about 60% of the searches for individuals of European-descent will result in a third cousin or closer match, which can allow their identification using demographic identifiers. Moreover, the technique could implicate nearly any US-individual of European-descent in the near future. We demonstrate that the technique can also identify research participants of a public sequencing project. Based on these results, we propose a potential mitigation strategy and policy implications to human subject research.

A good news article.

Detecting Credit Card Skimmers

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/10/detecting_credi.html

Interesting research paper: “Fear the Reaper: Characterization and Fast Detection of Card Skimmers“:

Abstract: Payment card fraud results in billions of dollars in losses annually. Adversaries increasingly acquire card data using skimmers, which are attached to legitimate payment devices including point of sale terminals, gas pumps, and ATMs. Detecting such devices can be difficult, and while many experts offer advice in doing so, there exists no large-scale characterization of skimmer technology to support such defenses. In this paper, we perform the first such study based on skimmers recovered by the NYPD’s Financial Crimes Task Force over a 16 month period. After systematizing these devices, we develop the Skim Reaper, a detector which takes advantage of the physical properties and constraints necessary for many skimmers to steal card data. Our analysis shows the Skim Reaper effectively detects 100% of devices supplied by the NYPD. In so doing, we provide the first robust and portable mechanism for detecting card skimmers.

Boing Boing post.

Facebook Is Using Your Two-Factor Authentication Phone Number to Target Advertising

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/10/facebook_is_usi.html

From Kashmir Hill:

Facebook is not content to use the contact information you willingly put into your Facebook profile for advertising. It is also using contact information you handed over for security purposes and contact information you didn’t hand over at all, but that was collected from other people’s contact books, a hidden layer of details Facebook has about you that I’ve come to call “shadow contact information.” I managed to place an ad in front of Alan Mislove by targeting his shadow profile. This means that the junk email address that you hand over for discounts or for shady online shopping is likely associated with your account and being used to target you with ads.

Here’s the research paper. Hill again:

They found that when a user gives Facebook a phone number for two-factor authentication or in order to receive alerts about new log-ins to a user’s account, that phone number became targetable by an advertiser within a couple of weeks. So users who want their accounts to be more secure are forced to make a privacy trade-off and allow advertisers to more easily find them on the social network.

Evidence for the Security of PKCS #1 Digital Signatures

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/09/evidence_for_th.html

This is interesting research: “On the Security of the PKCS#1 v1.5 Signature Scheme“:

Abstract: The RSA PKCS#1 v1.5 signature algorithm is the most widely used digital signature scheme in practice. Its two main strengths are its extreme simplicity, which makes it very easy to implement, and that verification of signatures is significantly faster than for DSA or ECDSA. Despite the huge practical importance of RSA PKCS#1 v1.5 signatures, providing formal evidence for their security based on plausible cryptographic hardness assumptions has turned out to be very difficult. Therefore the most recent version of PKCS#1 (RFC 8017) even recommends a replacement the more complex and less efficient scheme RSA-PSS, as it is provably secure and therefore considered more robust. The main obstacle is that RSA PKCS#1 v1.5 signatures use a deterministic padding scheme, which makes standard proof techniques not applicable.

We introduce a new technique that enables the first security proof for RSA-PKCS#1 v1.5 signatures. We prove full existential unforgeability against adaptive chosen-message attacks (EUF-CMA) under the standard RSA assumption. Furthermore, we give a tight proof under the Phi-Hiding assumption. These proofs are in the random oracle model and the parameters deviate slightly from the standard use, because we require a larger output length of the hash function. However, we also show how RSA-PKCS#1 v1.5 signatures can be instantiated in practice such that our security proofs apply.

In order to draw a more complete picture of the precise security of RSA PKCS#1 v1.5 signatures, we also give security proofs in the standard model, but with respect to weaker attacker models (key-only attacks) and based on known complexity assumptions. The main conclusion of our work is that from a provable security perspective RSA PKCS#1 v1.5 can be safely used, if the output length of the hash function is chosen appropriately.

I don’t think the protocol is “provably secure,” meaning that it cannot have any vulnerabilities. What this paper demonstrates is that there are no vulnerabilities under the model of the proof. And, more importantly, that PKCS #1 v1.5 is as secure as any of its successors like RSA-PSS and RSA Full-Domain.

New Findings About Prime Number Distribution Almost Certainly Irrelevant to Cryptography

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/09/new_findings_ab.html

Lots of people are e-mailing me about this new result on the distribution of prime numbers. While interesting, it has nothing to do with cryptography. Cryptographers aren’t interested in how to find prime numbers, or even in the distribution of prime numbers. Public-key cryptography algorithms like RSA get their security from the difficulty of factoring large composite numbers that are the product of two prime numbers. That’s completely different.

John Mueller and Mark Stewart on the Risks of Terrorism

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/08/john_mueller_an.html

Another excellent paper by the Mueller/Stewart team: “Terrorism and Bathtubs: Comparing and Assessing the Risks“:

Abstract: The likelihood that anyone outside a war zone will be killed by an Islamist extremist terrorist is extremely small. In the United States, for example, some six people have perished each year since 9/11 at the hands of such terrorists — vastly smaller than the number of people who die in bathtub drownings. Some argue, however, that the incidence of terrorist destruction is low because counterterrorism measures are so effective. They also contend that terrorism may well become more frequent and destructive in the future as terrorists plot and plan and learn from experience, and that terrorism, unlike bathtubs, provides no benefit and exacts costs far beyond those in the event itself by damagingly sowing fear and anxiety and by requiring policy makers to adopt countermeasures that are costly and excessive. This paper finds these arguments to be wanting. In the process, it concludes that terrorism is rare outside war zones because, to a substantial degree, terrorists don’t exist there. In general, as with rare diseases that kill few, it makes more policy sense to expend limited funds on hazards that inflict far more damage. It also discusses the issue of risk communication for this hazard.

New Ways to Track Internet Browsing

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/08/new_ways_to_tra.html

Interesting research on web tracking: “Who Left Open the Cookie Jar? A Comprehensive Evaluation of Third-Party Cookie Policies:

Abstract: Nowadays, cookies are the most prominent mechanism to identify and authenticate users on the Internet. Although protected by the Same Origin Policy, popular browsers include cookies in all requests, even when these are cross-site. Unfortunately, these third-party cookies enable both cross-site attacks and third-party tracking. As a response to these nefarious consequences, various countermeasures have been developed in the form of browser extensions or even protection mechanisms that are built directly into the browser.

In this paper, we evaluate the effectiveness of these defense mechanisms by leveraging a framework that automatically evaluates the enforcement of the policies imposed to third-party requests. By applying our framework, which generates a comprehensive set of test cases covering various web mechanisms, we identify several flaws in the policy implementations of the 7 browsers and 46 browser extensions that were evaluated. We find that even built-in protection mechanisms can be circumvented by multiple novel techniques we discover. Based on these results, we argue that our proposed framework is a much-needed tool to detect bypasses and evaluate solutions to the exposed leaks. Finally, we analyze the origin of the identified bypass techniques, and find that these are due to a variety of implementation, configuration and design flaws.

The researchers discovered many new tracking techniques that work despite all existing anonymous browsing tools. These have not yet been seen in the wild, but that will change soon.

Three news articles. BoingBoing post.

Measuring the Rationality of Security Decisions

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/08/measuring_the_r.html

Interesting research: “Dancing Pigs or Externalities? Measuring the Rationality of
Security Decisions
“:

Abstract: Accurately modeling human decision-making in security is critical to thinking about when, why, and how to recommend that users adopt certain secure behaviors. In this work, we conduct behavioral economics experiments to model the rationality of end-user security decision-making in a realistic online experimental system simulating a bank account. We ask participants to make a financially impactful security choice, in the face of transparent risks of account compromise and benefits offered by an optional security behavior (two-factor authentication). We measure the cost and utility of adopting the security behavior via measurements of time spent executing the behavior and estimates of the participant’s wage. We find that more than 50% of our participants made rational (e.g., utility optimal) decisions, and we find that participants are more likely to behave rationally in the face of higher risk. Additionally, we find that users’ decisions can be modeled well as a function of past behavior (anchoring effects), knowledge of costs, and to a lesser extent, users’ awareness of risks and context (R2=0.61). We also find evidence of endowment effects, as seen in other areas of economic and psychological decision-science literature, in our digital-security setting. Finally, using our data, we show theoretically that a “one-size-fits-all” emphasis on security can lead to market losses, but that adoption by a subset of users with higher risks or lower costs can lead to market gains