Security Engineering: Computers versus Bridges

Joseph Lorenzo Hall has a post at the Center for Democracy and Technology, “Taking the Pulse of Security Research.” One part of the post is an expert statement on security research, and I’m one of the experts who has signed on.

I fully support what CDT chose to include in the statement, and I want to go deeper. The back and forth of design and critique is not only a critical part of how an individual design gets better, but fields in which such criticism is the norm advance faster.

A quick search in Petroski’s Engineers of Dreams: Great Bridge Builders and the Spanning of America brings us the following. (The Roeblings built the Brooklyn Bridge, Lindenthal had proposed a concept for the crossing, which lost to Roebling’s, and he built many others.)

In Lindenthal’s case, he was so committed to the suspension concept for bridging the Hudson River that he turned the argument naturally and not unfairly to his use. Lindenthal admitted, for example, that it was “a popular assumption that suspension bridges cannot be well used for railroad purposes,” and further conceded that throughout the world there was only one suspension bridge then carrying railroad tracks, Roebling’s Niagara Gorge Bridge, completed in 1854, over which trains had to move slowly. However, rather than seeing this as scant evidence for his case, Lindenthal held up as a model the “greater moral courage and more abiding faith in the truth of constructive principles” that Roebling needed to build his bridge in the face of contemporary criticism by the “most eminent bridge engineers then living.” In Lindenthal’s time, three decades later, it was not merely a question of moral courage; “nowadays bridges are not built on faith,” and there was “not another field of applied mechanics where results can be predicted with so much precision as in bridges of iron and steel.” (“Engineers of Dreams: Great Bridge Builders and the Spanning of America,” Henry Petroski)

Importantly for the case which CDT is making, over the span of thirty years, we went from a single suspension bridge to “much precision” in their construction. That progress happened because criticisms and questions are standard while a bridge is proposed, and if it fails, there are inquests and inquiries as to why.

In his The Great Bridge: The Epic Story of the Building of the Brooklyn Bridge, David McCullough describes the prolonged public discussion of the engineering merits:

It had been said repeatedly by critics of the plan that a single span of such length was impossible, that the bridge trains would shake the structure to pieces and, more frequently, that no amount of calculations on paper could guarantee how it might hold up in heavy winds, but the odds were that the great river span would thrash and twist until it snapped in two and fell, the way the Wheeling Bridge had done (a spectacle some of his critics hoped to be on hand for, to judge by the tone of their attacks).

The process of debating plans for a bridge strengthen, not weaken, the resulting structure. Both books are worth reading as you think about how to advance the field of cybersecurity.

Image credit: Cleveland Electric, on their page about a fiber optic structural monitoring system which they retro-fitted onto the bridge in question.

John Harrison’s Struggle Continues

Today is John Harrison’s 352nd birthday, and Google has a doodle to celebrate. Harrison was rescued from historical obscurity by Dava Sobel’s excellent book Longitude, which documented Harrison’s struggle to first build and then demonstrate the superiority of his clocks to the mathematical and astronomical solutions heralded by leading scientists of the day. Their methods were complex, tedious and hard to execute from the deck of a ship.

To celebrate, I’d like to share this photo I took at the Royal Museums Greenwich in 2017:

Harrison Worksheet framed

(A Full size version is on Flickr.)

As the placard says, “First produced in 1768, this worksheet gave navigators an easy process for calculating their longitude using new instruments and the Nautical Almanac. Each naval ship’s master was required to train with qualified teachers in London or Portsmouth in order to gain a certificate of navigational competence.” (Emphasis added.)

Keep the Bombe on the Bletchley Park Estate

There’s a fundraising campaign to “Keep the Bombe on the Bletchley Park Estate.”

The Bombe was a massive intellectual and engineering achievement at the British codebreaking center at Bletchley Park during the second world war. The Bombes were all disassembled after the war, and the plans destroyed, making the reconstruction of the Bombe at Bletchley a second impressive achievement.

My photo is from the exhibit on the reconstruction.

Babylonian Triginometry

a fresh look at a 3700-year-old clay tablet suggests that Babylonian mathematicians not only developed the first trig table, beating the Greeks to the punch by more than 1000 years, but that they also figured out an entirely new way to look at the subject. However, other experts on the clay tablet, known as Plimpton 322 (P322), say the new work is speculative at best. (“This ancient Babylonian tablet may contain the first evidence of trigonometry.”)

The paper, “Plimpton 322 is Babylonian exact sexagesimal trigonometry” is short and open access, and also contains this gem:

If this interpretation is correct, then P322 replaces Hipparchus’ ‘table of chords’ as the world’s oldest trigonometric table — but it is additionally unique because of its exact nature, which would make it the world’s only completely accurate trigonometric table. These insights expose an entirely new level of sophistication for OB mathematics.

The Unanimous Declaration of The 13 United States


In CONGRESS, July 4, 1776

The unanimous Declaration of the thirteen united States of America,

When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. –That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, –That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security. —Such has been the patient sufferance of these Colonies; and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present King of Great Britain [George III] is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world.

He has refused his Assent to Laws, the most wholesome and necessary for the public good.

He has forbidden his Governors to pass Laws of immediate and pressing importance, unless suspended in their operation till his Assent should be obtained; and when so suspended, he has utterly neglected to attend to them.

He has refused to pass other Laws for the accommodation of large districts of people, unless those people would relinquish the right of Representation in the Legislature, a right inestimable to them and formidable to tyrants only.

He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public Records, for the sole purpose of fatiguing them into compliance with his measures.

He has dissolved Representative Houses repeatedly, for opposing with manly firmness his invasions on the rights of the people.

He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed to all the dangers of invasion from without, and convulsions within.

He has endeavoured to prevent the population of these States; for that purpose obstructing the Laws for Naturalization of Foreigners; refusing to pass others to encourage their migrations hither, and raising the conditions of new Appropriations of Lands.

He has obstructed the Administration of Justice, by refusing his Assent to Laws for establishing Judiciary powers.

He has made Judges dependent on his Will alone, for the tenure of their offices, and the amount and payment of their salaries.

He has erected a multitude of New Offices, and sent hither swarms of Officers to harass our people, and eat out their substance.

He has kept among us, in times of peace, Standing Armies without the consent of our legislatures.

He has affected to render the Military independent of and superior to the Civil power.

He has combined with others to subject us to a jurisdiction foreign to our constitution and unacknowledged by our laws; giving his Assent to their Acts of pretended Legislation:

For Quartering large bodies of armed troops among us:

For protecting them, by a mock Trial, from punishment for any Murders which they should commit on the Inhabitants of these States:

For cutting off our Trade with all parts of the world:

For imposing Taxes on us without our Consent:

For depriving us, in many cases, of the benefits of Trial by Jury:

For transporting us beyond Seas to be tried for pretended offences:

For abolishing the free System of English Laws in a neighbouring Province, establishing therein an Arbitrary government, and enlarging its Boundaries so as to render it at once an example and fit instrument for introducing the same absolute rule into these Colonies:

For taking away our Charters, abolishing our most valuable Laws, and altering fundamentally the Forms of our Governments:

For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.

He has abdicated Government here, by declaring us out of his Protection and waging War against us.

He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the lives of our people.

He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and tyranny, already begun with circumstances of Cruelty and perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the Head of a civilized nation.

He has constrained our fellow Citizens taken Captive on the high Seas to bear Arms against their Country, to become the executioners of their friends and Brethren, or to fall themselves by their Hands.

He has excited domestic insurrections amongst us, and has endeavoured to bring on the inhabitants of our frontiers, the merciless Indian Savages, whose known rule of warfare, is an undistinguished destruction of all ages, sexes and conditions.

In every stage of these Oppressions We have Petitioned for Redress in the most humble terms: Our repeated Petitions have been answered only by repeated injury. A Prince whose character is thus marked by every act which may define a Tyrant, is unfit to be the ruler of a free people.

Nor have We been wanting in attentions to our British brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends.

We, therefore, the Representatives of the united States of America, in General Congress, Assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the Name, and by the Authority of the good People of these Colonies, solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between them and the State of Great Britain, is and ought to be totally dissolved; and that as Free and Independent States, they have full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which Independent States may of right do. And for the support of this Declaration, with a firm reliance on the protection of divine Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor.

The signers of the Declaration represented the new states as follows:

New Hampshire

Josiah Bartlett, William Whipple, Matthew Thornton


John Hancock, Samual Adams, John Adams, Robert Treat Paine, Elbridge Gerry

Rhode Island

Stephen Hopkins, William Ellery


Roger Sherman, Samuel Huntington, William Williams, Oliver Wolcott

New York

William Floyd, Philip Livingston, Francis Lewis, Lewis Morris

New Jersey

Richard Stockton, John Witherspoon, Francis Hopkinson, John Hart, Abraham Clark


Robert Morris, Benjamin Rush, Benjamin Franklin, John Morton, George Clymer, James Smith, George Taylor, James Wilson, George Ross


Caesar Rodney, George Read, Thomas McKean


Samuel Chase, William Paca, Thomas Stone, Charles Carroll of Carrollton


George Wythe, Richard Henry Lee, Thomas Jefferson, Benjamin Harrison, Thomas Nelson, Jr., Francis Lightfoot Lee, Carter Braxton

North Carolina

William Hooper, Joseph Hewes, John Penn

South Carolina

Edward Rutledge, Thomas Heyward, Jr., Thomas Lynch, Jr., Arthur Middleton


Button Gwinnett, Lyman Hall, George Walton

Image: Washington’s copy of the Declaration of Independence, from the Library of Congress.

Calls for an NTSB?

In September, Steve Bellovin and I asked “Why Don’t We Have an Incident Repository?.”

I’m continuing to do research on the topic, and I’m interested in putting together a list of such things. I’d like to ask you for two favors.

First, if you remember such things, can you tell me about it? I recall “Computers at Risk,” the National Cyber Leap Year report, and the Bellovin & Neumann editorial in IEEE S&P. Oh, and “The New School of Information Security.” But I’m sure there have been others.

In particular, what I’m looking for are calls like this one in Computers at Risk (National Academies Press, 1991):

3a. Build a repository of incident data. The committee recommends that a repository of incident information be established for use in research, to increase public awareness of successful penetrations and existing vulnerabilities, and to assist security practitioners, who often have difficulty persuading managers to invest in security. This database should categorize, report, and track pertinent instances of system security-related threats, risks, and failures. […] One possible model for data collection is the incident reporting system administered by the National Transportation Safety Board… (chapter 3)

Second, I am trying to do searches such as “cites “Computers at Risk” and contains ‘NTSB’.” I have tried without luck to do this on Google Scholar, Microsoft Academic and Semantic Scholar. Only Google seems to be reliably identifying that report. Is there a good way to perform such a search?

The Web We Have to Save

Hossein Derakhshan was recently released from jail in Iran. He’s written a long and thoughtful article “The Web We Have to Save.” It’s worth reading in full, but here’s an excerpt:

Some of it is visual. Yes, it is true that all my posts on Twitter and Facebook look something similar to a personal blog: They are collected in reverse-chronological order, on a specific webpage, with direct web addresses to each post. But I have very little control over how it looks like; I can’t personalize it much. My page must follow a uniform look which the designers of the social network decide for me.

The centralization of information also worries me because it makes it easier for things to disappear. After my arrest, my hosting service closed my account, because I wasn’t able to pay its monthly fee. But at least I had a backup of all my posts in a database on my own web server. (Most blogging platforms used to enable you to transfer your posts and archives to your own web space, whereas now most platforms don’t let you so.) Even if I didn’t, the Internet archive might keep a copy. But what if my account on Facebook or Twitter is shut down for any reason? Those services themselves may not die any time soon, but it would be not too difficult to imagine a day many American services shut down accounts of anyone who is from Iran, as a result of the current regime of sanctions. If that happened, I might be able to download my posts in some of them, and let’s assume the backup can be easily imported into another platform. But what about the unique web address for my social network profile? Would I be able to claim it back later, after somebody else has possessed it? Domain names switch hands, too, but managing the process is easier and more clear— especially since there is a financial relationship between you and the seller which makes it less prone to sudden and untransparent decisions.

But the scariest outcome of the centralization of information in the age of social networks is something else: It is making us all much less powerful in relation to governments and corporations.

Ironically, I tweeted a link, but I think I’m going to try to go back to more blogging, even if the content might fit somewhere else. Hossein’s right. There’s a web here, and we should work to save it.

(Previous mentions of Hossein: Hoder’s Denial“, “Free Hossein Derakhshan.”)

Chaos and Legitimacy

At BruCon 0x06, I was awoken from a nap to the sound of canons, and looked out my window to see soldiers marching through the streets. It turns out they were celebrating the 200th anniversary of the Treaty of Ghent. As I’m sure you’ll recall from history class Wikipedia, the Treaty of Ghent ended the war of 1812, and was the second war between Great Britain and the less Canadian parts of its North American colonies.

Treaty of Ghent Anniversary Celebration

Lately, I’ve been thinking a lot about that and what it tells us about Iraq, ISIS and more recently, Ferguson, and I want to write some of it down to see if it makes sense.

Much of our policy in Iraq and Afghanistan seems to operate on a model of history which goes something like this: after the revolutionary war, town meetings coalesced into the Constitution, and we all lived democratically ever after. It’s an ahistorical view that forgets the Articles of Confederation, the Whiskey Rebellion, Shays Rebellion, and what some in the American south still call “the War of Northern Aggression.” It takes time to develop the institutions of a functioning democratic society.

Is it any surprise that after years of dictatorships, torture of dissidents, children growing up under sanctions (in the case of Iraq), occupation, and civil war, the people of Iraq are not using democracy to solve their problems? That they fight over how to run their country?

While each has a unique history and set of circumstances, it appears to me that there is, across Afghanistan, Iraq, Syria, a crisis of legitimacy. The people who live in those areas have disagreements about not only who should lead them, or what policies should be in place, but about the process for selecting their leaders or governments, and the powers those governments should have.

Their disagreements are strong enough that many people are willing to take up arms rather than acquiesce to other visions. Our understanding of these disagreements is muddied by use of terms like “militia”, “the legitimate security forces” or “the so-called Islamic State.”

The Islamic State, with territory, an army, and a currency, is in many ways, no more or no less legitimate than the army and currency of Prince Assad of Syria. (He is a prince in all but name, having inherited power from his father, that literal inheritance of power being the defining feature of princes.) Assad has taken the step of staging a Potemkin village election, because he understands that legitimacy (rather than power) comes from the consent and agreement of the governed.

This is why Churchill said that democracy is the worst form of government, save all those others that have been tried. No one really thinks that asking a bunch of people who can’t be bothered to vote who should lead them is a great way to get the best people into government. But democracy is a unique way to give people a voice, and in that voice, get their consent. The form democracy, that everyone has a voice, is what gives it its legitimacy. Another way to say that is it’s the ballot or the bullet. (If you haven’t listened to Malcom X give that speech, it’s really an outstanding use of your time. Ballot or Bullet Part I, Ballot or Bullet Part II. In two parts from 100 American Speeches, not sure why it’s two-parted.)

Developing legitimacy requires both institutions and time. The institutions must show that they are reliably better than other choices, or people will pursue those other choices. When Federal grand juries return indictments in 162,000 out of 162,011 cases brought to them, it is reasonable to question if they are a worthwhile or trustworthy institution, or act simply as an instrument of power. From that same 538 Story, grand juries in Dallas reviewed 81 shootings by officers, and returns a single indictment. It is easy to think something is out of whack.

What I think I see in Ferguson is that the institutions of justice have failed, again and again. They didn’t just fail when Darren Wilson shot Michael Brown. Police officers can and will make bad decisions. But afterwards, they continued to fail. The medical examiner didn’t take photos because the battery in his camera died. The prosecutor led Darren Wilson’s testimony.
The institutions didn’t just failed in the moment, they couldn’t be made to work under an intense spotlight. The figures about grand jury indictments indicate that they system is failing victims of police violence. (Although Law Proffesor Paul Cassell makes a case that the grand jury did the right thing, and Wilson had a strong self-defense claim.) However, the institutions didn’t fail completely. A grand jury met, its activity was transcribed and the transcript was released. These elements of transparency allow us to judge the system, and find it wanting. But even while wanting, it’s better than judgement in the ‘court of public opinion,’ and its better than mob justice or lynchings.

These failures may lead reasonable people to ask what alternatives to violence exist? It may lead people to think that violence or destruction is their best option. Perhaps the democratic bargain as a whole is no longer sufficiently legitimate to the people protesting or even rioting in Ferguson. To be clear, I don’t think that the violence or property destruction will improve their lives. In fact I believe that violence and property destruction will make their lives worse. I also think that the people rioting, if they would sit down and talk it through might even agree that burning their own community won’t help. But they’re living in a system where things are more arrest warrants than people.

The chaos in Ferguson, like the chaos in Boston in 1776, like the chaos in Iraq, like the chaos in Syria, may be stopped, for a time, by more violence. But violence will not correct the underlying issues of legitimacy.

(There’s a whole related history of the use of offices to enrich office-holders, including the sale of military commissions, the sale of tax collection jobs, etc. I think that’s too complex for me to work into a single blog post. But briefly, the idea that positions were held as a public trust was an important development. We’ve lost it to the idea that because
officials will sometimes act in their own interest, we should only expect them to act that way. In no longer holding people to an ideal, we’re losing something.)

3D-printed guns and the crypto wars

So there’s a working set of plans for the “Liberator.” It’s a working firearm you can print on a 3d printer. You can no longer get the files from the authors, whose site states: “DEFCAD files are being removed from public access at the request of the US Department of Defense Trade Controls.
Until further notice, the United States government claims control of the information.” Cue Streisand Effect.

My understanding is that the censorship order was issued under the ITARs, the “International Traffic in Arms Regulations.” Cory Doctorow has said “Impact litigation — where good precedents overturn bad rules — is greatly assisted by good facts and good defendants. I would much rather the Internet-as-library question be ruled on in a less emotionally overheated realm than DIY guns.” I think that’s reasonable, but recall that Shaw claimed that all progress depends on the unreasonable man.

Doctorow also refers to Bernstein, who did good work, but his lawsuit was the last nail in ITARs applying to crypto, not the first. (ITARs still do apply to crypto, but in ways that allow both open source and commercial software to ship strong crypto, which wasn’t the case in the 90s.) Me, I see lots of evidence that gun control doesn’t work any better than alcohol control or marijuana control. And I think that the regulatory response by the DoD is silly. (One can argue that the law gives them no choice, but I don’t believe that to be the case.)

So the right step was demonstrated for crypto nearly 20 years ago by Phil Karn. He filed a pair of “Commodity Jurisdiction Requests.” One for Applied Cryptography, a book, and one for a floppy disk containing the source code.

The State Department ruled that even though the book itself is “in the public domain” and hence outside their jurisdiction, a floppy disk containing the exact same source code as printed in the book is a “munition” requiring a license to export. It’s old news that the US Government believes only Americans (and maybe a few Canadians) can write C code, but now they have apparently decided that foreigners can’t type either!

In the past three years I have taken my case to all three branches of the federal government. Here is the full case history in the Executive and Judicial branches, including all my correspondence with the US State Department, the Bureau of Export Administration (BXA) in the Commerce Department, the US District Court for the District of Columbia, and the Court of Appeals for the DC Circuit.

I believe the analogy is obvious. The DefCad files are 2mb zipped, and the STL files can be opened with a variety of software. Unfortunately, STL looks to be a binary format, and it’s not clear to me after a few minutes of searching if there’s a trivially printed text format. But that’s a very low hurdle.

As Doctorow implied, reasonableness on all sides would be nice to have. But at home printing isn’t going to go away, and censorship orders are not a productive step forward.

[Previously here: “What Should a Printer Print?“]