July 2018 - cypherpunks-legacy

[cryptography] summary of zerocoin (Re: an untraceability extension to Bitcoin using a combination of digital commitments, one-way accumulators and zero-knowledge proofs, )
by Adam Back 06 Jul '18

06 Jul '18

It appears to use cut-and-choose technique to create a non-interactive ZKP on a one-way accumulator (from Camenisch & Lysanka). That results in relatively big ZKPs which impact bitcoin scalability, it doesnt say how big they actually are but for good security margin I'm guessing something like 128 individual proofs, which can get kind of heavy. They say its like to exceed the bitcoins 10kb per tx limit. (People may recall cut-and-choose as Chaum's original blind RSA signature based proposal to support offline spendable ecash with identity exposure as the penalty - the owners identity would be embedded in the coin via cut and choose, and then if they double spend revealed as ther is some recipient choice within the spend that would reveal two shares). Stefan Brands ecash by contrast with the more flexible discrete log representation problem provided a direct (non-cut-and-choose) offline double spend deterrence method. (Cut and choose is a simple idea that if you have to commit first and reveal one of two options you have a 1 in 2 (0.5 or 2^-1) chances of cheating (and putting someone elses identity in the coin eg for revealing during an offline double spen), but if you do it 128 times you have a 2^-128 chance of cheating. The same approach plus demonstrably fair way to generate witnesses is a general method for constructing NIZKPs from ZKPs.) Also in principle you have to construct a NIZKP all the way back to the first zerocoin, and while the accumulator is constructed incrementally and stored in each block bitcoin requires public auditability so the verifier has to go check the corresponding "spent" list that grows. (The ZKP is that the zerocoin is a member of the set of zerocoins previously exchanged for bitcoin, and is not a member of the spent list. The expensive part is the former, the latter is just a bit list of spent zerocoin serial numbers. Thy do suggest just trusting the last block accumulator as a starting point, but I think you can only do that if the zerocoin was issued after that, and the effectiveness of that optimization is in some conflict with anonymity set requiremnts to hold the zerocoin for a while to at least have a decent number of coins your mixin with. The accumulators allow faster NIZP of set membership than proving with a bit list of OR operations, but the cut-and-choose itself isnt a direct NiZKP it involves 128 rounds or whatever the security parameter is. The accumulator uses a trusted party to generate an RSA key and discard the private keys. (Though happily there are RSA UFOs (way to generate an RSA key without ever knowing the private key in a trustworthy way)). So thats all pretty cool, and I think an efficiency improvement over previous NIZKP of set membership (or non-set-membership) but a bit heavy. btw about payment privacy (or lack thereof in bitcoin) an amusing link http://www.listentobitcoin.com/ to get an idea of the bitcoin transaction volume and transaction sizes - highlighting visually the extremely open nature of the realtime transaction history. I saw a massive $640k transaction float past when I looked. Soothing sounds it makes too. (Bitcoin is private only in the self chosen psuedonym sense, and is otherwise an open book by design). Adam On Sat, Apr 13, 2013 at 01:40:36AM +0300, ianG wrote: > Steve Bellovin posted this on another list, hattip to him. > > http://www.forbes.com/sites/andygreenberg/2013/04/12/zerocoin-add-on-for-bi… > > For those following Bitcoin this is news. Matthew Green writes: > > For those who just want the TL;DR, here it is: > > Zerocoin is a new cryptographic extension to Bitcoin that (if > adopted) would bring true cryptographic anonymity to Bitcoin. It works > at the protocol level and doesn't require new trusted parties or > services. With some engineering, it might (someday) turn Bitcoin into a > completely untraceable, anonymous electronic currency. > > http://blog.cryptographyengineering.com/2013/04/zerocoin-making-bitcoin-ano… > > > > (iang adds:) > > Bitcoin is psuedonymous but traceable, which is to say that all > transactions are traceable from identity to identity, but those > identities are psuedonyms, being (hashes of) public keys. This is > pretty weak. In contrast, Chaumian blinding was untraceable but > typically identified according to an issuer's regime. Because Chaumian > mathematics required a mint, this devolved to trusted/identified, so > again not as strong as some hoped. > > Bitcoin fixed this 'flaw' by decorporating the mint into an algorithm. > This suggests a new axis of distributed. But Bitcoin lost the > untraceability in the process, thus rendering it a rather ridiculous > attempt at privacy, as the entire graph was on display. Bitcoin is more > or less worse at privacy than Chaumian cash ever was. > > The holy grail in Chaumian times was untraceable & unidentifiable, to > which Bitcoin added distributed. This paper by Miers, Garman, Green & > Rubin suggests untraceable & psuedonymous & distributed is possible: > > http://spar.isi.jhu.edu/~mgreen/ZerocoinOakland.pdf > > (I haven't as yet read the paper so there may be killer details in there.) > > > iang > _______________________________________________ > cryptography mailing list > cryptography(a)randombit.net > http://lists.randombit.net/mailman/listinfo/cryptography _______________________________________________ cryptography mailing list cryptography(a)randombit.net http://lists.randombit.net/mailman/listinfo/cryptography ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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Electronic Voting: Danger and Opportunity
by Ali, Saqib 06 Jul '18

06 Jul '18

University of Illinois will hold a talk on "Electronic Voting: Danger and Opportunity". Professor Edward W. Felten of Princeton University will be speaking.See: http://webtools.uiuc.edu/calendar/Calendar?calId=504&eventId=78090&ACTION=V… saqib http://www.quantumcrypto.de/dante/ --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo(a)metzdowd.com ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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[Politech] Feds mull mandatory data retention laws for Internet service providers [priv]
by Declan McCullagh 06 Jul '18

06 Jul '18

I've put a copy of the Colorado legislation here: http://www.politechbot.com/docs/colorado.data.retention.041206.pdf Previous Politech messages: http://www.politechbot.com/2005/06/16/feds-contemplate-forcing/ http://www.politechbot.com/2005/09/23/european-commission-proposes/ http://www.politechbot.com/p-02779.html -Declan --- http://news.com.com/ISP+snooping+gaining+support/2100-1028_3-6061187.html ISP snooping gaining support April 14, 2006, 4:03 AM PDT The explosive idea of forcing Internet providers to record their customers' online activities for future police access is gaining ground in state capitols and in Washington, D.C. Top Bush administration officials have endorsed the concept, and some members of the U.S. Congress have said federal legislation is needed to aid law enforcement investigations into child pornography. A bill is already pending in the Colorado State Senate. Mandatory data retention requirements worry privacy advocates because they permit police to obtain records of e-mail chatter, Web browsing or chat-room activity that normally would have been discarded after a few months. And some proposals would require providers to retain data that ordinarily never would have been kept at all. [...] Flint Waters, head of the Wyoming's Internet Crimes Against Children task force, also is pressing for federal data retention laws... "Individuals will activate their Webcam when they're abusing a child and they'll record the sexual assault live, and it may be 45 days before law enforcement finally gets notified," Waters said. "We reach out to service providers and they say they don't maintain those records, so the child remains in that environment, and there's nothing we can do to help them." [...] _______________________________________________ Politech mailing list Archived at http://www.politechbot.com/ Moderated by Declan McCullagh (http://www.mccullagh.org/) ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]

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[Politech] FBI illegal use of eavesdropping powers: not just national security letters [priv]
by Declan McCullagh 06 Jul '18

06 Jul '18

So we've all heard about the FBI's misuse of national security letters. The Justice Department's inspector general came out with a report on March 9 describing "serious misuse" of the letters, which are secret subpoena-like documents that can be sent to businesses including banks, telephone companies, and ISPs: http://www.usdoj.gov/oig/special/s0703b/final.pdf I wrote about the inspector general's report here: http://news.com.com/2100-1028_3-6166015.html And in fact the inspector general, Glenn Fine, is going to be testifying about them in the Senate on Wednesday at 10am ET: http://judiciary.senate.gov/hearing.cfm?id=2616 Fine showed up before a House committee on Tuesday and faced a hostile audience -- not that the FBI's illegal acts are his fault, mind you, but Bush administration officials seem oddly reluctant to testify in public under oath nowadays: http://www.washingtonpost.com/wp-dyn/content/article/2007/03/20/AR200703200… The odd thing is that everyone, or nearly everyone, seems to think this is entirely unexpected. In fact, it's a natural consequence of giving the federal government more and more power over the years (national security letters were made much more powerful by the Patriot Act). Incentives matter, and the FBI has plenty of incentives to expand its power and surveillance ability and precious few incentives to preserve Americans' constitutional liberties. To give credit to EPIC, they realized this and sent a letter to the Senate in June 2006 asking for more oversight: http://www.epic.org/privacy/surveillance/sen_iob_letter.pdf So have libertarian writers, who for years have called national security letters "the ultimate constitutional farce," which is about right. The letters represent FBI agents _authorizing themselves_ to seize information without bothering to get a judge's approval, after all: http://www.lewrockwell.com/orig6/napolitano2.html Occasionally other evidence about illegal FBI eavesdropping comes to light, which is what I described in an article published two days before the DOJ's report: http://news.com.com/2100-1039_3-6165067.html That article outlines how FBI agent Scott Wenther submitted a 42-page sworn affidavit that was intentionally designed to mislead the court into approving what a judge called an "illegal" wiretap. I've put the some of the court documents here: http://politechbot.com/docs/fbi.agent.scott.wenther.affidavit.030607.txt http://politechbot.com/docs/fbi.wenther.opinion.030607.pdf http://politechbot.com/docs/fbi.wenther.defendant.brief.030607.pdf This is of course the same federal police agency that is using our tax dollars to lobby Congress to mandate data retention, which should make us think twice about how _that_ nice part of the surveillance apparatus will be used and misused: http://www.politechbot.com/2007/01/24/not-just-isps/ -Declan _______________________________________________ Politech mailing list Archived at http://www.politechbot.com/ Moderated by Declan McCullagh (http://www.mccullagh.org/) ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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Electronic Voting: Danger and Opportunity
by Ali, Saqib 06 Jul '18

06 Jul '18

University of Illinois will hold a talk on "Electronic Voting: Danger and Opportunity". Professor Edward W. Felten of Princeton University will be speaking.See: http://webtools.uiuc.edu/calendar/Calendar?calId=504&eventId=78090&ACTION=V… saqib http://www.quantumcrypto.de/dante/ --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo(a)metzdowd.com ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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[Politech] Feds mull mandatory data retention laws for Internet service providers [priv]
by Declan McCullagh 06 Jul '18

06 Jul '18

I've put a copy of the Colorado legislation here: http://www.politechbot.com/docs/colorado.data.retention.041206.pdf Previous Politech messages: http://www.politechbot.com/2005/06/16/feds-contemplate-forcing/ http://www.politechbot.com/2005/09/23/european-commission-proposes/ http://www.politechbot.com/p-02779.html -Declan --- http://news.com.com/ISP+snooping+gaining+support/2100-1028_3-6061187.html ISP snooping gaining support April 14, 2006, 4:03 AM PDT The explosive idea of forcing Internet providers to record their customers' online activities for future police access is gaining ground in state capitols and in Washington, D.C. Top Bush administration officials have endorsed the concept, and some members of the U.S. Congress have said federal legislation is needed to aid law enforcement investigations into child pornography. A bill is already pending in the Colorado State Senate. Mandatory data retention requirements worry privacy advocates because they permit police to obtain records of e-mail chatter, Web browsing or chat-room activity that normally would have been discarded after a few months. And some proposals would require providers to retain data that ordinarily never would have been kept at all. [...] Flint Waters, head of the Wyoming's Internet Crimes Against Children task force, also is pressing for federal data retention laws... "Individuals will activate their Webcam when they're abusing a child and they'll record the sexual assault live, and it may be 45 days before law enforcement finally gets notified," Waters said. "We reach out to service providers and they say they don't maintain those records, so the child remains in that environment, and there's nothing we can do to help them." [...] _______________________________________________ Politech mailing list Archived at http://www.politechbot.com/ Moderated by Declan McCullagh (http://www.mccullagh.org/) ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]

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[Politech] FBI illegal use of eavesdropping powers: not just national security letters [priv]
by Declan McCullagh 06 Jul '18

06 Jul '18

So we've all heard about the FBI's misuse of national security letters. The Justice Department's inspector general came out with a report on March 9 describing "serious misuse" of the letters, which are secret subpoena-like documents that can be sent to businesses including banks, telephone companies, and ISPs: http://www.usdoj.gov/oig/special/s0703b/final.pdf I wrote about the inspector general's report here: http://news.com.com/2100-1028_3-6166015.html And in fact the inspector general, Glenn Fine, is going to be testifying about them in the Senate on Wednesday at 10am ET: http://judiciary.senate.gov/hearing.cfm?id=2616 Fine showed up before a House committee on Tuesday and faced a hostile audience -- not that the FBI's illegal acts are his fault, mind you, but Bush administration officials seem oddly reluctant to testify in public under oath nowadays: http://www.washingtonpost.com/wp-dyn/content/article/2007/03/20/AR200703200… The odd thing is that everyone, or nearly everyone, seems to think this is entirely unexpected. In fact, it's a natural consequence of giving the federal government more and more power over the years (national security letters were made much more powerful by the Patriot Act). Incentives matter, and the FBI has plenty of incentives to expand its power and surveillance ability and precious few incentives to preserve Americans' constitutional liberties. To give credit to EPIC, they realized this and sent a letter to the Senate in June 2006 asking for more oversight: http://www.epic.org/privacy/surveillance/sen_iob_letter.pdf So have libertarian writers, who for years have called national security letters "the ultimate constitutional farce," which is about right. The letters represent FBI agents _authorizing themselves_ to seize information without bothering to get a judge's approval, after all: http://www.lewrockwell.com/orig6/napolitano2.html Occasionally other evidence about illegal FBI eavesdropping comes to light, which is what I described in an article published two days before the DOJ's report: http://news.com.com/2100-1039_3-6165067.html That article outlines how FBI agent Scott Wenther submitted a 42-page sworn affidavit that was intentionally designed to mislead the court into approving what a judge called an "illegal" wiretap. I've put the some of the court documents here: http://politechbot.com/docs/fbi.agent.scott.wenther.affidavit.030607.txt http://politechbot.com/docs/fbi.wenther.opinion.030607.pdf http://politechbot.com/docs/fbi.wenther.defendant.brief.030607.pdf This is of course the same federal police agency that is using our tax dollars to lobby Congress to mandate data retention, which should make us think twice about how _that_ nice part of the surveillance apparatus will be used and misused: http://www.politechbot.com/2007/01/24/not-just-isps/ -Declan _______________________________________________ Politech mailing list Archived at http://www.politechbot.com/ Moderated by Declan McCullagh (http://www.mccullagh.org/) ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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Re: [tor-talk] Tor and P2P
by adrelanos 06 Jul '18

06 Jul '18

grarpamp: > Given that these services are surely coming in force... and from > directions that see these networks more as a raw transport than > say, primarily for the purposes outlined on their respective web > pages... it seems the usual echo of "we're a nice project, don't > do that, too much load" may not be useful. This should not imply > fault, but merely suggest that it's dated and hopeless. I tend to agree but I am not sure. At the moment I don't believe the Tor project will die soon. It's fine with me if we can continue use it for anonymous browsing, circumvention and so on for the next years. It's also questionable if the Tor project should try to get a big share of the people interested in anonymous p2p. I tend to think no, because this opens up the project for a lot negative press. That increases the risk for a new law to forbid the whole network in even more countries. Let other networks try that out. > P2P services should look at the current strong anonymization projects > that could provide transport. The ones I know of are: > > http://www.i2p2.de/ > https://code.google.com/p/phantom/ > https://www.torproject.org/ > > More links are welcome. Loads of links here: https://en.wikipedia.org/wiki/Anonymous_P2P A very interesting idea is/was the owner free filesystem: https://en.wikipedia.org/wiki/OFFSystem Depending on ones individual threat model, I believe i2p could be sufficiently secure for file sharing purposes: http://www.i2p2.de/ I didn't make an academic comparison, but it looks like retroshare is quickly gaining more and more users: http://retroshare.sourceforge.net/ _______________________________________________ tor-talk mailing list tor-talk(a)lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE

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Conspiracy Theory O' The Day
by Udhay Shankar N 06 Jul '18

06 Jul '18

I just got a batch of spam: perfectly justified blocks of random-looking characters. Makes me wonder if somebody is trying to train Bayesian filters to reject PGP messages. Udhay -- ((Udhay Shankar N)) ((udhay @ pobox.com)) ((www.digeratus.com)) --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo(a)metzdowd.com --- end forwarded text -- ----------------- R. A. Hettinga <mailto: rah(a)ibuc.com> The Internet Bearer Underwriting Corporation <http://www.ibuc.com/> 44 Farquhar Street, Boston, MA 02131 USA "... however it may deserve respect for its usefulness and antiquity, [predicting the end of the world] has not been found agreeable to experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'

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ccml Trauma management in Iraq
by Eric Hodgson 06 Jul '18

06 Jul '18

The Journey Through Trauma U.S. troops who survive the critical 'golden hour' after being seriously wounded in Iraq owe their lives to a fast-acting team of battlefield medics, pilots, nurses and surgeons. By David Zucchino, LA Times Staff Writer April 3, 2006 http://www.latimes.com/news/nationworld/nation/la-na- wounded3apr03,0,3069118.story As Lance Cpl. Ryan Buchter lay bleeding in the Iraqi desert, his fate hinged on the efficiency of a medical lifeline that stretches halfway around the world. From that moment forward, hundreds of strangers would work to save him. Buchter's platoon was in a village called Husaybah on Nov. 8, searching for the enemy. He was standing in the doorway of a farmhouse when an insurgent inside rolled a grenade at his feet. ADVERTISEMENT The explosion shredded Buchter's left leg as superheated shrapnel tore through muscles and tendons. More shrapnel crushed his right hand and sliced into his nasal cavity. Buchter groped for his nose but couldn't feel it. He thought it had been blown off. He leg was so shattered that he was certain he would lose it, and he imagined being left crippled at age 20. "And not once did I cry," he recalled later, "until I thought, like, I was going to lose my leg and stuff." A Marine applied a pressure bandage to Buchter's leg, trying to stop the bleeding. Another wrapped his hand and pressed gauze against his pulverized nose. The Marines quickly loaded Buchter into an armored vehicle, which delivered him to a medical aid station nearby. Buchter survived the "golden hour" the 60 minutes following a serious battlefield wound, when the speed and competence of emergency treatment can mean the difference between life and death. Ordinary fighting men teamed with doctors, surgeons and nurses to keep him alive. His fellow Marines what the military calls his "battle buddies" were able to stanch his bleeding by putting their combat lifesaving training to quick use. Exsanguination, or bleeding to death, is the leading cause of death for American troops in Iraq. As a military doctor examined his leg inside the aid station, Buchter was alarmed by the concerned look on the man's face. "If I lose my leg, I'm coming back to get you," he told him. The doctor assured Buchter that his leg would be saved. "You've got my word," he said. Then a surgeon arrived and warned Buchter that he might indeed lose his leg. The best option to save it, he told him, was a very painful and sometimes disfiguring surgery called a fasciotomy, the extensive cutting and cleaning of the wound. "And I was like, 'Cut me up if you have to. I just don't want to lose my leg,' " Buchter recalled. The medical odyssey of this Marine was just beginning. Buchter was now a patient in a virtual assembly line of care. It begins with soldiers and medics on the battlefield and shifts quickly to helicopter crews who pluck the wounded from kill zones. It continues to surgeons and nurses and X-ray technicians at desert facilities, and to virtual flying hospitals that airlift the wounded from Balad to a U.S. military hospital in Germany. It leaps the Atlantic to major military medical centers in Texas and Washington, D.C. It passes through military hospitals from New York to California. It culminates with months of painstaking physical and occupational therapy in hospital wards and private homes. About 17,400 wounded have been treated since the war began three years ago. The fulcrum for treatment in Iraq is the U.S. Air Force Theater Hospital in Balad. In addition to the troops brought directly to the hospital, any seriously wounded American must make a stop in Balad to be flown for treatment in Germany. The facility is housed inside three dozen tents and three trailers on the packed sands of a former Iraqi air force base 50 miles north of Baghdad. Sandbags, concrete blast walls and concertina wire provide protection from insurgents, car bombs and mortars. The military says no injured American is more than 30 minutes from Balad or one of three combat support hospitals operated by the Army. The rapid evacuation of wounded troops begins with Black Hawk medevac crews of four nicknamed "dust-off" teams trained to respond rapidly to distress calls from the battlefield. >From their dusty tent base about a mile from the hospital, the Army air ambulance companies keep three helicopters and crews ready at all times. The copters occupy a corner of the air base, the thumping of their rotors competing with the roar of F-16s taking off and the low hum of armed reconnaissance drones. The crews are called to action by "nine-lines," the emergency radio calls from the battlefield that provide nine essential bits of information: location, number of wounded, whether the landing zone is "hot," or under fire, and so on. In most cases, the crews say, their helicopters lift off within eight to 10 minutes ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]

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