[HN Gopher] Eagle Cash
       ___________________________________________________________________
        
       Eagle Cash
        
       Author : enjoyyourlife
       Score  : 127 points
       Date   : 2021-01-01 07:43 UTC (15 hours ago)
        
 (HTM) web link (en.wikipedia.org)
 (TXT) w3m dump (en.wikipedia.org)
        
       | jpkoning wrote:
       | The US military has had some innovative payments ideas.
       | 
       | An occupying force prefers to use a money that 1) doesn't
       | dollarize the nation they are occupying 2) can be tracked, thus
       | thwarting black marketeers 3) is lightweight 4) if they lose, the
       | enemy can't reuse it
       | 
       | Unfortunately, dollar bills are bulky, infiltrate local
       | economies, and aren't enemy-resistant.
       | 
       | So we get innovations like EagleCash, which solves a lot of these
       | problems.
       | 
       | Other payments ideas emanating from the military include Military
       | Payment Certificates
       | (https://jpkoning.blogspot.com/2017/04/c-day-and-military-
       | mon...), overstamped currency (
       | https://twitter.com/jp_koning/status/1343874636480729088) and
       | pogs (http://numispedia.org/AAFES/).
        
         | [deleted]
        
         | md_ wrote:
         | Why is #1 a goal? I'm assuming because of some desire to
         | maintain the independence of a central bank in the occupied
         | country?
        
           | jpkoning wrote:
           | That's right. In the US's case, if it was protecting a
           | weakened friendly country or trying to rebuild a not-so-
           | friendly one, dollarizing the economy would have undermined
           | the occupied government and interfered with the US's overall
           | goals. Using cancellable paper certificates like MPC or a
           | closed loop electronic system like EagleCash prevented
           | leakage of US dollars into the local economy.
        
           | Qub3d wrote:
           | I imagine part of it is reducing the incentive for nation
           | state actors to engage in counterfeiting.[1]
           | 
           | [1]: https://en.wikipedia.org/wiki/Superdollar
        
       | alisonkisk wrote:
       | This is an electronic form of "scrip".
       | 
       | The risk is that it gives the script system owner control over
       | the value of money.
       | 
       | https://en.m.wikipedia.org/wiki/Scrip
        
       | ahelwer wrote:
       | Microsoft uses something similar for their on-campus cafeterias.
       | All Microsoft employees are issued a RFID card with a chip that
       | functions as a door access card, visual ID (it has your
       | photo/name/employee number on it), smartcard for 2FA (this is
       | being phased out in favor of TPM-based device registration), and
       | cafeteria payment system. You can elect to have some percentage
       | of your paycheck automatically loaded on the card. I used it for
       | a bit early on in my employment, but then switched to paying with
       | credit card (like almost everyone else I know).
        
         | 2bitencryption wrote:
         | I think the core difference is that "Eagle Cash" is not
         | centrally managed - the balance is actually on the physical
         | card itself. I imagine the MS cards is more of a "central
         | account" that is accessed when you swipe.
         | 
         | I guess each "Eagle Cash" terminal has a certificate, and
         | whenever you credit/debit the card, the terminal adds/subtracts
         | the amount on the card, signs the new balance with the
         | certificate, and then this can be verified at any other
         | terminal.
         | 
         | In other words, you can't modify the balance on the card unless
         | you have the secret certificate, which is only present on the
         | authorized terminals. If you try to modify it yourself, you
         | can't do it, because no other terminal would accept the card
         | unless the balance was cryptographically signed with the cert.
         | 
         | That's my guess for how this works, at least. I wonder if each
         | terminal has a unique cert that can be revoked if it is
         | compromised.
        
       | KirillPanov wrote:
       | _Unlike regular debit cards, the Eagle Cash is managed on-base,
       | using batch processing which ensures that the cards remained
       | useful even when connections to banks and credit unions State-
       | side are severed._
       | 
       | This is really the whole point, but it's buried in the third
       | paragraph. These cards work when the internet and all other
       | communication with the outside world are down.
       | 
       | Replacing physical currency in that scenario is really difficult.
        
       | a-dub wrote:
       | my laundry room in college used the same technology. sucks if you
       | damage the card (by sitting on your wallet, for example).
        
         | 1-6 wrote:
         | Of maybe like electronic lunch chits. Once they go through the
         | reader, it might 'burn the circuit' being equivalent to
         | stamping a hole into the card.
        
           | avian wrote:
           | Back in the days when public phone booths were still a thing,
           | the local telecom introduced pre-paid chip cards that you
           | used for paying for your call. They were widely advertised as
           | "fraud proof" because the chip physically burned polyfuses on
           | the silicon as credits were used up. You can never restore a
           | card that ran out of credits that way, they said.
           | 
           | It was simple to make a card insert and a circuit that just
           | lied to the phone that a fuse was burned. They switched to a
           | different system soon after.
        
       | ggrelet wrote:
       | Similar topic: https://en.wikipedia.org/wiki/FeliCa
        
       | cbanek wrote:
       | I'm reminded of the episode of M _A_ S*H where they are
       | exchanging one color of scrip for another [0], and the hijinx [1]
       | that ensues.
       | 
       | [0] https://mash.fandom.com/wiki/Change_Day_(TV_series_episode)
       | 
       | [1] Triple word score for a word with three dotted letters in a
       | row.
        
       | josephkern wrote:
       | Wait until you guys see the prices for the "AAFES POGS" on ebay
       | ...
       | 
       | Basically while you can use cash, coins are too heavy to justify
       | shipping into country. AAFES instead prints "gift certificates"
       | in the shape of a pog, in 0.05, 0.10, 0.25 denominations.
       | 
       | The resale value on these is hilariously high ... these are
       | federally issued mediums of exchange being currency except in
       | name only. And only useable in deployed locations.
        
         | bananapear wrote:
         | > in the shape of a pog
         | 
         | In case you are wondering what a "pog" is:
         | 
         | https://en.wikipedia.org/wiki/Milk_caps_(game)
        
           | nefitty wrote:
           | Something I never intended to learn: "pog" is an acronym for
           | "passion fruit - orange - guava".
        
           | cracksmoka420 wrote:
           | Person Other (than) Grunt
        
         | gioscarab wrote:
         | The word medium comes from latin, its plural is "media", not
         | "mediums".
        
           | AndriyKunitsyn wrote:
           | I'm ESL, how far should the "thou should pluralize a loanword
           | as it was in the original language" rule go? It seems to be
           | not universal.
           | 
           | I mean, it's "hamburgers", not "die Hamburger", "robots", not
           | "roboti", and "rubles", not "rubli"/"rubli".
        
             | ouchjars wrote:
             | Borrowed plural forms are most likely to happen with
             | French, Latin, and Greek loans, and also those from
             | languages that don't change words to make them plural, e.g.
             | Japanese and Maori.
             | 
             | Sometimes it happens with other languages, like the use of
             | Hebrew plural rules for cherub/cherubim, but there's the
             | best approximation.
        
               | majewsky wrote:
               | > Sometimes it happens with other languages, like the use
               | of Hebrew plural rules for cherub/cherubim
               | 
               | For what it's worth, the few times I've seen the plural
               | of cherub in the English language (mostly in song
               | lyrics), it was always "cherubs", not "cherubim". Not
               | saying the latter wouldn't be acceptable: Wiktionary
               | lists both.
        
             | unscaled wrote:
             | This is mostly relegated to Latin and some Greek plurals:
             | 
             | Latin:                 stimulus/stimuli, fungus/fungi (2nd
             | declension masculine)       medium/media (2nd declension
             | neuter)       alga/algae, larva/larvae (1st declension)
             | index/indices (3rd declension)
             | 
             | Greek:                 phenomenon/phenomena,
             | criterion/criteria (2nd declension neuter)
             | analysis/analyses (3rd declension, I think proper Greek and
             | Latin would actually be 'analyseis')
             | 
             | Latin and Greek were the classical languages that were
             | expected to be spoken by the educated upper class in 19th
             | century Anglo-Saxon world (the British Empire and the US).
             | Most of the present day language conventions we have were
             | gradually developed throughout the 17th to 19th centuries,
             | as a result of print becoming established. Before that,
             | English spelling varied greatly from text to text and the
             | even the English plural themselves were determined by the
             | writer's dialect, as in this example by William Caxton
             | (England's first printer) in 1490 (in modernized spelling):
             | 
             | In modern spelling:
             | 
             | "And specially he asked after 'egges'. And the good wife
             | answered that she could speak no French. And the merchant
             | was angry for he also could speak no French, but would have
             | had 'egges' and she understood him not. And then at least
             | another said that he would have 'eyren'. Then the good ife
             | said she understood him well.
             | 
             | The original splling was[1]:
             | 
             | "And specyally he axyed after eggys. And the good wyf
             | answerde that she coude speke no frenshe. And the marchaunt
             | was angry for he also coude speke no frenshe but wold haue
             | hadde egges and she understode hym not. And thenne at laste
             | a nother sayd that he wolde haue eyren. Then the good wyf
             | sayd that she understood hym we."
             | 
             | During the period of standardization, it was the educated
             | class I mentioned before that influenced spelling the most.
             | Up to the 19th century they were expected to have a good
             | grasp of Latin (and sometimes Greek) grammar, which is why
             | "Grammar Schools" existed (originally meant to teach Latin
             | grammar). Latin remained a requirement in some Elite
             | schools and universities (like Oxford and Cambridge) well
             | into the mid 20th century. This explains why the standard
             | setters were quite pedantic about pluralizing Latin (and
             | sometimes Greek) nouns correctly, but gave themselves a
             | free hand in mutilating plurals (and even the words
             | themselves) in other languages.
             | 
             | Since most of the educated upper class didn't know Ancient
             | Greek as well as Latin, you find that Greek plural usage is
             | not as systemic as Latin. That's why we're missing the
             | first declension (we do not pluralize catastrophe as
             | _catastrophai, we say dogmas and not_ dogmata, atlases and
             | not _atlantes) and second declension masculine (cosmos is
             | pluralized as cosmoses, not_ cosmoi). On the other hand,
             | the high classes in the 19th century often spoke French and
             | Italian, which is why it used to be fashionable to have
             | some pluralizations such as -eau/eaux (bureau/bureaux) and
             | -o/i (virtuoso/virtuosi). I feel like this is not so
             | faddish anymore.
             | 
             | It's also important to note that the words we're covering
             | here are _learned words_ - which are more influenced by
             | elitist tendencies, since they first appear in print in
             | academic publications and newspapers, before finding their
             | way into everyday speech (if at all). Early borrowed words
             | from Latin that have long become colloquial by then like
             | wine (vinum/vina), pillow (pulivnus/pulvini) dish
             | (discus/disci) and pound (pondus/pondera) don't even much
             | the Latin singular form and are sometimes barely
             | recognizable.
             | 
             | tl;dr: The explanation has to do mostly with elitist
             | tendencies and the particular languages the elite during
             | the time of standardization knew well and happened to care
             | about. There are many exceptions.
             | 
             | The best rule of thumb is that learned Latin words are
             | mostly pluralized as in Latin, Greek words are pluralized
             | as in Greek only with certain suffixes (-on/a and -sis/ses)
             | and very rarely with any other language.
             | 
             | The second rule of thumb to remember is that once a Latin
             | or Greek word becomes colloquial, the foreign plural is
             | often used in conjunction with a native English plural or
             | becomes abandoned completely. To use medium as an example:
             | 
             | Academic usage:                 * means of communication
             | (media) - 'mass medium' is almost always pluralized 'mass
             | media'       * material conductor (e.g. air as medium) -
             | usually 'media'
             | 
             | Colloquial usage:                 * average, in the middle
             | - usually mediums       * someone who communicates with
             | spirits and ghosts - always mediums
             | 
             | [1] https://www.bl.uk/learning/timeline/item126611.html
        
             | jcranmer wrote:
             | > I'm ESL, how far should the "thou should pluralize a
             | loanword as it was in the original language" rule go? It
             | seems to be not universal.
             | 
             | The basic rule of thumb is: assume it doesn't apply. That
             | is, for most foreign words, -(e)s is usually an acceptable
             | plural word, and even if it isn't, people will understand
             | what you mean.
        
             | spindle wrote:
             | Right! I especially like your Russian example.
             | 
             | There is no general rule. Life sucks.
        
           | [deleted]
        
           | Retric wrote:
           | While some sources agree with you:
           | https://www.thefreedictionary.com/mediums
           | 
           | Both Media and Mediums are plural forms in common usage.
           | Thus: https://www.merriam-webster.com/thesaurus/mediums has
           | mediums variants: or media plural of medium
           | 
           | ex: https://www.uspto.gov/kids/MiddleSchool-
           | HowWellSoundTravels....
           | 
           | And really, English just evolves over time so these kind of
           | rules don't actually mean anything.
        
             | err4nt wrote:
             | Though English has two plural forms "media" and "mediums",
             | are they interchangeable? If you say "media" I think of
             | more than one medium of communication, but if you say
             | "mediums" I think of a group of humans who engage in
             | necromancy and talking to spirits and stuff (being a medium
             | as a job)
        
               | Retric wrote:
               | I believe it's context specific. Both are in common use
               | in acoustics or bacterial cultures, but it's electronic
               | media and spirit mediums.
        
             | gioscarab wrote:
             | Here in Italy (that is where the word was invented in the
             | first place) that is considered a bad common mistake.
             | Forgetting about the etymology or misusing a word is not
             | what I would define as "evolution". We say multi-media,
             | mass-media ecc. for a reason, for the same reason we don't
             | say multi-mediums or mass-mediums.
        
               | gpderetta wrote:
               | To be pedantic, the correct grammatical rule in italian
               | is that foregin words (including latin) are kept
               | invariant between singular and plural, so the plural of
               | medium would still be medium.
               | 
               | This rule is of course often misapplied, especially for
               | latin words.
        
               | Retric wrote:
               | That's the thing, in English when enough people make a
               | mistake it stops being a mistake.
        
           | howlgarnish wrote:
           | The word "media" has become shorthand for "communications
           | media". While correct in the original Latin, trying to use
           | "media" as the plural for "medium" in any other context in
           | English is jarring.
        
             | gioscarab wrote:
             | The word medium identifies a mean of communication. The
             | commenter uses it to identify a mean of exchanging value.
             | IMHO the word was both misused and misspelled.
        
               | howlgarnish wrote:
               | "Medium of exchange" is standard terminology in
               | economics.
               | 
               | https://en.wikipedia.org/wiki/Medium_of_exchange
        
               | gioscarab wrote:
               | You are right! So just misspelled :)
        
               | [deleted]
        
       | zapdrive wrote:
       | With upcoming satellite internet projects (see Starlink), I think
       | it will be highly unlikely to disconnect any army base totally
       | from the internet. In such scenarios, any centralized service
       | would be much more efficient, secure and convenient. Soldiers can
       | also use cryptocurrencies for trade among themselves, without
       | needing to carry cash.
        
         | lnanek2 wrote:
         | So what about during war when the enemy may have shot down your
         | sats? Your soldiers are still going to want to buy goods on
         | base during their down time and morale will suffer if you just
         | tell them the internet is down.
        
           | zapdrive wrote:
           | How many will they shoot down? SpaceX is launching them by
           | hundreds every month. The end goal is 45000 satellites. And
           | by shooting just a few, the enemy will maybe only slow down
           | the internet, not turn it off completely.
           | 
           | Let that sink in. They'll need 45000 missiles up shoot down
           | every starlink satellite. Also, SpaceX will definitely be
           | launching new ones as they are being shot down. So it's a
           | very impractical approach.
        
       | pram wrote:
       | Huh. I was in the Air Force from 2005-2010 and I literally never
       | saw this. I was at LSA Anaconda in Iraq too (mentioned in the
       | article) ... must be an Army thing?
        
         | studius wrote:
         | Eagle Cash makes me think of something related to the World
         | Space Commission[1][2].
         | 
         | But, apparently the US Dept. of the Treasury[3] manages three
         | kinds of payment cards, EZPay, EagleCash, and Navy Cash.
         | 
         | Both the Army and Air Force use EagleCash[4][5].
         | 
         | There may have been some consolidation[6], but EZPay and Navy
         | Cash still seem to have presence[7][8].
         | 
         | Note: previously there were four programs[9], once of which was
         | Marine Cash.
         | 
         | [1]- https://en.wikipedia.org/wiki/Space:_1999
         | 
         | [2]- https://paizo.com/threads/rzs2jizp?Space-1999The-Thirty-
         | year...
         | 
         | [3]- https://en.wikipedia.org/wiki/Stored-value_card
         | 
         | [4]- https://www.af.mil/News/Article-
         | Display/Article/122557/eagle...
         | 
         | [5]-
         | https://www.fiscal.treasury.gov/eaglecash/organizations.html
         | 
         | [6]- https://www.usafmcom.army.mil/News/Article-
         | Display/Article/1...
         | 
         | [7]- https://fiscal.treasury.gov/ezpay/
         | 
         | [8]- https://fiscal.treasury.gov/navy-cash/
         | 
         | [9]- https://www.secureidnews.com/news-item/us-military-relies-
         | on...
        
         | xedeon wrote:
         | It was used in the Air Force as well. It was issued in Basic
         | Training and deployed locations.
         | 
         | https://www.dvidshub.net/image/44435/eagle-cash-has-landed-a...
         | 
         | https://www.af.mil/News/Photos/igphoto/2000452297/
         | 
         | https://www.afcent.af.mil/Units/332nd-Air-Expeditionary-Wing...
        
           | pram wrote:
           | I'm not denying it exists (it's obviously a thing) but when I
           | went through basic, they had us bring a voided check to set
           | up direct deposit. We never had anything like this. Also I
           | used my USAA debit card with zero issues while deployed in
           | Iraq/Afghanistan/Kyrgyzstan. Very strange!
        
       | dibujante wrote:
       | Wait until you see what you can use your metro card for in
       | Taipei...
        
         | odiroot wrote:
         | Isn't this the same as Octopus in HK or FlashPay in Singapore?
        
         | lxgr wrote:
         | Many countries have (or used to have) similar stored-value
         | cards. They are really useful for some use cases: Given that
         | they are very cash-like (transferable, anonymous unless
         | registered), they are usually available to foreigners and
         | minors without any formalities.
         | 
         | Japan's version could at one point even be used to purchase
         | games in Nintendo's eStore by tapping a transit card on a game
         | console - genius, given that a big part of their target
         | audience doesn't have a credit or debit card.
        
       | fallingfrog wrote:
       | This was a common practice in the 19th century, paying workers in
       | company chit that was only good at the company store. The
       | practice might come back if the economic conditions are right.
        
       | max_ wrote:
       | Interesting.
       | 
       | How does this thing solve the "double spend problem" [0].
       | 
       | Without needing network access?
       | 
       | You usually need server communication in electronics payment
       | systems to confirm payment & update account balances. How does
       | Eagle Cash solve this problem?
       | 
       | [0]: https://www.investopedia.com/terms/d/doublespending.asp
        
         | lcabral wrote:
         | This uses the same flow as many transportation cards (which in
         | some countries can also be used to purchase goods). Essentially
         | the card chip holds the debit amount it has (the user makes an
         | initial transaction to load it, debiting the money from a
         | debit/credit card or paying for directly with money) so that
         | every time a transaction occurs, the value in card is altered
         | directly. This system also has the potential of making
         | transactions fully anonymous as no-one needs to know who the
         | holder of the card is or where he spends his money.
        
         | KirillPanov wrote:
         | The card chips are issued by a trusted central authority and
         | (supposedly) tamperproof.
         | 
         | You can't "run EagleCash" on your laptop; it only runs on card
         | chips issued by the military.
        
         | murderfs wrote:
         | You trust the secure element, and if you think that's not
         | enough, you reconcile spending logs and bring the wrath of the
         | federal government on whoever was dumb enough to try.
        
         | 0x426577617265 wrote:
         | Funds are stored on the card and loaded from a kiosk.
        
           | smhg wrote:
           | Something similar existed in Belgium from 1995 to 2014 for
           | small payments, called Proton [0].
           | 
           | [0] https://en.wikipedia.org/wiki/Proton_(bank_card)
        
             | eecc wrote:
             | Also Chipnik in NL, discontinued several years ago. Too
             | fiddly, nobody worries about privacy any longer.
             | 
             | https://en.m.wikipedia.org/wiki/Chipknip
        
               | flemhans wrote:
               | And Danmont in Denmark, 1991-2005.
               | 
               | I think Sweden had one called Kash or something like
               | that.
        
             | fuzzy2 wrote:
             | In Germany, there's GeldKarte. Still relatively widely
             | supported on public transportation ticket machines and
             | cigarettes vending machines, so they can be used offline.
             | 
             | I found it awesome to use with at-home recharging (with an
             | appropriate card terminal) and use on trains. Often, the
             | ticket machine would refuse coins or not have change.
             | Electronic payment to the rescue! :)
             | 
             | Unfortunately, its fate is already sealed with basically
             | all banks having announced their withdrawal from the
             | system.
             | 
             | https://en.wikipedia.org/wiki/Geldkarte
        
         | alasdair_ wrote:
         | They rely on the fact that the double spenders are easy to find
         | and punish.
        
           | max_ wrote:
           | So security is maintained using violence? Not technology?
        
             | murderfs wrote:
             | I find it hilarious that someone running a "fintech studio"
             | doesn't understand this.
        
             | est31 wrote:
             | I think that's the entire point of any army :). In this
             | instance I guess the military police would be responsible
             | though.
             | 
             | It's a centralized system, and every account holder is
             | fully identified to the government (even with DNA samples
             | IIRC). The kiosks likely keep the logs and upload them when
             | a connection can be made. Then the data get collected and
             | compared centrally, and any discrepancy would show up. At
             | least that's how I understand the "batch processing" remark
             | in the wiki page.
        
             | [deleted]
        
             | eecc wrote:
             | What do you think society is all about? I can recommend
             | Debt by the late David Graeber
        
               | lucb1e wrote:
               | Not sure a whole book is needed, it seems fairly
               | straightforward to show that society is based on threats
               | of violence.
               | 
               | If you don't pay someone, that someone can go to a judge.
               | If you indeed did something illegal (e.g. if you did a
               | double spend, money forgery, whatever) you should be
               | declared guilty and ordered to pay the damages plus
               | perhaps a fine. If you don't do that, the amount due will
               | increase and eventually you get ordered to jail. If you
               | don't go voluntarily, they will make you. Of course
               | everything comes down to force and eventually violence in
               | the end. Why else would you comply with things that don't
               | please you? (Because you're an honest party, okay, and
               | the vast majority of people are, but not everyone is in
               | the privileged position where they have what they want
               | without applying dishonesty.)
               | 
               | Even if you think to solve it with technology, preventing
               | a crime is indeed better than detecting and punishing
               | one, but let's say it's impossible to detect the double
               | spend ahead of time and your technological solution only
               | finds out that there was a double spend after the fact.
               | What's it going to do, block your card from now on? In
               | the end, it will still have real world consequences for
               | you. Taking away someone's card, through physical or
               | technological means, it's all more or less the same
               | thing.
        
               | max_ wrote:
               | One reason I am interested in Bitcoin is that it doesn't
               | rely on violence to enforce it's rules.
        
               | texse wrote:
               | If someone can round up 51% of Bitcoin's miners and hold
               | them at gunpoint, then they have full control over
               | Bitcoin's rules.
               | 
               | Well over 51% of bitcoin mining happens in China, so Xi
               | Jinping can probably change Bitcoin's rules tomorrow if
               | he desires.
        
               | dandanua wrote:
               | It doesn't prevent from physical torturing that can be
               | used to steal your coins. I've already seen a bunch of
               | news about missing or killed people in this field. The
               | creator is also probably dead.
        
               | eecc wrote:
               | It still acts as a token for debt, and the underlying
               | force of that is violent retribution for default
        
               | lucb1e wrote:
               | I think you missed the last paragraph.
        
         | louwhopley wrote:
         | Similar to many Mastercard/Visa cards. The electronic chip on
         | the card is capable of actually storing the balance and then
         | syncing it back when it reaches a terminal machine that's
         | connected to the internet.
         | 
         | In my experience, many (most) chip-card based transport systems
         | for busses or trains (eg tap n go) operates in this offline
         | mode where it only syncs when you go to the kiosk to top it up.
         | 
         | It uses cryptographic methods to securely store and update the
         | balance. The chip itself is an embedded processor.
        
           | sargun wrote:
           | How do you solve the FLP problem?
           | 
           | e.g.
           | 
           | Kiosk->Device: Give me $100
           | 
           | Device: Subtract $100 from myself
           | 
           | Device->Kiosk: Send $100 (fail)
           | 
           | Alternatively, what if this happens the other direction?
        
             | texse wrote:
             | Technically FLP impossibility only applies to deterministic
             | algorithms, not randomized ones, otherwise no consensus
             | protocol would work. So you could imagine a complicated
             | technical solution that could work (eg. treating everything
             | as a big Raft cluster and using Raft's membership changes
             | every time a device is connected / disconnected).
             | 
             | In practice the solution is to realize that failures are
             | rare (especially compared to events like the soldier simply
             | misplacing the card), and to have a trusted human available
             | to resolve any issues that do occur.
        
             | wyattpeak wrote:
             | Atomic transactions, as with any database. After sending
             | the money, confirm that it arrived. If it didn't, undo the
             | subtraction.
             | 
             | That said, shoddy implementations of these systems often do
             | fail in numerous ways. As an end-user, you really just have
             | to live with it.
        
               | sargun wrote:
               | What protocol guarantees that there is an atomic
               | transaction, in the presence of faults, in such a system?
        
             | lmz wrote:
             | Those cards typically store the last few transactions (e.g.
             | [0] is an Android app that can display transit card usage
             | history), so it should be possible to code idempotency into
             | the card firmware.
             | 
             | [0]: https://play.google.com/store/apps/details?id=com.code
             | butler...
        
       | sneak wrote:
       | > _This method allows soldiers to purchase goods and services at
       | U.S. military posts and canteens, without carrying cash, or
       | manage their personal bank accounts while on deployment or in
       | training. The program reduces the amount of American currency
       | required overseas, reduces theft, saves thousands of man-hours in
       | labor, helps reduce the risk of transporting cash in combat
       | environments, and increases security and convenience for service
       | members._
       | 
       | It also prevents soldiers from being able to trade easily with
       | anyone who isn't an authorized card terminal user.
        
         | systemvoltage wrote:
         | It doesn't prevent them from carrying physical cash. They can
         | still do that.
        
         | someperson wrote:
         | Famously instant ramen noodles is the currency of choice for
         | people in prison: small, uniform and non-perishable.
         | 
         | Just like every other society, in the absence of cash I'm sure
         | soldiers have developed a bartering economy. Likely including
         | to acquire drug/alcohol/tobacco products that may be otherwise
         | banned. You sell me your old Nintendo Switch and I'll use my
         | EagleCash card to buy you 100 packs of instant ramen at company
         | store [1] prices.
         | 
         | Also, if anybody has a somewhat-trusted human network, it's
         | possible to do Hawala [2] transfers across different financial
         | systems without any actual foreign exchange transactions across
         | the boundaries.
         | 
         | [1] https://en.wikipedia.org/wiki/Company_store
         | 
         | [2] https://en.wikipedia.org/wiki/Hawala
        
           | eru wrote:
           | Couldn't soldiers also just use cash to augment their
           | trading? Or is that specifically banned?
        
             | sneak wrote:
             | Hard to get much of your US bank account contents as USD
             | cash when you're off on a military base enclave in some
             | foreign land. It's less hard (but still expensive and
             | inconvenient) to get it in the local currency.
             | 
             | You're also capped at relatively small amounts (a few
             | hundred bucks of local currency per day).
        
         | chipsa wrote:
         | It's possible to still use cash on deployed bases. But this
         | reduces the need to use cash for things like: buying from
         | random morale things, like the Fox at the 'Deid.
        
           | someperson wrote:
           | > buying from random morale things, like the Fox at the 'Deid
           | 
           | Took a bit of searching to understand what you meant: buying
           | drinks at the Fox Sports Bar located in Al Udeid Air Base
           | within the nation of Qatar.
        
       | ForHackernews wrote:
       | This sounds like a better alternative to bitcoin! I guess it
       | requires a trusted central authority, but for most users that's a
       | feature not a bug, and it sounds like it has a load of
       | advantages:
       | 
       | - Faster transactions
       | 
       | - Can work "offline" (to some extent)
       | 
       | - No wasted energy calculating redundant sha256
       | 
       | - Able to rectify fraudulent transactions
        
         | alisonkisk wrote:
         | What use case is there for this where it's better than bitcoin?
         | 
         | This is just a local payment system, that's existed for
         | centuries as scrip. ("On a computer" doesn't change the nature
         | of it.)
         | 
         | Centralization undermines the purpose of bitcoin.
        
           | ForHackernews wrote:
           | > What use case is there for this where it's better than
           | bitcoin?
           | 
           | Any situation where you want to purchase legal goods or
           | services? Or hold some money temporarily in a low-volatility
           | cash-like form?
        
           | geraldcombs wrote:
           | It's backed by a nation-state that has carrier groups?
        
         | H8crilA wrote:
         | Lol you just described credit cards.
        
           | ForHackernews wrote:
           | No, because credit cards charge exorbitant interest rates.
           | This is more analogous to electronic cash, since the value is
           | stored on the card.
        
           | lxgr wrote:
           | Stored value cards are different from debit cards: Their
           | value is physically stored on the chip, rather than the card
           | just being a reference to some centrally maintained account.
           | 
           | As a consequence, they are usable completely offline and with
           | very low latency.
        
           | Multicomp wrote:
           | this was tried in the UK in the late 90s (see !w Mondex) ...
           | i sooo wish it was a thing today!
        
       | [deleted]
        
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