https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=199.27.128.29&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T17:22:59ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:288:_Elevator&diff=96608Talk:288: Elevator2015-06-28T10:45:21Z<p>199.27.128.29: </p>
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<div>That certainly is a distinctive landscape. Does anybody know of any literary (or otherwise) allusion? [[Special:Contributions/108.162.219.223|108.162.219.223]] 02:24, 8 January 2014 (UTC)<br />
:I can't help but think of the Wood Between the Worlds from The Chronicles of Narnia. It's probably not it, though. Those look more like lakes than pools of water. Also, there's that larger body of water. {{unsigned ip|108.162.222.47}}<br />
:Looks a bit like the Boundary Waters of northern Minnesota. Not sure why it would be that, however. [[Special:Contributions/173.245.54.194|173.245.54.194]] 14:44, 7 November 2014 (UTC)<br />
:The location might be the Lena Delta in northern Russia. This is also referenced in xkcd [https://xkcd.com/1169/ 1169] "Expedition" by clicking on the comic. [[Special:Contributions/108.162.237.188|108.162.237.188]] 04:59, 6 March 2015 (UTC)<br />
<br />
Why are the floors labeled backwards from the reality, with the lowest floor at the top? Is this common in the U.S.?[[Special:Contributions/141.101.81.220|141.101.81.220]] 13:21, 19 May 2014 (UTC)<br />
:No, most, if not all, buildings in the US have the highest floor on top and the lowest floor on bottom, with everything else in descending order as you look from top to bottom. [[User:Mulan15262|Mulan15262]] ([[User talk:Mulan15262|talk]]) 03:33, 10 June 2014 (UTC)Mulan15262<br />
:Floors appear with the highest on top and the lowest on the bottom. However, the number one is assigned to the ground floor or the floor above it. Normally, basements are not assigned a number, and are simply marked with the letter "B". However, in buildings with more than one floor below ground, they may be numbered. In other words, the numbering might not be backwards, if 1 is 1 floor below ground, 2 is 2 floors below ground, etc. In the television show Stargate SG-1, there are elevators that stop at "sub-levels" (floors below ground) inside Cheyenne Mountain. In real life, elevators that go multiple floors below ground are found in underground parking garages, subway stations, etc.<br />
[[Special:Contributions/173.245.48.97|173.245.48.97]] 02:49, 8 December 2014 (UTC)<br />
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With the landscape, i cant help but think of the dead marshes from LOTR [[Special:Contributions/108.162.250.218|108.162.250.218]] 02:33, 21 November 2014 (UTC)<br />
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I've just noticed that the image, with the heavy blues and greens, seems to move when you read the explanation below. It seems to be some sort of motion illusion, though I don't know the exact name of it. [[User:Kirdneh|Kirdneh]] ([[User talk:Kirdneh|talk]]) 02:25, 15 December 2014 (UTC)<br />
<br />
Adding your own labels is also seen in What-if xkcd 35. --[[Special:Contributions/199.27.128.29|199.27.128.29]] 10:45, 28 June 2015 (UTC)</div>199.27.128.29https://www.explainxkcd.com/wiki/index.php?title=1093:_Forget&diff=728191093: Forget2014-08-03T05:15:43Z<p>199.27.128.29: /* Explanation */ Grammar "fix" on the 9/11 explanation; removed the first "that" to create a complete sentence</p>
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<div>{{comic<br />
| number = 1093<br />
| date = August 10, 2012<br />
| title = Forget<br />
| image = forget.png<br />
| titletext = 'Baby Got Back' turned 20 this year. My favorite nostalgia show is VH1's 'I Love The Inexorable March of Time Toward the Grave That Awaits Us All.'<br />
}}<br />
<br />
==Explanation==<br />
The median age in {{w|USA}} is currently about 37 years. Assuming that you must be at least five years old to remember a cultural event later, this means that anything that happened longer ago than the fifth birthday of someone who is 37 years now is remembered by a minority of people today. This applies to any event prior to 1980, so here in 2012, the majority of Americans are too young to remember the Seventies. However, according to census estimation the median will raise in the future, so instead of a 32 years gap between event and the moment when most people can't remember it, the gap becomes 35 years (implying a median of some 40 years).<br />
<br />
'''2013: The Carter presidency''' {{w|Jimmy Carter}} was the {{w|President of the United States}} from 1977-1981. He lost all popularity after he was viewed as mishandling several crises during his presidency, including the {{w|Three Mile Island accident}}, the {{w|Iran Hostage crisis}}, and the "{{w|stagflation}}" of the late 1970s. According to Wikipedia, his decisions to reinstate registration for the draft and his decision to boycott the {{w|1980 Summer Olympics}} in Moscow (over the 1979 Soviet invasion of Afghanistan) helped contribute to his defeat in the 1980 Presidential campaign.<br />
<br />
'''2014: The Reagan shooting''' References the 1981 {{w|Reagan assassination attempt|assassination attempt}} on the then American president, {{w|Ronald Reagan}}.<br />
<br />
'''2015: The Falkland Islands War''' This is in reference to the {{w|Falklands War|brief outbreak of hostilities}} between the {{w|UK}} and {{w|Argentina}} over the {{w|Falkland Islands|Falkland Islands (Islas Malvinas)}} located off the shore of Argentina claimed by both but controlled by the UK. Even to this date, tensions remain high over the ownership of these islands, and while many people alive today weren't alive to witness it, it nevertheless remains present in the collective psyche of both nations.<br />
<br />
'''2017: The first Apple Macintosh''' The {{w|Macintosh}} was a line of computers created by {{w|Apple Inc.|Apple}}, first introduced in 1984, with the {{w|Macintosh 128K}}.<br />
<br />
'''2018: New Coke''' References a public relations blunder that the Coca Cola corporation undertook in attempting to reformulate its cola recipe, the new formula called {{w|New Coke}} popularly. The public backlash so shook the company that they reintroduced the original recipe as {{w|Coca-Cola Classic}} within 3 months. New Coke was eventually rebranded from Coca-Cola to Coke II, and then discontinued. Coca-Cola Classic has quietly been rebranded back to simply Coca-Cola, as it originally was. The "New Coke" introduction is considered one of the biggest PR blunders from a major company ever.<br />
<br />
'''2019: Challenger''' The {{w|Space Shuttle Challenger|Challenger}} was a {{w|NASA}} space shuttle, which was launched in 1986, but {{w|Space Shuttle Challenger disaster|exploded}} 72 seconds into its flight, killing everyone aboard, including {{w|Christa McAuliffe}}, a teacher selected to be the first teacher in space.<br />
<br />
'''2020: Chernobyl''' Refers to the 1986 meltdown of a {{w|Chernobyl|nuclear power plant}} in the {{w|Ukranian SSR}} (then a part of the Soviet Union). The meltdown forced the nearby city of {{w|Pripyat}} to be abandoned, and it remains a ghost town today.<br />
<br />
'''2021: Black Monday''' Refers to the 1987 {{w|Black Monday (1987)|day}} of the largest one-day {{w|stock market}} drop in history.<br />
<br />
'''2022: The Reagan presidency''' {{w|Ronald Reagan}} was an American president from 1981 to 1989, and was a generally well received president known for ending the Cold War, oversaw the {{w|Iran–Contra affair}}, {{w|Invasion of Grenada|invading Grenada}}, and issuing forth a number of new {{w|Reaganomics|economic policies}}.<br />
<br />
'''2023: The Berlin Wall''' Refers to the {{w|Berlin Wall|barrier}} surrounding the western-controlled part of {{w|Berlin}}. It was erected by the {{w|East Germany|East German}} Government in 1961 to stop illegal emigration to West Berlin-the western-controlled enclave after the ending of the second WW. After a friendly revolution in 1989, emigration to West Berlin (and West German in general) was granted suddenly and very surprisingly again on November 9, 1989. The following rush of people to the Wall from East (to cross the border) and from West (to welcome friends and relatives) in that night coined the figurative "Fall of the Wall", preceding the actual reunion of Germany in 1990 and (almost) complete demolition of the Wall.<br />
<br />
'''2024: HammerTime''' Refers to a refrain in {{w|MC Hammer|MC Hammer's}} 1990 hit song {{w|U Can't Touch This}}; [[Randall Munroe]] makes reference to this song elsewhere in his comics, too (specifically [[108: M.C. Hammer Slide]] and [[210: 90's Flowchart]]).<br />
<br />
'''2025: The Soviet Union''' Refers to the cold-war adversary of the United States, emerging after the end of {{w|World War I}} and only collapsing in 1991.<br />
<br />
'''2026: The LA Riots''' Refers to the {{w|1992 Los Angeles riots|massive riots}} occurring at the release of the verdict acquitting the officers accused of the {{w|Rodney King}} beatings in 1992.<br />
<br />
'''2027: Lorena Bobbit''' Refers to the {{w|John and Lorena Bobbitt|woman}} who {{w|emasculated}} her husband in 1993.<br />
<br />
'''2028: The Forrest Gump release''' ''{{w|Forrest Gump}}'' was a 1994 drama starring {{w|Tom Hanks}} as a mentally disabled man, telling his spectacular life story. The movie had a highly successful release, and remains one of the greatest films of all time.<br />
<br />
'''2029: The Rwanda Genocide''' Refers to the 1994 {{w|Rwandan genocide}}, where an estimated 800,000 people were killed.<br />
<br />
'''2030: OJ Simpson's Trial''' The {{w|O. J. Simpson murder case|O.J. Simpson trial}} was a famous criminal case during which {{w|O.J. Simpson}}, a professional football player, was {{w|acquitted}} of the murder of {{w|Nicole Simpson}} and {{w|Ronald Goldman}}. He was later arrested and jailed for other crimes, including armed robbery and kidnapping.<br />
<br />
'''2031: Clinton's reelection''' {{w|Bill Clinton}} was the American president from 1993 to 2001. He won his second term in the {{w|United States presidential election, 1996|1996 presidential election}}. During his second term, he faced controversy during an {{w|impeachment}} trial, for which he was acquitted, and a large number of pardons he made on his last day of office. Clinton was a generally favoured president, exiting his presidency with a high approval rate.<br />
<br />
'''2032: Princess Diana''' {{w|Princess Diana}} was a famous {{w|Commonwealth}} princess who made headlines after her 1997 {{w|Death of Diana, Princess of Wales|death}} in a car crash.<br />
<br />
'''2033: Clinton's impeachment''' In 1998, the American {{w|Congress}} voted to {{w|Impeachment of Bill Clinton|impeach}} then-president Clinton, based on allegations that he {{w|Lewinsky scandal|lied}} about relations with a {{w|Monica Lewinsky|White House intern}}. He was later acquitted.<br />
<br />
'''2034: Columbine''' Refers to the 1999 {{w|Columbine High School massacre}}, where 13 people were killed by a {{w|Eric Harris and Dylan Klebold|pair of shooters}}.<br />
<br />
'''2035: Forgot About Dre''' Refers to the {{w|Grammy}} winning 2000 song, {{w|Forgot About Dre}}, by the rapper {{w|Dr. Dre}}.<br />
<br />
'''2036: 9/11''' Refers to the {{w|9/11}} event, in 2001, where terrorists crashed two planes into the {{w|World Trade Center}} towers, in {{w|New York}}. Two other planes crashed that day: one into the {{w|The Pentagon}}, and one in a field outside of {{w|Shanksville, Pennsylvania}} (presumably on its way to crashing into the Capitol Building).<br />
<br />
'''2037: VH1's I love the 80s''' ''{{w|I Love the '80s (U.S. TV series)|I Love the '80s}}'' was a 2002 nostalgia TV series by {{w|VH1}}.<br />
<br />
'''2038: A time before Facebook''' Refers to the online social media site, {{w|Facebook}}, launched in 2004.<br />
<br />
'''2039: VH1's I love the 90s''' ''{{w|I Love the '90s (U.S. TV series)|I Love the '90s}}'' was a TV series airing in 2004.<br />
<br />
'''2040: Hurricane Katrina''' {{w|Hurricane Katrina}} was a devastating 2005 hurricane that hit {{w|New Orleans}}, killing almost 2000 people and causing 81 billion dollars in damage.<br />
<br />
'''2041: The planet Pluto''' {{w|Pluto}} is a {{w|dwarf planet}} in our solar system. Up until 2006, Pluto was considered to be a planet.<br />
<br />
'''2042: The first iPhone''' {{w|Apple}}'s first iPhone was released in 2007.<br />
<br />
'''2043: The Bush presidency''' {{w|George W. Bush}} was the American presidency from 2001 to 2009. He was criticized for the wars on {{w|War in Afghanistan (2001%E2%80%93present)|Afghanistan}} and {{w|Iraq War|Iraq}}, poor handling of Hurricane Katrina, and seeing the United States enter a recession. His approval peaked after the 9/11 attacks, but had fallen to historical lows by the end of his second term, making him one of the least liked US presidents.<br />
<br />
'''2044: Michael Jackson''' Refers to the {{w|Michael Jackson|pop singer}} who died of drug overdose in 2009.<br />
<br />
'''2045: Trying to say Eyjafjallajökull''' Is a reference to a volcano in {{w|Iceland}} that {{w|Eyjafjallajökull#2010 eruptions|erupted}} in 2010. The eruption threw volcanic ash several kilometres up in the atmosphere, which led to air travel disruption in northwest Europe for six days.<br />
<br />
'''2046: The Arab Spring''' Refers to the {{w|Arab Spring|wave of revolutions}} that began in late 2010, where many Arabic nations overthrew leaders and started civil wars, with many nations converting to democracies.<br />
<br />
'''2047: Anything embarrassing you do today''' Refers to the fact that in 35 years, the majority of Americans will not have been around on this date.<br />
<br />
The title text is in reference to the vastly over-saturated programming on VH1 dedicated to the history of the TV universe.<br />
<br />
==Transcript==<br />
:'''When Will We Forget?'''<br />
:Based on US Census Bureau ''National Population Projections''<br />
:Assuming we don't remember cultural events from before age 5 or 6<br />
<br />
:By this year: The majority of Americans will be too young to remember:<br />
:2012: The seventies<br />
:2013: The Carter presidency<br />
:2014: The Reagan shooting<br />
:2015: The Falkland Islands war<br />
:2016: ''The return of the Jedi''release<br />
:2017: The first Apple Macintosh<br />
:2018: New Coke<br />
:2019: ''Challenger''<br />
:2020: Chernobyl<br />
:2021: Black Monday<br />
:2022: The Reagan presidency<br />
:2023: The Berlin Wall<br />
:2024: HammerTime<br />
:2025: The Soviet Union<br />
:2026: The LA Riots<br />
:2027: Lorena Bobbit<br />
:2028: The ''Forrest Gump'' release<br />
:2029: The Rwanda Genocide<br />
:2030: OJ Simpson's Trial<br />
:2031: Clinton's reelection<br />
:2032: Princess Diana<br />
:2033: Clinton's impeachment<br />
:2034: Columbine<br />
:2035: ''Forgot About Dre''<br />
:2036: 9/11<br />
:2037: VH1's ''I love the 80s''<br />
:2038: A time before Facebook<br />
:2039: VH1's ''I love the 90s''<br />
:2040: Hurricane Katrina<br />
:2041: The planet Pluto<br />
:2042: The first iPhone<br />
:2043: The Bush presidency<br />
:2044: Michael Jackson<br />
:2045: Trying to say ´´Eyjafjallajökull``<br />
:2046: The Arab Spring<br />
:2047: Anything embarrassing you do today<br />
<br />
{{comic discussion}}<br />
[[Category:Charts]]</div>199.27.128.29https://www.explainxkcd.com/wiki/index.php?title=936:_Password_Strength&diff=65188936: Password Strength2014-04-11T11:49:40Z<p>199.27.128.29: /* Explanation */ Fixed a typo</p>
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<div>{{comic<br />
| number = 936<br />
| date = August 10, 2011<br />
| title = Password Strength<br />
| image = password strength.png<br />
| titletext = To anyone who understands information theory and security and is in an infuriating argument with someone who does not (possibly involving mixed case), I sincerely apologize.<br />
}}<br />
<br />
==Explanation==<br />
Computer security consultant Mark Burnett has posted a [http://xato.net/passwords/analyzing-the-xkcd-comic/ discussion and analysis] of this comic on his blog.<br />
<br />
This comic is saying that the password in the top frames "Tr0ub4dor&3" is easier for password cracking software to guess because it has less entropy than "correcthorsebatterystaple" and also more difficult for a human to remember, leading to insecure practices like writing the password down on a post-it attached to the monitor.<br />
<br />
In simple cases the {{w|Entropy (information theory)|entropy}} of a password is calculated as ''a^b'' where ''a'' is the number of allowed symbols and ''b'' is its length. A dictionary word (however long) has an entropy of around 65000, i.e. 16 bits. A truly random string of length 11 (not like "Tr0ub4dor&3", but more like "J4I/tyJ&Acy") has 94^11 = 72.1 bits. However the comic shows that "Tr0ub4dor&3" has only 28 bits of entropy. Another way of selecting a password is to have 2048 "symbols" (common words) and select only 4 of those symbols. 2048^4 = 44 bits, much better than 28.<br />
<br />
It is absolutely true that people make passwords hard to remember because they think they are "safer", and it is certainly true that length, all other things being equal, tends to make for very strong passwords and this can confirmed by using [http://rumkin.com/tools/password/passchk.php rumkin.com's password strength checker]. Even if the individual characters are all limited to [a-z], the exponent implied in "we added another lowercase character, so multiply by 26 again" tends to dominate the results.<br />
<br />
In addition to being easier to remember, long strings of lowercase characters are also easier to type on smartphones and {{w|Virtual keyboard|soft keyboards}}.<br />
<br />
xkcd's password generation scheme requires the user to have a list of 2048 common words (log<sub>2</sub>(2048) = 11). For any attack we must assume that the attacker knows our password generation algorithm, but not the exact password. In this case the attacker knows the 2048 words, and knows that we selected 4 words, but not which words. The number of combinations of 4 words from this list of words is 2<sup>11</sup>&times;4 = 44 bits. For comparison, the [http://world.std.com/~reinhold/dicewarefaq.html#calculatingentropy entropy offered by Diceware's 7776 word list is 13 bits per word]. If the attacker doesn't know the algorithm used, and only knows that lowercase letters are selected, the "common words" password would take even longer to crack than depicted. 25 ''random'' lowercase characters would have [http://www.wolframalpha.com/input/?i=log2%2826^25%29 117 bits of entropy], vs 44 bits for the common words list.<br />
<br />
{{w|Steve Gibson (computer programmer)|Steve Gibson}} from the {{w|Security Now}} podcast did a lot of work in this arena and found that the password <code>D0g.....................</code> (24 characters long) is stronger than <code>PrXyc.N(n4k77#L!eVdAfp9</code> (23 characters long) because both have at least one uppercase letter, lowercase letter, number, and "special" character, so length trumps perceived complexity. Steve Gibson makes this very clear in his password haystack [https://www.grc.com/haystack.htm reference guide and tester]:<br />
:"Once an exhaustive password search begins, '''the most important factor''' is password length!"<br />
<br />
The important thing to take away from this comic is that longer passwords are better because each additional character adds much more time to the breaking of the password. That's what [[Randall]] is trying to get through here. Complexity does not matter unless you have length in passwords. Complexity is more difficult for humans to remember, but length is not.<br />
<br />
;Example<br />
Below there is a detailed example which shows how different rules of complexity work to generate a password with supposed 44 bits of entropy. The examples of expected passwords were generated in random.org.(*)<br />
<br />
If ''n'' is the number of symbols and ''L'' is the length of the password, then ''L'' = 44 / log<sub><small>2</small></sub>(n).<br />
<br />
{|class="wikitable"<br />
!Symbols<br />
!Number of symbols<br />
!Minimum length<br />
!colspan="2"|Examples of expected passwords<br />
!Example of an actual password<br />
!Actual bits of entropy<br />
!Comment<br />
|-<br />
|a||26||9.3||mdniclapwz||jxtvesveiv||troubadorx||16+4.7 = 20.7||Extra letter to meet length requirement; log<sub><small>2</small></sub>(26) = 4.7<br />
|-<br />
|rowspan="2"|a 9<br />
|rowspan="2"|36<br />
|rowspan="2"|8.5<br />
|rowspan="2"|qih7cbrmd<br />
|rowspan="2"|ewpltiayq<br />
|tr0ub4d0r||16+3=19||3 = common substitutions in the comic<br />
|-<br />
|troubador1||16+3.3=19.3||log<sub><small>2</small></sub>(10) = 3.3<br />
|-<br />
|a A||52||7.7||jAwwBYne||NeTvgcrq||Troubador||16+1=17||1 = caps? in the comic<br />
|-<br />
|a &amp;||58||7.5||j.h?nv),||c/~/fg\:||troubador&amp;||16+4=20||4 = punctuation in the comic<br />
|-<br />
|a A 9||62||7.3||cDe8CgAf||RONygLMi||Tr0ub4d0r||16+1+3=20||1 = caps?; 3 = common substitutions<br />
|-<br />
|a 9 &amp;||68||7.2||_@~"#^.2||un$l&#x7c;!f]||tr0ub4d0r&amp;||16+3+4=23||3 = common substitutions; 4 = punctuation<br />
|-<br />
|a A 9 &amp;||94||6.7||Re-:aRo||^$rV{3?||Tr0ub4d0r&||16+1+3+4=24||1 = caps?; 3 = common substitutions; 4 = punctuation<br />
|-<br />
|rowspan="2"|common words<br />
|rowspan="2"|2048<br />
|rowspan="2"|4<br />
|rowspan="2"|reasonable&#8203;retail&#8203;sometimes&#8203;possibly<br />
|rowspan="2"|constant&#8203;yield&#8203;specify&#8203;priority||reasonable&#8203;retail&#8203;sometimes&#8203;possibly||11&times;4=44||Go to random.org and select 4 random integers between 1 and 2048; then go to your list of common words <br />
|-<br />
|correct&#8203;horse&#8203;battery&#8203;staple<br />
|0<br />
|Because of this comic this password has no entropy<br />
|}<br />
<br />
:a = lowercase letters<br />
:A = uppercase letters<br />
:9 = digits<br />
:&amp; = the 32 special characters in an American keyboard; Randall assumes only the 16 most common characters are used in practice (4 bits)<br />
<br />
:(*)&nbsp;The use of random.org explains why <code>jAwwBYne</code> has two consecutive w's, why <code>Re-:aRo</code> has two R's, why <code>_@~"#^.2</code> has no letters, why <code>ewpltiayq</code> has no numbers, why "constant yield" is part of a password, etc. A human would have attempted at passwords that looked random.<br />
<br />
==Transcript==<br />
:The comic illustrates the relative strength of passwords assuming basic knowledge of the system used to generate them.<br />
:A set of boxes is used to indicate how many bits of entropy a section of the password provides.<br />
:The comic is laid out with 6 panels arranged in a 3x2 grid.<br />
:On each row, the first panel explains the breakdown of a password, the second panel shows how long it would take for a computer to guess, and the third panel provides an example scene showing someone trying to remember the password.<br />
<br />
:[The password "Tr0ub4dor&3" is shown in the center of the panel. A line from each annotation indicates the word section the comment applies to.]<br />
<br />
:Uncommon (non-gibberish) base word<br />
:[Highlighting the base word - 16 bits of entropy.]<br />
:Caps?<br />
:[Highlighting the first letter - 1 bit of entropy.]<br />
:Common Substitutions<br />
:[Highlighting the letters 'a' (substituted by '4') and both 'o's (the first of which is substituted by '0') - 3 bits of entropy.]<br />
:Punctuation<br />
:[Highlighting the symbol appended to the word - 4 bits of entropy.]<br />
:Numeral<br />
:[Highlighting the number appended to the word - 3 bits of entropy.]<br />
:Order unknown<br />
:[Highlighting the appended characters - 1 bit of entropy.]<br />
:(You can add a few more bits to account for the fact that this is only one of a few common formats.)<br />
<br />
:~28 bits of entropy <br />
:2<sup>28</sup> = 3 days at 1000 guesses sec<br />
:(Plausible attack on a weak remote web service. Yes, cracking a stolen hash is faster, but it's not what the average user should worry about.)<br />
:Difficulty to guess: Easy.<br />
<br />
:[Cueball stands scratching his head trying to remember the password.]<br />
:Cueball: Was it trombone? No, Troubador. And one of the O's was a zero?<br />
:Cueball: And there was some symbol...<br />
:Difficulty to remember: Hard.<br />
<br />
:[The passphrase "correct horse battery staple" is shown in the center of the panel.]<br />
:Four random common words {Each word has 11 bits of entropy.}<br />
<br />
:~44 bits of entropy<br />
:2<sup>44</sup> = 550 years at 1000 guesses sec<br />
:Difficulty to guess: Hard.<br />
<br />
:[Cueball is thinking, in his thought bubble a horse is standing to one side talking to an off-screen observer. An arrow points to a staple attached to the side of a battery.]<br />
:Horse: That's a battery staple.<br />
:Observer: Correct!<br />
:Difficulty to remember: You've already memorized it<br />
<br />
:Through 20 years of effort, we've successfully trained everyone to use passwords that are hard for humans to remember, but easy for computers to guess.<br />
<br />
==External links==<br />
*Some info was used from the highest voted answer given to the question of "how accurate is this XKCD comic" at StackExchange [http://security.stackexchange.com/questions/6095/xkcd-936-short-complex-password-or-long-dictionary-passphrase].<br />
*Similarly, a question of "how right this comic is" was made at AskMetaFilter [http://ask.metafilter.com/193052/Oh-Randall-you-do-confound-me-so] and [[Randall]] responded [http://ask.metafilter.com/193052/Oh-Randall-you-do-confound-me-so#2779020 there].<br />
*Also the Wikipedia article on '{{w|Passphrase}}' is useful.<br />
*In case you missed it in the explanation, GRC's Steve Gibson has a fantastic page [https://www.grc.com/haystack.htm] about this (and may have prompted this comic, as his podcast [http://www.grc.com/sn/sn-303.htm] about this was posted the month before this comic).<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Math]]<br />
[[Category:Computers]]</div>199.27.128.29https://www.explainxkcd.com/wiki/index.php?title=Talk:1340:_Unique_Date&diff=62385Talk:1340: Unique Date2014-03-10T18:48:38Z<p>199.27.128.29: </p>
<hr />
<div>My first thought was that he makes fun of people that consider dates like the 12.12.12 as important. As any other date they occur only once and are thus not more special. [[Special:Contributions/108.162.254.66|108.162.254.66]] 04:37, 10 March 2014 (UTC)<br />
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:Good point, I have added something about that. [[Special:Contributions/108.162.246.117|108.162.246.117]] 04:49, 10 March 2014 (UTC)<br />
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Possibly related to the upcoming Pi Day. Also, next year's Pi Day will be 03-14-(20)15, which a few images going around on the Internet have made an annoyingly big deal about. [[Special:Contributions/108.162.237.64|108.162.237.64]] 06:24, 10 March 2014 (UTC)<br />
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So - Maybe I suck at searching (I do), but I can't find any information about us being limited to 4 digits in our calendar system...?[[Special:Contributions/173.245.53.107|173.245.53.107]] 08:38, 10 March 2014 (UTC)<br />
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:Most of the computer software that handles dates would have problems with more (or less) then four digits. Why bother with variable year length when you can just take the first four characters of "2014-03-10" and it works for the next 8 thousand years? [[Special:Contributions/103.22.200.103|103.22.200.103]] 09:42, 10 March 2014 (UTC)<br />
:Also, most digital displays are limited to four digits for the year. [[Special:Contributions/103.22.200.103|103.22.200.103]] 09:43, 10 March 2014 (UTC)<br />
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::And I don't think we actually start address that sooner that in September 9999. It will be Y2K over again! .... not sure where will people of 9999 get {{w|Fortran}} and {{w|Cobol}} programmers, though. Maybe we should freeze some before we run out of them. :-) -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:20, 10 March 2014 (UTC)<br />
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:I'm with you. I suppose there may be places where leading zeros are used (somewhere in software where memory space has been set aside, I suppose) but I can't think of '''any''' common system where one has to use five digits when using a four digit number.<br />
:When we get to December 31, 9999 (assuming he Gregorian calendar is still in use (BIG assumption)) the next day will simply be January 1, 10000 because, as you said, the Gregorian calendar isn't limited to four-digit years. And, as I say, anyone who think there is some problem with writing years as four digit numbers is simply demonstrating that they are not someone to take seriously. [[Special:Contributions/199.27.128.84|199.27.128.84]] 16:32, 10 March 2014 (UTC)<br />
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After visiting the website for the "Long Now Foundation", I find I'm left wondering - why, oh why, would they stop at using a five digit year? why not six? eight? ten? sixteen? thirty-two? [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 12:06, 10 March 2014 (UTC)<br />
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I think the point in the comic title is that writing years always with 5 digits is as significant as the zero to the left it will take to do so for most of the next 8000 years. [[User:FlavianusEP|FlavianusEP]] ([[User talk:FlavianusEP|talk]]) 12:25, 10 March 2014 (UTC)<br />
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My first thought was that the comic was about date formats and yyyy-mm-dd being better than yy-mm-dd or dd.mm.yy. [[Special:Contributions/173.245.53.138|173.245.53.138]] 12:40, 10 March 2014 (UTC)<br />
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;Dynamic?<br />
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Wanna bet that this comic always shows the current date?--[[User:Henke37|Henke37]] ([[User talk:Henke37|talk]]) 10:23, 10 March 2014 (UTC)<br />
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:Haha, that's a great observation! I wish it were so, I'll check again tomorrow. If it's not, someone email Mr. Munroe to make it so, great idea. {{unsigned|Adityarajbhatt}}<br />
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:It's 00:07 (11th of March) right now in China where I am currently located and it still shows 10th of March...just for the record [[Special:Contributions/108.162.225.191|108.162.225.191]] 16:13, 10 March 2014 (UTC)<br />
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It's funny that Randall seems to have never heard of [http://tools.ietf.org/html/rfc2550 RFC 2550], which goes than the Long Now Foundation in expanding the representable date range. [[Special:Contributions/173.245.53.161|173.245.53.161]] 15:05, 10 March 2014 (UTC)<br />
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:Technically, there will be another 2014-03-10; on October 3rd. - [[Special:Contributions/108.162.219.65|108.162.219.65]] 16:01, 10 March 2014 (UTC)<br />
::It would actually be 2014-10-03 "under our system" as stated in the comic. Technically. [[Special:Contributions/108.162.237.64|108.162.237.64]] 17:14, 10 March 2014 (UTC)<br />
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I wonder if this is also somehow related to the [http://en.wikipedia.org/wiki/Interesting_number_paradox Interesting number paradox]. [[Special:Contributions/199.27.128.29|199.27.128.29]] 18:48, 10 March 2014 (UTC)</div>199.27.128.29https://www.explainxkcd.com/wiki/index.php?title=Talk:526:_Converting_to_Metric&diff=60883Talk:526: Converting to Metric2014-02-24T03:06:00Z<p>199.27.128.29: </p>
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<div>Why is 3L a two-liter bottle?[[Special:Contributions/75.69.96.225|75.69.96.225]] 21:16, 28 April 2013 (UTC)<br />
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:Because this is America and we supersize our sodas! {{unsigned ip|72.68.9.56}}<br />
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:It is the volume of the bottle itself. I have added this explanation. [[User:Sten|Sten]] ([[User talk:Sten|talk]]) 22:39, 29 August 2013 (UTC)<br />
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:A 2L bottle doesn't take 3L of space, not even close. I also think it's a reference to overly large drinks in the US. But even if it isn't, the current explanation is wrong. [[Special:Contributions/108.162.229.34|108.162.229.34]] 22:28, 12 December 2013 (UTC)<br />
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: I suspect he's just messing with us, because the approximate volume of a two-liter bottle should be obvious. Many beverages sold in the US are already labeled in metric. Soda is routinely sold in one and two liter bottles, with three-liter bottles common in some markets. Bottled water is often sold in liters and half-liters. Liquor and wine are sold in 375 and 750 mL bottles. Also, since 1 quart = 946 mL, an approximate (+/- 5%) mental conversion from quarts to liters is already quite easy. [[User:Fryhole|Fryhole]] ([[User talk:Fryhole|talk]]) 01:35, 25 January 2014 (UTC)<br />
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My names River, that is all --[[Special:Contributions/139.216.242.254|139.216.242.254]] 02:52, 29 August 2013 (UTC)<br />
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:Tick tock, goes the clock, 'till River kills the Doctor<br />
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Earth's hottest is 70,7 °C... [[Special:Contributions/199.27.128.29|199.27.128.29]] 03:06, 24 February 2014 (UTC)</div>199.27.128.29